Alert 972

[hcsharp]

It happened again today. Stuck on the side of the road. My wife was right behind me so she gave me a ride to my meeting. The only thing different this time was that I went over a sharp bump from a small pothole at the moment the fault was triggered. When I returned to the car 3 hrs later it started and drove fine. Not a hint of any problems. Drove two short trips this evening, no problems.

It took until February of this year for my Service Center to get parts for a "PEM Correction", then they told me that they were "very confident" it was finally fixed. Of course, there was no way to know until hot weather returned.

@Curt what the heck are parts for a "PEM Correction"? Did they replace your PEM with a reman? My car's behavior is resembling yours very closely. It appears from your lack of additional posts in this thread that it was resolved. Do you know what they did?

 

[X.l.r.8]

Is there not section in the workshop manual that has all the low level connections? I need an hour on a computer to go through it and see if I can find it again.

 

[hcsharp]

Is there not section in the workshop manual that has all the low level connections? I need an hour on a computer to go through it and see if I can find it again.

There must be but I couldn't find it. Since this problem started I've cleaned the PEM connectors twice. Does anyone know which connector the accelerator signal runs through?

 

[PV-EV]

PEM Connectors:
4 pin = fans
6 pin = ESS heater
14 pin = Motor Encoder
23 pin = logic

Accel 5v = logic 6
Accel 1 = logic 14, rheostat wiper
Accel 2 = logic 22, rheostat wiper
Accel grd = logic 21

The repair manual doesn’t seem very detailed as regards the pedal. Just how to remove it. Nothing about connector specifics. I noticed your photos of the PEM side pins (gold plated) looked very good. What about the mating half? Are those also gold plated and as pristine as the males? Are you sure none of them have been pushed back into the connector? Just some thoughts. Besides the connector at the pedal there are splices in the wiring harness but I have never seen those. Really sounding like a mechanical connection issue with the wires and/or connectors.

 

[Curt]

@Curt what the heck are parts for a "PEM Correction"? Did they replace your PEM with a reman? My car's behavior is resembling yours very closely. It appears from your lack of additional posts in this thread that it was resolved. Do you know what they did?

Henry, your car's behavior does sound similar to mine, but I think the exact conditions of mine were more specific...

What I was seeing happened, AFAIK, only on 1.5 Roadsters which had been updated with the 3.0 ESS and associated PEM change. After that, if it was a hot day (over 32C), and the car had been driven for at least 30 miles/40km, then the problem would start to occur, and would continue until the PEM had significantly cooled. It turned out to be a flaw in the (DMC?) board that was part of the PEM change to support the 3.0 ESS. Inside information from the time was that the only Roadsters to display this exact problem were VINs 55 and 209.

 

[backmost]

I have #209 and so far have no issues with driving in the extreme heat.

 

[hcsharp]

Here I am again today stuck on the side of the road. Been waiting an hour and the fault hasn’t cleared. Had my tools so I pulled all the plugs from the PEM, made sure they were clean and plugged everything back in. None of the pins have been pushed up.

I get the feeling I’m barking up the wrong tree and there’s nothing wrong with my PEM connectors. Not sure what to do next.

 

[dhrivnak]

Here I am again today stuck on the side of the road. Been waiting an hour and the fault hasn’t cleared. Had my tools so I pulled all the plugs from the PEM, made sure they were clean and plugged everything back in. None of the pins have been pushed up.

I get the feeling I’m barking up the wrong tree and there’s nothing wrong with my PEM connectors. Not sure what to do next.

Sorry Henry, I am feeling your pain. I had this error once before, way back when I was under warranty. They ended up replacing the rear wiring harness, which was an all day job. NEver had the error since. They first thought it may be the accelerator pedal and that is possible in your case. What I was told is there are two potentiometers on the accelerator pedal. If they readings do not match when compared in the PEM you will get the fault and the car will shut down. It could also be caused by a lose ground.

 

[PV-EV]

So you could check the pots from the wiring harness at the PEM with a good test ohmeter which would test the wiring all the way to the pedal and back but if it goes back to working like yours has then that test might be inconclusive. I think there are actually two splices between the rear of the car and the pedal but I don’t know just where the connectors might be. I have never seen a wiring harness diagram. It is really unfortunate that we cannot get more detailed information when we need it to keep our cars on the road.

 

[X.l.r.8]

 

[X.l.r.8]

 

[X.l.r.8]

 

[X.l.r.8]

 

[X.l.r.8]

 

[X.l.r.8]

 

[X.l.r.8]

 

[X.l.r.8]

Thats all the connections male and females and there locations.

 

[hcsharp]

Thank you! Where did you find all that info?

 

[X.l.r.8]

I gather information!

 

[hcsharp]

I suspect one of those connectors FHC to MHC to RHC is the culprit. Both of the last two times it happened when I went over a serious bump in the road. Today it was a bridge expansion joint. The only possible good news is it's now 7 hrs after the event was triggered and the fault is still active.