PEM No data fault ID:56

[KeithBoxer]

Hi I have the following debug message ID:56 PEM No Data Fault. Which I guess could be that the VMS has lost contact with the PEM? I have tried removing and reconnecting the connector on the RHS of the PEM. Is there anything else one can try to resolve this, before calling Tesla Service?

 

[PV-EV]

I think losing 12v to the PEM or VMS would cause this. If not the connector on the PEM then it might be the APS itself. Any work been done on the car lately? Accidents? Custom work? The APS is buried in the ESS. Verify that VMS works by trying trunk release. Check VMS fuse #21. Try inhibiting and then enabling APS in the service menu.

 

[PV-EV]

There is also a fuse for the TCM (transmission control module) in a small fuse box on the right side of the trunk by the PEM. Some vehicles may have a single in line fuse.

 

[KeithBoxer]

I think losing 12v to the PEM or VMS would cause this. If not the connector on the PEM then it might be the APS itself. Any work been done on the car lately? Accidents? Custom work? The APS is buried in the ESS. Verify that VMS works by trying trunk release. Check VMS fuse #21. Try inhibiting and then enabling APS in the service menu.

Thanks I have checked the Small fuse by the side of the PEM, it looks ok. The car has been sat in the garage since we went into lockdown in March. The only problem I noticed was that the ESS coolant was low and that has been topped up. I did notice that the pump was running quite frequently.
I have tried to find fuse #21 but on my fuse box the VMS is not listed. See image. Could it be somewhere else..?

 

[PV-EV]

#21 is correct. Trunk release and door locks (among other things) are controlled by VMS so it sounds like that is working. If the APS overheated on low ESS coolant it could shut down and cause this error, as reported by others but you should have seen more errors and warnings. Have you pulled logs and examined the error history? Did you try the inhibit/uninhibit APS from the service menu? When you say the fuse by the PEM looked good, did you test it? The TCM ECU controls the shifter. Depending on your comfort level with working on your car, and how accessible and trustworthy the local service center, i would try pulling the orange main service disconnect and re-installing. Instructions can be found by searching this forum. Have you checked the auxiliary battery? The fuse for that is under the front hood on the left side as you face the car. Your problem sounds related to the 12v system to me. Loss of or low 12v can cause the control systems to brown out. 12v is supplied by both the APS and the auxiliary battery. Good luck and report back on your findings or the findings of the service center so we can all learn from this.

 

[KeithBoxer]

Thanks Jack. I believe you are correct about the 12v system. I spoke with Peter Gruber who suggested I test the voltage of the input connector into the PEM. I’m not sure if it should be a constant but it varies. Some of the time it is at 13.5v eg when the pump motor is running, but when the pump is off the voltage drops to around 0.5v . Is that normal. Should I check the auxiliary battery voltage?

 

[X.l.r.8]

I’ve found with peter, he usually steers you on a path of logic and the best result is to report back your findings and proceed to the next step. Testing lots of things out of sequence sometimes muddies the waters and I am guilty of this in blind panic mode, a $1000 repair could easily have cost $200 had I stayed the course.

 

[PV-EV]

You should check the aux battery. Especially if it hasn’t been replaced in the last couple years. It might not be the cause of this problem but if it is not in good shape it will be an upcoming problem. I honestly don’t know if the APS is always on. I didn’t think so. No one else seems to be chiming in with helpful ideas so hopefully Peter can help you with additional troubleshooting. Let us know what you find!

 

[KeithBoxer]

I’ve found with peter, he usually steers you on a path of logic and the best result is to report back your findings and proceed to the next step. Testing lots of things out of sequence sometimes muddies the waters and I am guilty of this in blind panic mode, a $1000 repair could easily have cost $200 had I stayed the course.

Thanks, I've sent to the Logs to Peter and waiting a response, I will post here when I have a solution to the issue.

