'95 SC Riv - lots of errors

I have a '95 supercharged Riv that has a number of error codes popping up. The first sign of trouble was probably a couple of years ago or so when I noticed that the Traction Off light would come on every once in a while. Then a couple of months ago it morphed into the Service Engine Soon light along with diagnostic codes P0321 (Ignition System 18X Interrupts) and P0361 (Ignition System Elec Spark Timing EST Not Toggling). This came and went for a while, but for the most part the car ran fine. Sometimes the engine would be a little erratic, but it was fairly temporary.
In the last few days though I am getting a host of indications and error codes. They are as follows:

Dash Indicators:

Service Engine Soon
Traction Off
Check Oil Level
Low Coolant Level
ABS

The Low Coolant Level and Check Oil Level indicators come and go together. I found that they will go on and off in response to the gas pedal so long as I was going over 50 or so. Giving it gas would make these two indicators go away while letting up on the gas would make them come back on (at least I think it was that way - it could have been just the opposite).

While the car is in this failure mode the Electronic Climate Control and the Cruise Control do not even power up. I could stop the car, turn it off, and restart it and sometimes that would fix it for a while, but it would always come back at some point. Also in this failure mode the car would oftentimes run very bad. When starting from a stop the engine would rev, but the car would only slowly start to move similar to how it would be if the transmission were slipping really bad (my tranny was rebuilt less than 2 years ago, so I think it is fine (besides - it only does that when I have these crazy intermittent indicators).

I had the codes read again today at the auto parts store and here is what popped up:

Current Codes:

P0571 ABS Traction Control PWM Signal Problem
P0640 Quad Driver Module QDM 1 Fault
P0670 Quad Driver Module QDM 4 Fault


History Codes:

P0321 Ignition System Problem 18X Interrupts Lost Signal
P0361 Ignition System Problem Elec Spark Timing EST Not Toggling
P0406 Linear EGR Pintle Position Error
P0571 ABS Traction Control PWM Signal Problem
P0640 Quad Driver Module QDM 1 Fault
P0650 Quad Driver Module QDM 2 Fault
P0670 Quad Driver Module QDM 4 Fault
P0705 PRNDL Switch Failure

My first instincts are the computer, but I really do not know. Anyone have this trouble before?
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http://ucfpics.com/95Riv.htm

When I had codes P0321 and P0361, the computer was the culprit. I'm leaning that way in this case because of all the faults that are showing up. I got a used computer at a junkyard for $50...a cheap and easy fix for several problems.

I will give that a try. Where is the computer located on the Riv? Is there anything you have to do to initialize it or anything like that?

It's behind the passenger side kick panel - easy to get to, though it'll break your back! The computer is very general and was used in several cars, which is good in that you should be able to find one relatively easily (I used www.car-part.com). Just take the PROM chip out of your current one and put it in the new one (very easy to do - just open up the access panel).

Unplug the battery when swapping the two computers to reduce the chance of frying the new one.

Replacing the computer fixed several problems with my old '95. Obviously the SES light no longer came on, but even better was the fact that the tranny no longer clunked hard when the torque converter clutch engaged - I had always assumed that was a mechanical problem!

It sounds like a very similar computer was used in the Riv's as the Bonne's. 94/95 were horrible years for Bonne.

I may add checking the grounds and battery cables, any number of issues can happen with loose or bad/corroded connections.

BillBoost37 wrote:

It sounds like a very similar computer was used in the Riv's as the Bonne's. 94/95 were horrible years for Bonne.

I may add checking the grounds and battery cables, any number of issues can happen with loose or bad/corroded connections.

Yeah, I'll bet they used the same computer. I was in contact with a guy who had a Park Ave who had a similar problem as me (got those same two codes). He eventually replaced his computer to fix the problem, and that's what inspired me to do it. The computer I got was actually for a Lumina minivan, so I think it was probably used in a wide variety of cars.

Good point on checking grounds and cables. I always forget about that!

Thanks for the help. I called the local parts house and they have this for $112.00:

A1 Cardone 773247 Engine Control Module

Do you know if this is the right one (a net search shows plenty of images) or is the ECM not the same as the PCM?

You may want to check your local junkyards. By me they are about $20 used. Most buddies with 94/95's get two and keep one in the trunk as a spare.

I would also vote for used.

Thanks again. I need to make sure I am getting the right part though. Can you look at my post above and tell me if the ECM is the same as the PCM or are they two different computers?

Engine Control Module and Powertrain Control Module generally refer to the same computer. The terms PCM and ECM come up often and are usually interchangable.

I am pretty sure their listing for ECM is the right part.

Powertrain Control Module is how the term evolved when they added Transmissions to the computer function. In the early days the ECM only controlled the Engine. Later it controlled transmission too, so they changed it to Powertrain.

I think your Trac/ABS light will be a wheel speed sensor gone bad, it's quite frequent. It means you need to replace a wheel bearing. Most likely front, but I don't know how to tell you which one.

Good luck
-Derek

That sounds like the right part. The number I had on the ECM (or PCM or whatever) was 16183247 (maybe it's good that I don't delete old emails!).

Oh, and I wouldn't bother with the Trac/ABS lights until the computer stuff is taken care of. One of the problems I faced with the bad computer was a 'Traction Off' light that would show up at random times.

OK - thanks. I will give that a shot.

The Riv is finally back up and running. I tried two different refurbished ECM's from the auto parts store to no avail. Same error codes.
I was going out of town for the holidays, so I left the car with the dealer. They fixed it. Turned out to be a bad ignition switch. Not cheap though. $230.00 for the switch. $552.00 overall.