November/December 2009 Volume 16, No. 6 (TS-PU-0011-09)
Wheel and Tire
Diagnosis
Two characteristics of a wheel/tire assembly
have a profound effect on vehicle ride quality
— balance and radial force variation.
Balance is related to the mass of the
wheel/tire assembly, and radial
force is related to the effective
"roundness" of the assembly.
Both can contribute to vibration
being transmitted into the vehicle.
Balance is addressed by installing
weights to the perimeter of the
wheel to counter the imbalance.
Radial force variation is addressed
by match mounting or by replacing a wheel or tire.
The first step in diagnosis is to
visually inspect the wheel and
tire. Look for:
• Missing balance weights
• Bent rim flange
• Irregular tire wear
• Incomplete bead seating
• Tire irregularities
(including pressure settings)
• Mud/ice build-up in the wheel
• Aftermarket components
If a road test indicates a shake or vibration, check the imbalance of each
wheel/tire assembly on a calibrated off-car dynamic balancer.
Balance
If you can see or feel the vibration in the steering wheel, it is very likely to be a
wheel/tire first order (one pulse per revolution) disturbance caused by imbalance
or non-uniformities in tires, wheels or hubs. Balance measures how the wheel/tire
assembly's mass is distributed around its rotating axis. This measurement is
accomplished by spinning the assembly at high speed. Balance is checked and
corrected first. Often, vibration issues are corrected by simply balancing the
assembly. If vibration or shake still exists, radial force variation may be the cause.
Balancer calibration and maintenance, proper attachment of the wheel to the
balancer, and proper balance weights are all required for a quality balance.
However, a perfectly balanced wheel/tire assembly can still be “oval-shaped”
and cause a vibration.
Radial Force Variation
Radial force measures how "round" the assembly is when rolling under a load.
Variations in tire sidewall stiffness, for instance, have an effect on radial force.
continued on page 3
1
IN THIS ISSUE
Wheel and Tire Diagnosis . . . . . . . . . . . . . .1
ACDelco Launches Redesigned
OE Oil Filter . . . . . . . . . . . . . . . . . . . . . . . . . . .2
New ACDelco RTV Engine Sealant . . . . . .2
Tire Sealants . . . . . . . . . . . . . . . . . . . . . . . . .3
Winter Car Care . . . . . . . . . . . . . . . . . . . . . . .4
Short-term SPS Subscription . . . . . . . . . . .5
Vibe PCM Calibrations Available
via TIS2Web . . . . . . . . . . . . . . . . . . . . . . . . . .5
2010 MACS Convention Preview . . . . . . . .5
TSS Q&A . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Global Refrigerant
Development Continues . . . . . . . . . . . . . . . .6
Tech Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Training Update . . . . . . . . . . . . . . . . . . . . . . .8
ON THE WEB
– www.acdelcotechconnect.com, click
the TechConnect Magazine link, or
– Log in to the ACDelco LMS, click the
Resources link
ACDelco Launches
Redesigned OE Oil Filter
ACDelco has announced a redesigned Original Equipment (OE) oil filter that offers
ACDelco’s exclusive Duraguard® media in a smaller package.
The new OE filter applications PF46E, PF47E, PF52E and PF61E will be installed
in applicable new GM models. The new oil filter features:
• Duraguard
media, ACDelco’s
trademarked
synthetic
cellulose-blended
media that
efficiently filters
particles as small
as 10 microns —
1/3 the width
of a human hair
— to ensure a
clean supply of
oil to engine
components
ACDelco TechConnect is published bi-monthly
and online for technicians of Total Service
Support (TSS) and Key Fleet accounts to
provide timely service information, increase
knowledge and improve the performance of
the service center.
