Engine/Transmission (1994 - 1998) Driving with dead ecu

[Advantage Take]

1997. 5 12V. ECU with 3 ~50 pin connectors.



First my problem.

1)Air Bag light is on full time.

2)No response from ecu using OBD computer. (I have tried every protocol I'm sure of this one)

3)No cruise control.



Could it be possible for the ECU to die and the engine to keep on running. I have looked at the wiring diagrams and the engine start/run does not seem to depend on the ECU. Has anyone ever heard of this before?

 

[RStankevitz]

i would say it is possible i dont think our 12 valves rely on the computer for anything other then creature comforts?

 

[hsmith]

Does the cruise on light work? Is it charging ok? I am sure you have looked at the vacuum line at the servo under the driver's side battery. As far as the air bag light, the module is a common problem causing the light staying on.

Not sure about the non-communication problem. Mine is a '96 and I have only hooked to it once, to check some new abs software.

 

[CSnyder]

I would almost guarantee your steering wheel clock spring is broken. Check that out because if it is broken it will cause airbag light and no cruise. You might want to make sure you have no horn or cruise lights before taking your steering wheel off. Changing a clock spring is very simple if thats the problem. There will never be any ECU communication on a 12 valve.

 

[tgordon]

I belive all the dash (Speedo, tach) go through the ECU, anything there?

What trans do you have? Will tha T/C lock up?

A hill, or tow vehicle is all one needs to get the engine started.

 

[GAmes]

To my knowledge there is no ECU. There is a powertrain control module (PCM), and the engine will run fine without it.



On edit; I looked up the PCM in my repair manual.



"Although it does not regulate or control the fuel system on the diesel powered engine, it does operate or regulate the:

Speed control system

Certain warning lamps

Transmission overdrive solenoid

Torque converter engagement

Certain transmission shift features

ASD relay

Air conditioning operation

Tachometer

Intake manifild heater.



So if your tach and A/C are working, I second the clock spring theory.

 

[JacobsD]

the best way to tell if your computer is shot is go outside and turn the key to on and see if the wait to start light comes on. If its shot, it will not turn on.

 

[JSTC]

My 96 did the same thing and it was the clockspring. They are over $200 for a 96 & older. 97 or 98 & newer you can get after market & pay $40. 00. I tried thhis on my 96& the air bag light went out but wiring connectors don't match & couldn't get the cruise to work. John

 

[Advantage Take]

Well know i think the computer is still ok. The alternator does work and it charges the batteries, also the wait to start light comes on. It's probably the clockspring, thanks for your help. I'll return when I've fixed the problem.

 

[Advantage Take]

Anybody ever replaced the clockspring? The connectors don't match and now I'm lost at what to do.

 

[GAmes]

Anybody ever replaced the clockspring? The connectors don't match and now I'm lost at what to do.

I don't know, but you will probably get more response if you start another thread. Good luck.

 

[JSTC]

I've replaced my clock spring with the after market one because the one for a 96 cost over $200. The connectors don't match. I'll deal without cc for now. If anyone had luck with getting their cc to work please let me know.