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CARBON FIBER/FLAT BLACK VINYL WRAPS
Many owners of 1992 to 1995 Mercedes Benz have problems with throttle bodies, also known as electronic throttle actuator or ETA. Almost all ETAs problems caused by shorting wiring inside ETA loom. On this page you find common symptoms of faulty ETA and explanation of my repair service.
ASR (anti slip reduction) equipped vehicles enter into Limp mode with ASR and ABS (in some cases) warning light illuminate on the dash . Symptoms: no acceleration when depressing gas pedal until half way down, no power at acceleration, RPMs raise and lower chaotically, idle is higher than normal, ABS and ASR warning lights are on (ASR equipped cars), cruise control doesn’t work, doesn’t keep preset speed, or shuts off. Transmission shifts at higher RPMs unless you let go off the gas. Throttle linkage is connected to kick down valve in the transmission and keeps it in gear while gas pedal is depressed.
Cars that are not equipped with ASR option have very same symptoms but engine accelerates more or less normal, idle is higher than normal and can raise and lower by itself, cruise control doesn’t work, ABS light can illuminate on dash but not all the time.
In both ASR and non-ASR cars transmission engages harsh due to higher than normal idle speed.
Some very few throttle bodies are not repairable due to wear. They have to be replaced. But most have failing wiring that short out. Those can be repaired replacing deteriorated wires with new ones. In some cases shorting wires burn E-gas computer that will need to be replaced after rewired ETA installed back into the car. It is suggested to plug ETA to the car to test before installation.
First ETA rewire I did in my 1992 500SEL W140. Original wires didn’t show severe shorts but they had lots of cracks in insulation, car went into Limp Mode from time to time. Back then (around 2006 or so) Mercedes used to sell replacement wiring pig tale for throttle actuator. It was available for pancake style flat plug with turn lock found on 92 and 93 model years. Dealers do not sell that replacement part anymore. There was never replacement wiring harness available for barrel type connector found in 94-95 models.
It took some time to remove throttle actuator. On the bottom of this page you will find few videos where I talk about my experience with removal and installation of ETA into 94 SL500. There are two vacuum hoses that need to be replaced along with actuator to intake gasket. 6 cylinder motors are slightly different. ETA sits under intake on drivers side. V12 motors have two ETA: primary with linkage on driver side and secondary without linkage on passenger side. And V8 motors have ETA in the center off the motor between intake, right under mass air flow meter. And there is no need to remove intake on either motors. On V8 motor space is very limited but there is a way to work ETA out.
On 96-up V8 and V12 vehicles ETAs are different. They don’t have pigtails anymore and main harness plug in directly into ETA. E-class and C-class vehicles used pigtail ETA until 97. These ETAs are known to have biodegradable insulation on wiring that crack and fall off.
All rewiring I offer are done with military grade Teflon coated wiring. Plastic expandable sleeve is used to run wires in. Plug is cut open, each terminal removed and new wires soldered directly to them. I also reuse OEM plastic bushing/seal that wires fed through on ETA housing. Silicone is used to seal case cover, plug, and bushing at wiring point of entry. Some grease is applied to gears for lubrication while covers are off. Plug is glued together with high strength epoxy. On videos I used heat resistant cloth tape. To create cleaner look to finished ETA plastic expandable sleeve is used from now on. Please see some pictures on the bottom of the page for updated look.
I have recorded values for both ASR and non ASR ETAs. They differ slightly but potentiometers values are same as on video below for both ETA models. I bench test all ETAs prior to rewire to make sure that internals are fine and problem is limited to bad wiring.
If you experience problems with your throttle body due to broken insulation, contact me and I will be able to rewire your ETA. New actuators can be as much as $1400. And it doesn’t make sense to buy used ones as they use same biodegradable wiring that can fail pretty fast. Even if ETA worked fine in the car it came from, wiring fails during ETA removal as loom gets bent and twisted a lot. If I cannot repair yours, I only charge for shipping. For rewire I charge $270 plus shipping and PayPal fee (if paid with PayPal).
Feel free to contact me with any ETA questions you have.
Best regards,
Victor