Publisher:
Mike DeSander
ACDelco
E-mail /
mike.desander@gm.com
Editor:
Mike Militello
ACDelco
E-mail /
michael.militello@gm.com
New OE oil filter
• A full cover baseplate that allows easy installation in blind applications
• Increased efficiency and higher burst and collapse strength
• A new Nylon core that provides better flow characteristics and improved
collapse strength
• A combination relief and anti-drainback valve that prevents dry starts and
assures oil flow (where applicable)
Technical Editor:
Mark Spencer
E-mail /
mspencer@gpworldwide.com
Production Manager:
Marie Meredith
Desktop Publishing:
Design
ACDelco part number with corresponding GM part number
Classic Design
PF46
19256041
PF47
19256042
PF52
19256043
PF61
19256044
New OE Design
PF46E
19210283
PF47E
19210284
PF52E
19210285
PF61E
19210286
In addition to the new OE design oil filter applications, the original filters
(PF46, PF47, PF52 and PF61) continue to be available in a classic design.
For more information about the new ACDelco oil filters, refer to ACDelco
bulletin #09D-142.
– Thanks to Bob Malone
New ACDelco RTV
Engine Sealant
ACDelco has announced the addition of a one-component, room-temperature
vulcanizing (RTV) engine sealant, part number 10-2006, that is recommended for all
engine applications. This is the original production sealant used in GM engine plants.
This high viscosity product cures when exposed to air. The cured material has
superior adhesion and elongation properties and is very resistant to engine oils and
coolants, making it compatible with all synthetic, synthetic blend, and mineral oils
as well as engine coolant (including DEX-COOL® coolant). It is also safe for oxygen
sensors and will not corrode metal surfaces.
The assembly may be filled with oil or coolant immediately after applying the
sealant and torquing the bolts.
5by5 Design LLC
E-mail /
dkelly@5by5dzign.com
Write to: *
ACDelco TechConnect
P.O. Box 500
Troy, MI 48007-0500
:
On the Web:
To read and search recent issues of
TechConnect online:
– www.acdelcotechconnect.com,
click the TechConnect Magazine
link, or
– Log in to the ACDelco LMS, click
the Resources link
ACDelco service tips are intended for use by
professional technicians, not a “do-it-yourselfer.”
They are written to inform those technicians of
conditions that may occur on some vehicles, or to
provide information that could assist in the proper
service of a vehicle. Properly trained technicians
have the equipment, tools, safety instructions and
know-how to do a job properly and safely. If a condition is described, it cannot be assumed that the
information applies to all vehicles or that all vehicles
will have that condition.
All materials and programs described in this
magazine are subject to change. Submission of
materials implies the right to edit and publish.
Inclusion in the publication is not necessarily an
endorsement of the individual or the company.
TechConnect is published for ACDelco by Sandy
Corporation, Troy, MI.
©2009 ACDelco. All rights reserved.
For more information, refer to ACDelco bulletin #09D-110.
– Thanks to Catherine Cullins
2
Wheel and Tire Diagnosis — continued from page 1
The wheel also affects the tire’s Radial Force Measurement.
To isolate the wheel, its runout must be measured. If it meets
the runout specification, the tire
can then be
measured.
Radial Force
Measurement
must be done
under a load. The
most common
ride concern
involving radial
force variation is
highway speed
shake on smooth
pavement. A
stiff section of
sidewall will
affect the rolling
radius of the tire,
causing a vibration once per
revolution (or
in some cases,
2nd, 3rd or 4th
order inputs).
backside of the
wheel. Make sure it
does not bottom out.
The side of the cone
should uniformly
contact the center
hole inside wheel
hub (not the smaller
hub cap diameter).
If it bottoms out, the
cone may "rock" during wheel balancing.
The balancer cone
A. Wheel balancer cone
(A) should contact
B. Cone must contact hub bore
the wheel inside
inside diameter
C. Wheel
hub bore (B) for
D. Interference point
proper wheel
E. Hub cap inside diameter
retention. If the
wheel cone contacts
the hub cap inside diameter (E) and is unsupported by the hub
inside bore, the cone is not suitable and should not be used.
