29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
Re. iring the Right Side Electronic Throttle Actuator (ETA)
The V12 engine in this car has two Electronic Throttle Actuators (ETA). They are electrically
operated. They control the amount of air that is drawn into the engine. The right side ETA controls
the left side bank of cylinders, and the left side ETA controls the right side bank of cylinders. The
right side ETA is commanded by the left side ETA. Although the left side ETA has cables from the
gas pedal attached to it, the primary means of actuation is not mechanical. There is a potentiometer
linked to the gas pedal that functions as a position sensor. The position of the gas pedal is
transmitted electrically via wires to the onboard computers. From this info, the computers calculate
how to actuate the ETA's. It is a drive-by-wire system. This is how the car's traction control can
decrease engine speed if necessary, regardless of how hard you press on the gas pedal. I will not go
into the workings of these devices here. Many more details on ETA function can be found on
several Mercedes Benz Forums.
Mercedes Benz used a wire
insulation material that was
unsuitable for the hightemperature environment of an
engine compartment. Rumor has it
that it was developed to be
biodegradable in an effort to be
environmentally conscious. While
the intentions were good,
unfortunately the insulation
degrades in the car. This seems to
be the case with many different
types of MB models around 1992
to 1995. The problem was
corrected in year 1996 and on.
The insulation begins to break
down and crack. If the problem is
not addressed, the insulation will eventually fall off the wires and cause short circuits. At the least,
this could cause all sorts of caution lights to light up on your dashboard. It is also the cause of many
Traction Control and . Limp Home problems or engine stalling. At the worst, it could damage very
expensive electronic components or possibly cause an engine fire. In my car, I got an intermittent
Check Engine (CE) caution light. Pulling fault codes from the onboard computers did not really
point to anything specific, but one recurring fault code was Faulty Electronic Throttle Actuator.
One way to determine the condition of insulation quality is to do an Insulation Breakdown test. To
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29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
do this requires specialized equipment though, something that most people don.t have in their
garage. In addition, there are some very sensitive electronic components within the ETA that could
be damaged by performing such a test. The best way to examine the condition of the wires in the
ETA's is to remove the ETA s from the intake manifold and inspect the wire visually.
This page describes the Right Side ETA repair project in detail. These basic guidelines can be used
to repair the Left Side ETA as well, but keep in mind that the wiring will be different than that
shown for the Right Side ETA. In addition, the Left Side ETA has the throttle cable connections.
These instructions do not cover the disassembly. It is fairly straightforward. If you do the Left Side
ETA, I strongly recommend taking digital pictures as you go. That way you have a record of where
that "extra" screw is supposed to go. The Left Side ETA cables have springs attached to the
linkages...DON'T lose them!
One thing you should be aware of is that there are potentiometers in these units that can also fail.
This project does not address failed potentiometers. Check out Jim F's web page for further details
on that.
It is assumed that you know how to solder well.
If not, find a friend who can to help you.
Parts / Materials Needed:
Military grade wiring per M22759/11. It is rated for a conductor temperature of 200° C, and
the insulation is able to withstand a constant temperature of 260° C. There are three different
gages of wires that needed to be replaced. The original gages are metric in size, and are .35,
.75, and 1.5 mm in size.
For .35 mm, I used 26 gage
For .75 mm, I used 20 gage
For 1.5 mm, I used 14 gage
This means that you will need;
For Right Side ETA (US Passenger Side)
Two 48" lengths of M22795/11-14
Two 48" lengths of M22795/11-20
Four 48" lengths of M22795/11-26
For Left Side ETA (US Driver Side)
Two 48" lengths of M22795/11-14
Two 48" lengths of M22795/11-20
Seven 48" lengths of M22795/11-26
The color designator is also a number, and is placed at the end of the wire and gage
number. So for example, M22759/11-26-6 is a 26 gage wire with blue insulation.
Possible Wire Suppliers:
Whitmor / Wirenetics
27737 Hopkins Ave
Valencia, CA 91355
800-822-9473
Sea Wire and Cable, Inc.