 

[KeithBoxer]

You should check the aux battery. Especially if it hasn’t been replaced in the last couple years. It might not be the cause of this problem but if it is not in good shape it will be an upcoming problem. I honestly don’t know if the APS is always on. I didn’t think so. No one else seems to be chiming in with helpful ideas so hopefully Peter can help you with additional troubleshooting. Let us know what you find!

Thanks Jack. I tested the aux battery voltage at the fuse under the hood and it read over 13v so seems the battery is OK. I asked Peter Gruber about the 12v power supply to the PEM and he didn't consider it strange that it was sometimes at 13v and other timed almost zero. So maybe the APS only comes on when needed. If I find anything more useful I'll be happy to share.But thanks for all your helpful suggestions this far.

 

[PV-EV]

Ok, but normally you would pull the fuse and check the battery side. Max should be about 12.7. When the car is ON the APS charges the battery through the switchpack with about 13.6v. Something like that. Either way I don’t really think this was your trouble.

 

[KeithBoxer]

yes I think the 12v battery seems OK and power is coming from etc APS to charge the aux battery. My conclusion so far is the there is probably an issue of communication between the VMS and the DMC or the PEM, but I cannot trace its cause. I have sent the data logs to Peter Gruber as he requested and am awaiting his response.

 

[KeithBoxer]

Ok, but normally you would pull the fuse and check the battery side. Max should be about 12.7. When the car is ON the APS charges the battery through the switchpack with about 13.6v. Something like that. Either way I don’t really think this was your trouble.

Hi I saw your message about not mixing thread topics, so will try and do that going forwards

 

[KeithBoxer]

Hi I saw your message about not mixing thread topics, so will try and do that going forwards

So just to repeat from the other thread...
I tested the voltage either side Of the fuse on one side it was 13.8v on the other 13.5v but I was surprised that there is power on both sides when the APS is inhibited?

 

[PV-EV]

Confirm a couple items. Previously you said the car would not move, even in tow mode.
Will it charge?
The rear trunk lid will open with the button on the dash?
The glove box will open with the button on the dash?
When you pulled the fuse for the TCM by the PEM did you check for 12v in the fuse holder?
What is your SOC?

 

[KeithBoxer]

Confirm a couple items. Previously you said the car would not move, even in tow mode.
Will it charge? NO, the white light does not come on when trying to charge.

The rear trunk lid will open with the button on the dash? YES
The glove box will open with the button on the dash?YES

When you pulled the fuse for the TCM by the PEM did you check for 12v in the fuse holder? YES. When the car is awake it is around 13.6V. when the car is asleep it goes don to nearly zero.

What is your SOC?

Is around 67% see photo.

Thanks for helping! I'm home all weekend is there anything else I should try? I have now got a cable that can connect an OVMS, that also connects to a PC I assume. If that helps at all?

 

[KeithBoxer]

Hi again, I provided answers to your recent questions in the thread above.
One thing I have noticed is that whenever I test 12v systems I get a reading of around 13.6V at most locations , apart from the cable in the passenger footwell that is used to connect the OVMS. There I get only 11.7 v. Is that strange, or is it normal that there would be some fluctuations?

 

[PV-EV]

The car has three sources of 12v besides the aux battery. The APS has a main 12v output, a separate APS 12v output that goes to the PEM and there is a small 12v output from the ESS that powers the standby 12v. From my armchair location and limited qualifications it seems those are all working just fine. The TCM communicates with the PEM and the PEM controls the charge port lights so it looks to me like the trouble is internal to the PEM. If it was mine I would take the PEM out and investigate further but you should wait for a recommendation from a professional like Gruber. The Service Center will no doubt say “new PEM”. Hopefully I am wrong.

 

[gregd]

The +12 at the diagnostic connector (where the OVMS attaches) varies depending on whether the car is awake or asleep. Awake I see 13v.; asleep it's more like 11.4 (per an uncalibrated OVMS module).

 

[KeithBoxer]

Yes I get the same, at the diagnostic connector (where the OVMS attaches) I have the same results 13.6v awake and 11.7V asleep.