– Thanks to Mike DeSander and Mike Militello
Tire Sealants
Road Force Measurement
Many manufacturers are foregoing the spare tire in
new vehicles in their efforts to reduce vehicle weight
and increase fuel economy. In many models, GM
provides a tire sealant and inflator kit. The temporary
use of the tire sealant may not be endorsed by certain
tire manufacturers; however, GM has independently
validated the temporary use of the sealant when used as
described in the vehicle’s owner manual. Only the tire
sealant included in the GM kit should be used.
Tire and wheel balancer equipment with a load roller will
apply a force of up to 1,250 pounds against the rotating
tire/wheel assembly when performing a Road Force
Measurement to simulate actual driving conditions and test
tire uniformity. The equipment can measure loaded radial
runout of the tire/wheel assembly within 0.002-inch. The
measurements of loaded radial runout are converted to Road
Force Measurement in pounds, kilograms or Newtons.
Before using the tire sealant, the expiration date on the
sealant canister should be checked. There is only enough
sealant in the kit to seal one tire. After use, the sealant
canister and sealant/air hose assembly must be replaced.
Most tire manufacturers do not recommend evaluating
radial force variation until the tires have been driven for at
least 10 miles (16 km) to ensure removal of any flatspotting.
Do not use a Road Force Measurement to audit new tires.
It is intended as a diagnostic tool to minimize radial force
variation of the wheel/tire assembly.
Measuring wheel runout, and finding the low point of the
wheel (for runout) and the high point of the tire (for radial
force variation), allows the tire to be match mounted to the
wheel to achieve the lowest wheel/tire assembly radial force
variation. Place the wheel/tire assemblies with the lowest
radial force variation on the front of the vehicle.
If match mounting tires to in-spec wheels produces
assembly radial force variation numbers higher than the manufacturer’s specifications, tire replacement may be necessary.
Balancer Cones
When mounting a wheel to a wheel balancer/force variation
machine, use the wheel’s center pilot hole. This is the primary
centering mechanism; the bolt holes are secondary. Usually a
back cone method to the machine should be used.
GM Tire Sealant and Inflator Kit
Some cast aluminum wheels may not “chuck up” properly
when installed to some wheel balancers. This can lead to an
inaccurate wheel balance and result in a vibration concern.
A vehicle with a temporarily sealed tire should not be
driven more than 100 miles before the tire is repaired or
replaced. The tire pressure sensors, if equipped, also
should be inspected after sealant use for any damage
and replaced/cleaned as needed.
Prior to installing the wheel on the balancing machine,
check the locating cone for proper fit to the wheel. Install the
balancer locating cone inside the wheel’s center hole from the
3
Winter Car Care
In areas where winter driving can
involve cold temperatures, ice and
snow, special attention should be given
to certain vehicle maintenance items.
When talking with customers about
installing a new battery or new tires, or
performing cooling system maintenance
before the temperature drops below
freezing, keep these winter car care
tips in mind.
Batteries
When a battery is subjected to a
high discharge rate, as is the case with
cold-start cranking, the battery may be
completely discharged in a short period
of time due to the fact that cold temperatures slow down the chemical
reaction in the battery. Only a very
small percentage of the total active
material and electrolyte within a battery
cell can be
utilized under
colder conditions. The
result is the
battery’s
energy storage capacity
is greatly
reduced.
Furthermore,
a cold engine requires more energy to
start, with up to three times the cranking load of a warm engine.
When selecting a replacement
battery, refer to the manufacturer’s
battery recommendations. To guarantee
satisfactory performance at low temperatures, it is essential to select a battery
of sufficient size and power.
At subzero temperatures, the capacity of a typical battery at full charge is
only 45% of its capacity at 80°F.
Sometimes a battery test will show
satisfactory performance, yet the
battery will fail during service. Some
common reasons why good batteries
can fail:
• Accessories left on
• Excessive parasitic drains
• Faulty charging system
• Excessive electrical load, often
from add-on accessories
• Faulty battery connections
• Improper previous charging
• Frozen battery due to being
discharged and left in freezing
temperatures
Tires
Before winter
sets in, check
tire tread depth
and pressure.