P.O. Box 647
451 Lanier Road
Madison, AL 35758
800-633-7210
Galaxy Wire and Cable
420 Babylon Road, Suite D
Horsham, PA 19044
888-425-4454
RDS Wire & Cable
225 E. Gardena Blvd
Carson, CA 90248
310-323-7131
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29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
Dearborn Wire
250 W. Carpenter
Wheeling, IL 60090
847-459-1000
Sheathing
Supplier:
Varflex
512 W. Court Street
Rome, New York 13440
Sheathing Data
I used Varflo (size 3), which according to their literature is good to 130. C. I
personally tested it to 190 C, and it withstood the temperature without any
problem.
Raychem Heat Shrink tubing, 1/2 inch DR-25.
Adhesive / Sealant
Dow Corning 3145 RTV Gray (Room Temp Vulcanizing)
MIL-A-46146
Available from:
Ellsworth Adhesive Systems
Germantown, WI
800-888-0698
Approximately $18.00 for a 3 ounce tube.
Tools needed:
T20 Torx bit
5 mm hex key
Pliers
10 mm socket, ratchet wrench, and various length extensions
Flat blade screwdriver
Philips blade screwdriver
Wire cutters / strippers
Soldering Iron, along with flux and solder.
Disconnect the air temp sensor from the intake runner. Gently bend the plastic retaining tabs up out
of their locking slot, and rotate the sensor 90 degrees to pull it straight up and out.
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29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
P.
R
'
.D
10
140repair.com/ETA_Re ire.htm
.G
,
.
.T
'
. N #2
.D '
.
4/26
29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
Undo the t. o spring clips from either side of the air filter bo
Flo (MAF) Sensor.
140repair.com/ETA_Re ire.htm
here it connects to the Mass Air
5/26
29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
Disconnect the MAF connector b. rotating it counter clockwise when viewed from the wire side.
Move the connector and wire bundle out of the wa .
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29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
Lif. he ai fil e bo p o clea he d ha hold i in place. Yo ma ha e o gen l
i i o
di lodge i f om he MAF. Again, make
e he in ake f nnel i fo a d eno gh o p o ide
clea ance.
Loo en he band clamp on he bbe in ake nne he e i ma e i h he MAF ing a Phillip
c e d i e . Gen l
i he MAF o b eak he eal be een i and he bbe in ake nne .
CAREFULLY p ll he MAF o of he bbe in ake nne . Do no damage he c een on ei he
end of he MAF, he a e delica e. Bag and eal he MAF in a ip-loc bag o p e en con amina ion.
Ai Fil e bo and MAF emo ed.
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29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
Loosen the band clamp on the rubber intake runner where it mates with the ETA using a Phillips
screwdriver. Gentl. twist the intake runner to break the seal between it and the ETA. Pull the
rubber intake runner out.
Rubber intake runner removed.
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Re iring the Electronic Throttle Actuator in a W140 Mercedes
Remove the EGR vacuum module from the side of the intake manifold using a 10 mm socket.
Disconnect the red vacuum hose from the diaphragm below the ETA. Position this module out of
the wa. .
Remove the clip securing the ETA wire bundle to the frame, as well as the vacuum line with the
bend in it from the ETA.
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29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
Remo. e he ho e clamp holding he
140repair.com/ETA_Re ire.htm
bbe ho e going o he bo om of he ETA
ing plie .
10/26
29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
I c. one ho leng h off of he he ke fo loo ening and igh ening he cap c e
ea ie and fa e o e once he cap c e a e loo ened.
b hand. M ch
U ing he 5 mm he ke , emo e he 4 ocke head cap c e holding he ETA o he in ake
manifold. Yo ma ha e o gen l "pe ade" he hea hield a a f om he bod o ge eno gh
clea ance fo he he ke a ho n.
Make
e o a e holding he ETA ec el
140repair.com/ETA_Re ire.htm
hen p lling o
he la bol . Don' le i fall.
11/26
29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
Remove the ETA from the intake manifold.
The passenger ETA connector is located on the passenger side wheel well underneath the plastic
removable cover. Flip the ETA connector retainer clip up, and swing it out of the wa. . Pull the
ETA connector out of the mating connector. It's in there prett tight.
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12/26
29.5.12
Ca.ef
be
ed
Re iring the Electronic Throttle Actuator in a W140 Mercedes
ea d
he ETA i e b
f he ca .
de
f he
di g a ea. The ETA i
Re
e he a ge c e f
he ETA b d
i g he T20 T
bi . Y
he c e a a f
he ETA b d . The e i a i ha
bab f c i
ha a e i diffic
e
e he c e ( ed a
). I i b ea
he
b ha i
a
be .
