P1128 Throttle Control Motor Malfunction

[Maingear]

Removed and inspected throttle body components. Cleaned and reinstalled. Worked fine for about a month.

on the 5th of July, P1128 popped up again. I have the manufactures maintenance manual volume 1 and followed DI-117 with no results. Removed Throttle Control Motor (TCM), Installed new TCM ($280). It takes a couple of minutes for the computer to throw the code, or simply tap the throttle twice.

Today I will ring out the wires to the ECU to ensure proper values and ensure throttle position sensor is at 15 degrees at closed position.

If anyone can do a service bulletin search or provide assistance, I would be truly grateful.

[gordonw]

Don't think procedure DI-117 is the correct one, should be DI-118 for inspecting throttle control motor. P1128 looks like it only has two outcomes of which replacing throttle control motor with magnetic clutch is one solution. The other is to check the throttle valve and make sure theres nothing caught between the valve and the housing. If there is, remove the foreign object and clean the throttle body or if there isn't, replace the throttle body. I would definately check wiring or anything else as the throttle body is a bit expensive. Sorry, can't help you with wiring though, good luck.

[Maingear]

With nothing better to do, I replaced the Throttle position sensor and the accelerator sensor. I rang out all wires to the ECU before changing components. Oscilloscope and voltage readings are fine until trouble code is logged.

Removed the throttle body, cleaned, inspected - looks / operates like new.

Total spent on parts so far - $620

Not having any car payments and the pleasure from working on the car myself - Priceless

Could it be an obstructed catalytic converter? The car does have 140K Miles on it.

[Maingear]

Forgot to update...

Cleaned dust from ECU with alcohol (allowed 2 days to dry) and all symptoms went away. Reinstalled original components. Car has been running fine for over a year.