Remind customers that
pressure in tires
drops as the
outside temperature drops.
All gases change pressure as their
temperature changes. As a rule of
thumb, tire pressure will change about
1 psi (7 kPa) for every 10°F decrease in
temperature — dropping when it gets
colder outside, rising when it gets
warmer. Tire pressure should be set to
the specified Tire Information Label
pressure at the lowest seasonal
temperature the vehicle will encounter
during operation.
During colder conditions on a vehicle
equipped with a tire pressure monitor
system, the air pressure in a cold tire
may be at the pressure where the system is required to warn the driver by
illuminating the low tire pressure light
or displaying a Check Tire Pressure
message. However, that same tire will
rise in temperature and pressure as the
customer drives, which may cause the
message and/or light to go out.
breakdown. Inspection results during a
National Car Care month revealed:
• 21% of the vehicles had low,
leaking or dirty coolant
• 11% of the vehicles had at least
one worn or unsatisfactory belt
• 4% of the vehicles needed to have
hoses replaced
Check the surge tank reservoir for a
proper fluid level. In addition, use a
cooling system pressure tester to check
the pressure cap and cooling system.
The cooling system should hold the
rated pressure for two minutes.
The pressure cap seals and pressurizes the cooling system. As the
pressure builds, the boiling point of
the coolant goes up as well. The cap
contains a blow-off or pressure valve
and a vacuum or atmospheric valve. The
pressure valve is held against the seat
by a spring of predetermined strength,
which protects the radiator by relieving
pressure exceeding the rated pressure.
To avoid a Check Tire Pressure message or warning lamp due to extreme
temperature changes, do the following:
• Use an accurate, high quality tire
pressure gauge
• Adjust the tire pressure to the
specified value when the tire
temperature is at the lowest
expected temperature. Never set
the tire pressure below the label
value regardless of tire temperature
or outside temperature
• Re-learn the TPM sensors and
adjust the tire pressure to the specified values after every tire rotation
Cooling System
The cooling system uses a coolant to
transport heat energy away from the
engine. Coolant is a mixture of water
and chemical additives. The additives
provide corrosion protection and lubrication, raise the boiling point, lower the
freezing point, and provide the chemical
buffers and sacrificial ions to limit
corrosion of the various metallic
materials used in today's engines.
According to the U.S. Department
of Transportation, coolant-related
failures are a major cause of mechanical
The vacuum valve is held against the
seat by a spring, which permits opening
of the valve in order to relieve vacuum
created in the cooling system as it
cools off. The vacuum, if not relieved,
might cause the radiator to collapse.
Replace the cap if it is not sealing or
venting properly.
To maximizing the service life of
cooling system components:
• Perform a visual inspection and a
squeeze test with your finger and
thumb of the coolant hoses as part
of a vehicle’s regular maintenance.
Remember, Electro Chemical
Degradation (ECD) occurs within
two inches of the ends of a hose
• Check for electrolysis (cause of
ECD) with a voltmeter. Any voltage
reading over 0.3 V indicates stray
voltage is finding its way into the
coolant
• Verify coolant concentration using
a refractometer, as it can work
with both ethylene glycol and
propylene glycol.
continued on page 5
4
Short-term SPS Subscription
Now Available
ACDelco now offers a short-term
Service Programming System (SPS)
subscription for GM, Saturn and Saab
vehicles.
The 3-month SPS-only subscription
is available for $275.
To subscribe:
1. Go to www.acdelcotds.com
2. Log in to the website
3. Under the TIS2Web – Service
Programming subscription option,
click Subscribe Now
4. In the TIS-SP drop-down box,
select 3 Months ($275), and fill
out the required billing information
– Thanks to Bob Stewart
Vibe PCM Calibrations Available via TIS2Web
Pontiac Vibe
programming
software and
calibrations
going back to
the 2003
model year are
now available
for download
from the GM
TIS2Web
application.
to use to download the latest Vibe calibration updates.