L
c e a he i e . If he i
e i e he ETA. If he i
ai
a i i c ac ed i e he e h
g d,
'e
bab i c !
I
d ha a d
he hea hi g i
iei
g e ha if he
bab OK
.
ai
i ide he Ac a
ab e
a ha e ge
a a a e i dica
e
e he c e ,
he e,
i OK, he i
i ha e
ai
i hi
S a i a bac
ge he . Ma e
e he b ac ea
he face f he ca i g i i ace bef e
ed
he c e . Y
i eed a e ga e f be ee he ETA a d i a e a if d. I i
MB P/N 104 141 07 80. C i a
d US $1.50.
140repair.com/ETA_Re ire.htm
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Re iring the Electronic Throttle Actuator in a W140 Mercedes
Close-up of cracked insulation on wires.
There are some smaller gage wires that have a different t. pe of insulation on them. The colors of
these wires are pastel. You can see them under the other wires. These wires come from the
potentiometer on the other side of the ETA. These wires were OK on m vehicle, and did not need
to be replaced. These instructions do not include this step.
Here is a picture of the Pastel wires after the other wires are cut awa . The insulation on these
wires was still good, so the were left alone.
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29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
!! You should take ver. good records/notes/pictures of our particular unit
BEFORE ou start cutting wires !!
The . i e hea hing on he ETA i a ached o he ETA bod . I'm old o can p he e aining ing
o of he ETA, hich ill allo
o o p ll o he en i e i e b ndle. I decided no o a emp o
emo e he en i e leng h of hea hing f om he ETA, b o lea e abo 6 inche of he hea hing
in ac . I c h o gh he i e b ndle and hea hing abo 10 inche f om he e i poin on he ETA.
No e ha he Lef Side ETA i ho n fo ill a i e p po e a I do no ha e a pho o of he Righ
Side ETA. The concep i he ame ega dle of he ide being o ked on.
S ip back abo
4 inche of he hea hing o e po e he inne
140repair.com/ETA_Re ire.htm
i ing.
15/26
29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
You will see some solid black wires in the bundle. These are not wires, but simple strands of
plastic. M. guess is that the are there to create a good tight pack for the wires inside the sheathing.
Note the cracks in the insulation.
Cut the wires needing replacement close to the circuit board. DO NOT cut the Pastel wires.
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Re iring the Electronic Throttle Actuator in a W140 Mercedes
Pull one wire at a time from the sheathing. Pull the wire either from the circuit board side, or the
cut sheath side, whichever end is easier. The first wire will be the most difficult. The wires are
packed tightl. within the bundle. As ou pull more wires out, the become easier to remove.
Continue until all wires within the sheathing are pulled out. Note that the Pastel wires are all within
the ETA, the do not continue out of the ETA through the sheathing.
Carefull remove the o-ring from the connector.
Now comes a trick part. You need to disassemble this connector. It is a multi-piece connector, but
it is heat or solvent welded together. It can be taken apart with care and patience.
First cut through the wire bundle as close as ou can to the back of the connector.
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29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
E. amine he connec o o find he mold line be een he o hal e . U ing a ha p ne
ili a o
blade o X-Ac o knife, epea edl co e he mold line on bo h ide of he connec o n il he c i
abo 1/16 h of an inch deep. Yo MUST follo he mold line a clo el a po ible in o de o
pli he connec o afel .
Go lo l and ca ef ll , do no
gen le c .
o make oo deep a c
Place he connec o in o a ocke ha
ill
ppo
a one ime. I i be e o make man
he connec o
Place a ili a o blade on o he mold line, and lo l / ca ef ll
a
o pli he hal e apa .
ec el .
ap i
i h a hamme
Do no p h he blade f he han he la ge diame e of he connec o . Once o
connec o hi fa , emo e he blade and con in e o ca ef ll p he hal e apa
ce di e.
n il i
pli he
i h a fla blade
Again, go lo l , and mo e he blade o diffe en a ea o ge he hal e o pli
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Re iring the Electronic Throttle Actuator in a W140 Mercedes
The connector halves apart.
Carefull. pr out the inner barrel.
Remove remnants of sheathing from connector halves.
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Re iring the Electronic Throttle Actuator in a W140 Mercedes
Move the 2 locking tabs out and awa. from the inner piece as shown, and pull the gra pin holder
up and out.
