W124 M104 - Trouble Shooting Throttle/TLLR Wire Harness
 

Hi Folks,

Im hoping those of you more familiar w/ the wiring on these cars can help. I want to evaluate the harness that connects to the throttle body and the TLLR module and see if there are any shorts or breaks in the wire. Is there an easy way to do this?

Was thinking I can check continuity across pins that share a circuit or check continuity to ground or something of the sort, but I dont know :confused:

Thanks!

See if it has a updated throttle actuator. It’ll have the date made sticker on it. I think you want 2000 and newer. If not updated then most likely the looms of wires are all bare wires with insulation that turned to dust. Could slice open the outer black rubber insulation on the throttle body and check it out

there's a youtube video,on rewiring throotle

Im talking about the harness that connects to the throttle and goes through the dash into the computer in the passenger floor boards. It connects near the battery too, or are you talking about the main harness?

Same stuff., check the date on the tag near the main connection by the battery. Unravel the tape in some spots. You’ll see right away if you got a problem

oh that harness is definitely original...guess Ill have to figure how to feed it through the dash and replace lol

It's very, very rare that harnesses "inside" the body of the car have problems. The killer is the combination of high heat cycling (under the hood) vs soy based wire insulation. High heat wins

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Is there a way to test that, shy of cutting it open? I wonder if I f-ed up the harness when pulling the throttle off the car a couple of times but I would like to test instead of just throwing another part at it ^^

I don't recall any "test" other than visual on the harnesses. If you've been jerking around with/on original harnesses, there is a stronger than strong chance that it's in bad shape. Start looking for replacements and don't drive the car if possible. Wiring that is already compromised can lead to damage in the control units.

Check your part numbers and start looking for replacements. Any harness/actuator with a build date, post 1998 will be good.

Good luck

Jayare

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