To access the calibrations and software programming
instructions:
1. Log in to TIS2Web
2. Click the Help menu question mark (?) icon
3. Click the Vibe Programming Application and Calibrations
in the left column.
The Vibe CUW Programming Application must downloaded
and installed before being able to download any calibrations.
New Vibe Calibration Update Wizard application
Calibrations downloaded using the CUW application are
stored on the PC and can be used on multiple vehicles.
It is no longer necessary to always replace the PCM on a
Vibe with a pre-programmed module; instead, technicians can
perform calibration updates for a number of performance concerns using the Calibration Update Wizard (CUW) application.
For additional information on downloading and installing the
Vibe software, contact the ACDelco e-Business/TIS2Web Help
Desk at 1-888-212-8959.
– Thanks to Bob Stewart
The CUW application is separate from SPS and needs to be
downloaded to the PC. Once it is set up on the PC, it is easy
Winter Car Care
— continued from page 4
• Flush the cooling system every
two years if designed with ethylene
glycol (green coolant), which reduces
the possibility of scale or harmful
sediment build-up that can decrease
cooling performance, freeze protection and hose life
• Various methods and equipment can
be used to flush the cooling system.
If special equipment is used, such as
a back flusher, follow the instructions,
and always remove the thermostat
before flushing
• Do not use conventional (green)
coolant in a system designed for
long-life DEX-COOL© because service
intervals will be reduced to two years
or 30,000 miles
– Thanks to Mike DeSander
2010 MACS
Convention Preview
ACDelco is a proud sponsor of the
2010 Mobile Air Conditioning Society
(MACS) Worldwide annual convention
and trade show being held January
19-21, 2010, in Las Vegas. This is the
30th anniversary of the convention and
several representatives from ACDelco
will be presenting the latest service
technical information.
Mike Militello from ACDelco will
conduct a seminar on Controller Area
Network (CAN) Communication
Diagnosis, highlighting technical
information and diagnostic procedures
that are related to CAN data vehicle
communications, including how all
vehicle modules and various subsystems work together.
5
ACDelco’s Bill Henderson will present the Hybrid Aftermarket Service
seminar, covering current hybrid vehicle technology and its effect on typical
aftermarket service providers, including safety, tools and procedures.
ACDelco also is sponsoring the
Paul, Paul and Ward Breakfast, featuring Paul DeGuiseppi, Paul Weissler and
Ward Atkinson, along with special
guest Bill Haas, who will talk about
the latest automotive technology and
how service centers can prepare for it.
For more information, go to the
MACS website at www.macsw.org.
– Thanks to Mike Militello
Q: How do I update the service center’s contact
information?
The TSS Q&A provides answers to
common questions received by the
ACDelco Customer Support Center.
A: For changes in the owner or service center name,
contact your ACDelco District Manager (DM). For
changes to the service center’s contact information,
contact the Customer Support Center at 1-800-825-5886,
prompt #0. The CSC can make minor updates and will
forward larger updates to the DM.
Q: Why is my service center not on the ACDelco locator?
A: The TSS program changed in 2009 and service centers
were placed in one of three levels: Red, White and Blue.
Red level shops are no longer being listed on the locator.
However, levels are evaluated throughout the year and if
a service center moves up to the White level, they will
be listed on the locator service.
Q: How do I get started with the training that is offered?
A: You can go to www.acdelcotechconnect.com and click on
the training tab. Click the sign-in button twice and then
create an account for everyone in the shop by clicking on
the new user registration button.
Both online courses
and registration for
instructor-led training
can be found on this
site along with
TechAssists.
Q: Why is my service center’s phone number different
on the ACDelco locator online?
A: The different phone number means that the service
center is taking part in the call tracker program. Although
a different phone number is listed, the service center
does receive all of the phone calls. It is a way to track
the number of calls from people finding the service
center online. The current program offers this service to
Blue Level TSS accounts only.
If you have any
questions about the TSS
program or any current
ACDelco activities, contact
the Customer Support
Center at 1-800-825-5886,
prompt #0.