At this point ou can pull the connector pins out of the pin holder.
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29.5.12
P. ll he pin o
Re iring the Electronic Throttle Actuator in a W140 Mercedes
in he di ec ion of he a o
.
De- olde he old i e f om he pin . Keep he pin a e
olde f om he pin
ing a olde p mp o olde ick.
ill e e hem. Remo e all he old
No ice he b o n e id e a o nd he olde join . Thi i fl ha a no cleaned off p ope l
af e olde ing. In ome ca e , hi can ca e co o ion of he olde join .
De- olde he emainde of he c
i e f om he ci c i boa d. Do no keep he olde i on ip on
he boa d an longe han o ha e o o o can damage he ace on he boa d. Again, emo e
all he old olde f om he boa d.
Remembe o e a fl
i able fo he olde o a e ing, and o clean he olde join
ho o ghl
ing I op op l Alcohol and a iff of b i le b h.
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29.5.12
Re iring the Electronic Throttle Actuator in a W140 Mercedes
An examination of the inner surface of the cover shows residue, probably insulation that fell off and
into the gear-train, and was ground up.
There was also some residue in the gear teeth.
Clean all this residue from the various parts.
Now we can begin rewiring the ETA with new wire.
I used Military grade wiring for this as it is can withstand high temperature. The wire number series
is M22759/11. It is rated for a conductor temperature of 200. C, and the insulation is able to
withstand a constant temperature of 260 C. There are three different gages of wires that needed to
be replaced. The original gages are metric in size, and are .35, .75, and 1.5 mm in size.
For .35 mm, I used 26 gage
For .75 mm, I used 20 gage
For 1.5 mm, I used 14 gage
This means that you will need;
Two 48" lengths of M22795/11-14
Two 48" lengths of M22795/11-20
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Re iring the Electronic Throttle Actuator in a W140 Mercedes
Four 48" lengths of M22795/11-26
The color designator is also a number, and is placed at the end of the wire and gage number. So for
example, M22759/11-26-6 is a 26 gage wire with blue insulation.
I chose to use different colors to help keep the wires identified. I did have to use the same color
code for both wires for the motor as I was not able to find 2 different color codes in this size. Note
that you do not have to use different color wires. All wires can be the same color as long as you
identify them correctly when soldering them in place. I do recommend that different colors be used
as it helps keep them easily identified.
Note that the color code listed below is from MB wiring diagrams.
I noticed that the wire colors in m. Left Side ETA did not match this.
You should take ver good records/notes of our particular unit BEFORE ou start cutting
wires.
Cut the wires to a length of 32 inches (. 81cm). Strip the insulation from the ends of the wire
approximately 1/4 inch (6 mm). Do not cut or knick the wire strands while stripping the insulation
off. Tin the stripped ends of the wires with solder.
Left Side ETA (US Passenger Side)
Board Location
Connector Pin Color Code
Right Side ETA (US Driver Side)
Wire Gage Board Location Connector Pin Color Code
Wire
Gage
Motor (+) terminal
4
BL/YE
14
Motor (+)
terminal
4
BK
14
Motor (-) terminal
11
BK/YE
14
Motor (-)
terminal
11
BL
14
b
3
VT/YE
26
k
12
WH/BK
20
c
14
VT
26
j
13
WH/GR
20
k
12
GY/BL
20
c
14
GY/BK
26
e
9
VT/WH
26
g
2
RD/YE
26
g
7
VT/GY
26
b
3
GY/RD
26
i
5
GY/YE
20
f
10
GY/GR
26
h
6
BL/YE
26
i
8
BR/WH
26
e
1
RD/WH
26
A big Thank You goes to our MB friend Philippe for getting me details on the Right Side ETA wiring connections.
Thanks!
Cut a length of wire sheathing 20.5 inches long, and slip it over the new wires. Butt the end of the
sheathing up against the original sheathing. Place a 3 inch length of 1/2 inch DR-25 Raychem Heat
Shrink tubing over the sheathing. Do no. shrink it in place yet. Note that this photo shows the
tubing shrunk.
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23/26
29.5.12
Solde. one end of each
Re iring the Electronic Throttle Actuator in a W140 Mercedes
i e in o a connec o pin. Make
e o ha e a good olde join .
