Alert 972

[Curt]

Has anyone run into "Vehicle Alert #972: DMC FW: Accelerator Error fault"?

I got this half a dozen times yesterday. Oddly enough, right after leaving the local Service Center for work on my trunk latch.

Each time, I lost power and regen, and found the car coasting. Had to pull over, switch off and on again, then was able to proceed for a while. I checked the connector on the pedal module, and it seems to be secure.

I limped back to the Service Center, avoiding all highways (one more occurrence during the return trip), where they had set up an after-hours loaner pickup.

Hoping for good news on Monday, but the Service guy who took my call just gave the now-standard reply that it "might be the PEM".

 

[wiztecy]

The accelerator pedal has multiple pick-ups to relay the position of the pedal position to the computer. My best guess would be one of these pick-ups has failed / contacts are dirty and triggered a fault hence why the system is shutting down. Doesn't sound like a PEM error really unless its a really bad translation of an error message.

 

[Curt]

The accelerator pedal has multiple pick-ups to relay the position of the pedal position to the computer. My best guess would be one of these pick-ups has failed / contacts are dirty and triggered a fault hence why the system is shutting down. Doesn't sound like a PEM error really unless its a really bad translation of an error message.

Thanks, @wiztecy - that is my take on it, as well. I figured the readings between the potentiometers weren't in agreement. Checked the connection to the pedal module, since that was something I could do on the spot, and it seemed that a bad connection might cause this problem. Still had one more occurrence after that, so I'm thinking some component has likely failed.

 

[PV-EV]

FWIW:

972 DMC "DMC FW: Accelerator Ratio Error fault" Red Fault 1 Vehicle Wiring Harness - Open/Short

972 DMC "DMC FW: Accelerator Ratio Error fault" Red Fault 2 Accelerator Pedal Failure

972 DMC "DMC FW: Accelerator Ratio Error fault". Red Fault 3 PEM - Internal Failure

 

[wiztecy]

Thanks PV-EV, interesting to see that there is one PEM related alert that could exist in that message. Curious how to distinguish via the VDS debug / message console which of the three was indeed the root cause. I'd also recommend Curt to dump his log files and begin analyzing the standard Unix "messages" file to see if any other details happened to be logged.

 

[Curt]

FWIW:

972 DMC "DMC FW: Accelerator Ratio Error fault" Red Fault 1 Vehicle Wiring Harness - Open/Short

972 DMC "DMC FW: Accelerator Ratio Error fault" Red Fault 2 Accelerator Pedal Failure

972 DMC "DMC FW: Accelerator Ratio Error fault". Red Fault 3 PEM - Internal Failure

Thanks, @PV-EV and @wiztecy! This might be useful.

The Service Center had my Roadster for four days, and couldn't reproduce the problem. I had them replace the Pedal Module, as it seems to be the most likely culprit.

I could use some help here. I haven't dug into the logs this deeply. How do I determine whether these were Fault 1, 2, or 3 using VMSParser (or another tool)? I don't even see how to view the generic error here.

I've unpacked the log tar file. Nothing in the messages file except that they dumped the logs to a Sandisk Cruzer Glide USB device.

 

[PV-EV]

Curious how to distinguish via the VDS debug / message console which of the three was indeed the root cause.

I too would like to know the answer to that question. There must be some data in the logs to indicate the fault "rank" (how my list describes it) but I have yet to figure it out. Some codes have as many as 6 different ranks.

 

[wiztecy]

Curt, do you have a picture of the fault which appeared on your screen? That's the best way I found to identify the rank, there's a hex code that's unique with each message which I believe is a one to one key to the rank. Other than that, try to find the unix system log file that also is archived with the logfile dump.

 

[Curt]

Curt, do you have a picture of the fault which appeared on your screen? That's the best way I found to identify the rank, there's a hex code that's unique with each message which I believe is a one to one key to the rank. Other than that, try to find the unix system log file that also is archived with the logfile dump.

Sadly, no. I was too busy trying to avoid being hit by others as I recovered from the fault. I wish I'd seen this about 4 hours ago. I could have taken the time to get a picture in one case.

At any rate, it seems the issue may be heat-related. It was hot last weekend, then cooler all week, and hot again today. I had six more occurrences today and have dropped my Roadster off at the Service Center once again.

I do have logs from earlier this week, if anyone has experience with deciphering them. I haven't found anything yet looking through them on a UNIX system.

 

[PV-EV]

That's the best way I found to identify the rank, there's a hex code that's unique with each message which I believe is a one to one key to the rank.

I've looked at the hex "data" that appears on the VDS along with errors and have not seen a direct correlation to a rank. Given, I don't have a lot of examples to look at. Not saying you're wrong, I just haven't seen it. I have meant to try to figure it out but haven't devoted the time. That might be the start of a new thread...

 

[slcasner]

Is the hex number that appears on the VDS reflected in the log record for the fault?

 

[PV-EV]

Is the hex number that appears on the VDS reflected in the log record for the fault?

It seems like it must be but to date I have not tried to correlate VDS errors and their hex data to the log of the same event. maybe others have??

 

[wiztecy]

Hi Curt, I talked with a good friend of mine who has deep roots with the Roadster and asked about the #972 fault. This is what he had to basically say.

The circuit that measures the (dual) potentiate is indeed located in the PEM. He noted that the actual pedal assembly rarely faults. However he also said that the wiring has been at the root of the issue, in particular ground. He commented that the 2.x / newer cars had the signals passing though an intermediate board in the center console, and the connectors are a bit wonky it seems.

The potentiometers are down in the pedal assembly, the rest of the components are in the PEM.

 

[Curt]

The Bad News...
The Service Center has had my Roadster now for over 3 weeks (aside from the two days between replacing the Pedal and faults occurring again), and they have never reproduced the problem. They have now decided to replace the entire PEM.

The Good News...
Since I had the "3.0" Battery Upgrade done at the end of February, the PEM replacement is covered under the 36 Month Battery and PEM Warranty.

 

[slcasner]

The 3.0 battery warranty covers the PEM also? That's (good) news to me.

 

[DaveD]

The 3.0 battery warranty covers the PEM also? That's (good) news to me.

Wow, same here! I'm gonna double-check that with my friendly Tesla Assistant Service Manager.

 

[supersnoop]

The 3.0 battery warranty covers the PEM also? That's (good) news to me.

They modify the PEM as part of the 3.0 upgrade, so it comes with a warranty.

 

[gregd]

They modify the PEM as part of the 3.0 upgrade, so it comes with a warranty.

I thought the replacement parts warranty was only 1 year. You get 3 years with the 3.0 upgrade? This is good news! I mean, it's a rather expensive way to get an extended warranty on the most likely and costly items to fail. The only significant item remaining is the motor, but they aren't known to have such troubles as the PEM and Battery. But we do get a tangible warranty!

 

[Curt]

I thought the replacement parts warranty was only 1 year. You get 3 years with the 3.0 upgrade? This is good news! I mean, it's a rather expensive way to get an extended warranty on the most likely and costly items to fail. The only significant item remaining is the motor, but they aren't known to have such troubles as the PEM and Battery. But we do get a tangible warranty!

I wouldn't go so far as to say "tangible". I've been asking for a copy of the warranty since March, and haven't seen anything so far. I was unaware that the PEM was covered until they told me yesterday.

 

[slcasner]

I thought I had heard that the warranty only covered the part of the PEM that was changed in the upgrade.

I did not get any warranty statement in writing, either. I did get a verbal statement of 3 years or 36K miles.