Q: If I have multiple service centers, can all purchases be
combined to get to the next TSS level?
A: No, each service center has an individual account
number. Therefore, purchases made at one service
center are counted separately from the purchases of
other service centers.
Global Refrigerant Development Continues
The development of a new global
refrigerant to replace HFC-134a (or
R-134a) continues as worldwide regulations change and deadlines are set.
The European Union, Japan and
United States are all reviewing new
mobile air conditioning regulations that
require all-new vehicles in the near
future to use a mobile A/C refrigerant
with a GWP (Global Warming Potential)
below 150, although there is not agreement on any one refrigerant for worldwide use in all countries. The Japanese
government, however, recently did
approve the use of a new refrigerant.
Current mobile air conditioning systems using HFC-134a have a GWP of
1,410. Two of the potential refrigerants
currently being tested include R-744
(CO2) and HFO-1234yf, both of which
have a much lower GWP.
Classified as a greenhouse gas,
CO2 obtained as a by-product of other
industrial processes is actually the least
damaging refrigerant possible. R-744
has a GWP of 1.
The service industry would be significantly affected by the use of R-744,
which requires higher operating pressures and more complex A/C systems.
As a result, service centers would need
specialized training and equipment to
handle the high pressures as well as
adherence to strict safety procedures.
Operating pressures, chemistry and
other qualities of HFO-1234yf — developed jointly by Honeywell and DuPont
— are similar to those of HFC-134a.
This would enable manufacturers to use
the new refrigerant with almost all of
the industry’s existing mobile A/C technology. HFO-1234yf has a GWP of 4.
One problem with HFO-1234yf is
that it is classified as “mildly flammable,” meaning that it can be ignited and
it will burn. However, the conditions
required for ignition are very specific
and the flame temperature is relatively
low. The refrigerant has undergone
significant testing by many independent
groups, including the SAE International
Cooperative Research Program, for
both safety and effectiveness.
6
Honeywell recently announced that
HFO-1234yf had been examined for
import and use by several Japanese
regulatory authorities. Japan’s Chemical
Substances Control Law mandates the
evaluation of new chemical substances
before they are manufactured or
imported to Japan. After receiving the
study results, the government of
Japan will permit the refrigerant to be
imported without restriction and will
not impose any controls or special
monitoring on the chemical.
Japan’s approval of HFO-1234yf is
seen as a significant step toward
developing a global refrigerant that can
be used worldwide and still comply with
each nation’s individual environmental
and safety laws.
For more information on the latest air
conditioning technology, contact your
local ACDelco distributor to learn when
the ACDelco Emerging A/C Technology
and Service seminar will be held in
your area.
– Thanks to Mike Militello and MACS
The following technical tips provide repair information about specific conditions on a variety of vehicles. If you have a tough or unusual
service repair, the TSS Technical Assistance Hot Line can help. Call 1-800-825-5886, prompt #2, to speak with a technical
expert with the latest OEM information.
Manual Transmission
Blocked Shift or
Difficulty Shifting
2003-2007 Saturn ION, 2004-2007
Saturn VUE, 2005-2010 Chevrolet
Cobalt, 2005-2009 Pontiac G5, and
2006-2010 Chevrolet HHR — equipped
with a Getrag manual transmission
(RPO M86
or MG3)
The manual
transmission
may exhibit a
hop-out or
blocked shift
of 1st, 3rd and
5th gears or
difficulty shiftDislodged roll pin
ing. The shift
lever roll pin may back out and contact
the shift cover during a shift event,
which can cause an incomplete,
blocked shift or difficulty shifting the
transmission.
Prior to any internal transmission
repairs, inspect the shift cover and lever
to determine if the roll pin has backed
out and is dragging on or contacting the
housing. If roll pin contact is evident,
then the shifting difficulty may not be
an internal transmission condition.
If the shift cover shows witness
marks from contact with the roll pin,
replace the complete shift cover
assembly. Do not replace the transmission for this condition.
If the roll pin is not dislodged, follow
the appropriate Service Information
diagnostics.