Once all he i e a e olde ed in o he pin , a in e ing he pin in o he pin holde po ion of he
connec o a ho n pe he able abo e.
P h he pin in o each e pec i e lo , again making e o ha e he igh loca ion fo each
Make
e he a e f ll in e ed, o o ill no be able o ea emble he connec o .
i e.
Af e all pin a e in e ed, in e he pin holde back in o he ba el po ion of he connec o . I m
be p ope l aligned o e-in e i . Make
e he pin holde ea f ll in o he ba el. Yo ma
ha e o pla a o nd i h he pin o align hem in o he hole of he ba el. Thi can be diffic l .
Make
e all pin a e napped f ll in o hei lo , o o ill no be able o ea emble i .
Po i ion he ne hea hing app o ima el 1 inch f om he back of he connec o ba el, and hea
h ink he Ra chem hea h ink bing in place ing a hea g n. Thi ill eal he ne and old
hea hing oge he , and lock he ne hea hing in place.
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Re iring the Electronic Throttle Actuator in a W140 Mercedes
C. a he i ide
fb hc
ec
ha e
i g ea a
/ adhe i e
he e i dica ed b
he b e a ea .
N e ha he ic e h
he d i i g. I d
ha e a h
f he e
i i g a hi age.
The e
ii g
d b i
e e d a he c
ec , a d he e hea hi g
d be aced
e he e
ie
i hi
e i ch f he bac
face f he i h de .
P ace he c ec ba e i
e
ea ed each he .
A
e f he c
ec
ha e ,
a e
e ha he hea hi g i aced i ide he c
ded b ea a . We d ' a
a e ge i g i
a i g
e he
ai gg
ec ha e , a d i c
he i e b d e.
e ae
ee
A e b e he he ha f f he c ec ba e , a
a i g e i i i ed
e . Ca
he
ha e ge he , a d i e ff he e ce ea a ha
ee e
. Le he c
ec d /c e f
bef e ha d i g. I
da
5 f da a
e
f hi ea a
c ed e
he a
e ed. I c e
i g h idi i he ai . E e a i g e e a e, b i g i h a fa
i
acce e a e c e.
Y 'e
ead
e-i a he ETA
i a , ee i g i a a f
he e ha
cab e f he bbe i a e
e
a
he ca . Ma e
a if d. A e
h gh i .
O ce he ETA i i a ed a d e-c ec ed
ETA " e ea " id e a d f
h
e
ii
i'
.
ai gc
e
e he ETA i e b d e a
e ha he e i a fficie
i he
ec
,
i
eed
a
he
NEW " Relearn" Proced. re!
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Re iring the Electronic Throttle Actuator in a W140 Mercedes
-Start and bring engine to normal temp, 80 deg C
-Stop engine and move ignition ke. CW to #2 position w/o starting engine
-Wait for basic training sequence/ protocol. ETA will hum, and ou will hear actuator clicking.
Wait for all sounds/noises to end completel !
-Now, without turning ke off, continue moving ke C/W and start engine.
-Operate the vehicle for 30-40 minutes without turning off the engine, bring speed up to or over 65
mph if possible. Operate in a variet of conditions.
-Once time period is over, return to secure parking spot and park, DO NOT turn engine off... allow
to idle for 15-20 minutes minimum!
-When time period is over, turn engine off.
-Congratulations, our ETA has been correctl put through the Mercedes Ben Engineering (Slang:
Relearn)" Operational Sequence for 119 and 120 power plants.
These instructions are courtes of Robert Ohlings EE, ME, AES and Hibbo (Dutch) Ohlings .ME,
PE, AES. Both of these gentlemen are retired Mercedes Ben Engineer and
Diagnostic Technicians.
Thank . ou Robert and Hibbo!
If all has gone well, our engine should be running well. Sleep well knowing that there are no
electrical short-circuits in our ETA's future. Congratulations on a job well done!
I found all the diagrams I needed with m Alldatadi .com subscription. If ou sign up for the
service using the link below, I receive a small commission which helps me cover the costs of
administrating m site. Thanks!
A. da a i
i g a S ecia f
V12 Ube A e Fa
!
1 Yea S b c i i
f
$19.95! $7.00 Sa i g !
3 YEAR S b c i i
f
$29.95!
E e P
C de "POWER" ( e
a i
a
)
If ou can't see the Alldata image above, click here.
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