Driveline Noises in 4WD
2009 and prior Chevrolet and GMC
light-duty trucks and SUVs equipped
with 4WD, 2009 and prior HUMMER
H2 and H3
These vehicles may exhibit a groan,
growl, or moan noise when operating
in 4WD Lock.
The noise may be due to a vibration
that is heard or felt as a result of the
front axle being excited to resonance
at its natural frequency. This is a
combination of the transfer case chain
link frequency, engine firing frequency,
tire circumference variation, and
various other tolerances built into the
4WD system.
A groan, growl or moan noise on
deceleration while in 4WD Lock is
also the result of loading the transfer
case chain, which is an operating
characteristic. This is just one example
of a transfer case link frequency as
noted previously.
On certain models, such as 3/4 -and
1-ton vehicles, tire pressures can vary
from front to rear based on the manufacturer's specifications. Refer to the
vehicle’s Tire Information Label for tire
pressure specifications.
The difference in tire pressures
affects the rolling tire circumference
from front to rear, which can increase
driveline noise while in 4WD.
For test purposes on vehicles with
different tire pressures, drop the tire
pressure in the rear to match the front.
If the noise is reduced or eliminated,
this confirms the difference in tire
pressures from front to rear can affect
the noise when operated in 4WD. Set
the rear tire pressure back to the
manufacturer's specification.
No repairs are recommended for this
condition. For more information regarding driveline noises while in 4WD, refer
to GM bulletin #01-04-18-001F.
Steering Wheel Vibration
1996-98 Ford Crown Victoria, Mercury
Grand Marquis, Lincoln Town Car
A vibration or buzzing noise may be
heard or felt in the steering wheel on
right turns at engine RPMs between
590-1100. This condition may be caused
by valve resonance and power steering
pump pulsations.
Replace the power steering pressure
hose to dampen the noise. A new
power steering hose bracket is attached
to a stud on the engine, between the
crankshaft pulley and power steering
pump pulley.
Also check the fluid level in the reservoir, verify there is no air in the power
steering system, and make sure that
the steering shaft does not contact any
other lines or components.
Slipping Clutch Conditions
2004-09 GM passenger cars or lightduty trucks equipped with a gasoline
engine and manual transmission
7
The Service Engine Soon (SES) light
may illuminate and, using a scan tool,
DTC P0502 (Vehicle Speed Sensor
Circuit Low Voltage) may be found
stored in the PCM.
If no cause for the DTC can be found
after following the appropriate Service
Information diagnostics, the condition
may be customer induced.
Supporting data may be found in the
freeze frame information stored with
the DTC. Review the scan tool data
parameters: Calculated Engine Load,
Engine Speed, Output Shaft Speed
Sensor and Clutch Pedal Position.
Inform the customer that excessive
slipping of the clutch with the vehicle
stationary or moving at low speeds may
cause this DTC to set. This is considered normal vehicle operation.
No Power Steering Assist
Dodge Ram 2500
When replacing the power steering
pump, properly torque the mounting
bolts to specification during pump
installation. Do not use an air ratchet.
This is a vane type power steering
pump with the mounting bolts going
through the housing. If the bolts are
over-torqued, they may compress the
front and rear cover against the vanes,
leading to severe wear, metal debris in
the system, and eventual pump failure.
Diagnostic Assistance
For free technical diagnostic
assistance and product information
regarding specific ACDelco products,
contact these toll-free information
hotlines staffed by ASE-certified
technicians:
Brakes – 1-888-701-6169 (prompt #1)
Chassis – 1-888-701-6169 (prompt #2)
Clutches – 1-888-725-8625
Lift Supports – 1-800-790-5438
Shocks – 1-877-466-7752
Starters and Alternators –
1-800-228-9672
Steering – 1-866-833-5567
Wiper Blades – 1-800-810-7096
Go to www.acdelcotechconnect.com and click the Training tab to log in to the ACDelco Learning Management System (LMS).
New Training
Current Instructor-Led Training
The following ACDelco training programs have recently been
made available via the LMS:
ACDelco’s Instructor-Led Training (ILT) courses provide
hands-on instruction on the latest automotive systems. The
following ILT courses are currently being held at training
center locations around the country. Click the Schedule link on
the LMS Menu to search the latest training schedule for
courses held in your area.
S-EL06-52.01WBT – GM Global Electrical Systems
The new global format of service diagnostic procedures,
including the common circuit types and functions used in GM
electrical architecture, are covered in this course along with
the types and characteristics of serial DATA circuits. In addition, the course reviews the types of ground and voltage
circuits, the types of signal and control circuits, and common
circuit diagnostics using a digital multi-meter and scan tool.
Course Number
Course Name
S-AC07-02.01ILT
Automotive Air Conditioning: Advanced
Refrigerant System Diagnostics
An introduction to the new Global Diagnostic System
(GDS), this course highlights the software and hardware
components and their operation. It covers key features of the
Global Diagnostic System, such as administration and navigation procedures, characteristics of diagnostic packages, the
operation of the vehicle identification and home screens, and
diagnostic functions.
S-AC07-03.01ILT
HVAC Control System Operation and
Diagnostics
S-AC07-06.01ILT
Toyota HVAC
S-AC07-07.01ILT
Chrysler HVAC
S-SS04-07.01WBT – Driveline Axles and Propshafts
S-BK05-01.01ILT
Braking Systems
S-EL06-04.01ILT
Body Control Systems Diagnostics
S-EL06-04.02ILT
Network Communication Diagnosis
S-EL06-10.02ILT
Electrical Power Management
S-EL06-11.01ILT
Automotive Electrical Circuit Diagnosis and
Repair
S-FN00-05.01WBT – Global Diagnostic System
The characteristics, operation, and diagnostic and service
procedures of front and rear axles and propshafts are covered
in this course, including propshafts, universal joints, front axle,
rear axle, differential assembly, and electrical systems. It
focuses on diagnostic and service procedures.
S-SS04-08.01WBT – GM Chassis Control Systems
The basics of several commonly used suspension types are
reviewed in this course. It covers suspension system types
and their operation, air suspension components and operation,
level control (including mechanical and electrical controlled
damping), tire pressure monitoring system variations and
operations, alignment types (including characteristics,
components and operation), and commonly adjustable and
non-adjustable angles.
S-EL06-12.01ILT
Hybrid Technology and Service
S-EP08-02.01ILT
Engine Performance: Computer Controls and
Ignition System Diagnostics
S-EP08-20.01TAS – 1.6L and 1.8L Engine
Timing Procedure
S-EP08-03.01ILT
Engine Performance: Air Induction and Fuel
System Diagnostics
S-EP08-04.01ILT
Engine Performance: Fault Monitoring and
Emission System Diagnostics
S-EP08-05.01ILT
Engine Performance: Advanced Drivability
Diagnostics
S-EP08-20.01ILT
Toyota Engine Performance
S-EL06-46.01TAS – U-Van Power Sliding
Door Repair
S-EP08-21.01ILT
Chrysler Engine Performance
This TechAssist addresses several issues related to the
operation of the automatic side door on 2005-2008 Chevrolet
Uplander, Saturn RELAY, Buick Terraza and Pontiac Montana
vans. It includes diagnostic and repair information on the
automatic side door.
S-EP08-81.01ILT
Duramax 6600: Diesel Engine Performance
S-SS04-01.01ILT
Vibration Correction Diagnostics
S-ST10-01.01ILT
Supplemental Restraint Systems
This TechAssist shows how to perform the timing procedure
on the 1.6L engine in the 2009 Chevrolet Aveo and 2009
Pontiac G3, and also on the 1.8L engine in the 2008-2009
Saturn ASTRA.
S-EL06-45.01TAS – Side Object Detection System
This TechAssist presents an overview of the operational
characteristics and diagnostic strategies for Side Object
Detection Systems.
TS-PU-0011-09
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