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Discussion Starter · #1 ·
Has anyone had these codes?
EML on and checked with code reader.
P1AF2- Drive motor 2 Control Module isolation lost
P0AC4- PCM requested EML illumination
P1E22- -Auxillary transmission pump control module isolation lost.

Clearly a HV system fault. The Vauxhall Dealer diagnosed this as an issue within the Voltec Transmission.
Has anyone seen this before?
I have seen an old post in GM Volt site describing this as a battery heater problem.
 

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I'll begin by saying that nothing in this post is intended to tempt anyone not properly qualified to try repairing or doing anything to any part of the HV system on their car. I'm just reporting the results of a bit of desktop investigation on a quiet New Year's Eve.

I'm afraid that P1AF2 & P1E22 point towards the traction power inverter module (TPIM) that sits under the black cover on top of the gearbox where all the orange cables go

139122


P0AC4 is, as you have suggested, is just the code that sets when one of the other controllers wants to turn on the orange light as confirmed by you saying the EML is on.

The car continually checks that there is a decent level of resistance (isolation) between the HV battery terminals and earth - the car chassis - and if not sets a code depending on where it thinks the fault lies. The way it does this is by measuring the voltage across one of a pair of resistors halfway between where the the positive to negative range should be, multplying it by two and comparing the result with the actual battery voltage. Any loss of isolation will result in a difference between the two voltages. Interestingly, the hybrid powertrain control module 2 (P1AF2) only tests the hybrid battery assembly for high-voltage loss of isolation when the high-voltage contactor relays are open. All the controllers and the monitoring is inside the TPIM and it is not a repairable item. The repair manual instructions are basically re-programme it first and see if the error goes away and if not, replace the TPIM - GM part no 24279726 currently available in the US for $1646.61.

I'll be interested to hear what the experts found and how you got on.

As an aside, inside the TPIM are the individual inverter modules for each motor and these are things of great complexity and genuinely beauty. See this Youtube vid at about 5:35. I'd have one on the mantlepiece.

Brown Amber Electronics Machine Musical instrument accessory


Happy New Year everyone. 馃嵕
 

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Discussion Starter · #3 ·
I'll begin by saying that nothing in this post is intended to tempt anyone not properly qualified to try repairing or doing anything to any part of the HV system on their car. I'm just reporting the results of a bit of desktop investigation on a quiet New Year's Eve.

I'm afraid that P1AF2 & P1E22 point towards the traction power inverter module (TPIM) that sits under the black cover on top of the gearbox where all the orange cables go

View attachment 139122

P0AC4 is, as you have suggested, is just the code that sets when one of the other controllers wants to turn on the orange light as confirmed by you saying the EML is on.

The car continually checks that there is a decent level of resistance (isolation) between the HV battery terminals and earth - the car chassis - and if not sets a code depending on where it thinks the fault lies. The way it does this is by measuring the voltage across one of a pair of resistors halfway between where the the positive to negative range should be, multplying it by two and comparing the result with the actual battery voltage. Any loss of isolation will result in a difference between the two voltages. Interestingly, the hybrid powertrain control module 2 (P1AF2) only tests the hybrid battery assembly for high-voltage loss of isolation when the high-voltage contactor relays are open. All the controllers and the monitoring is inside the TPIM and it is not a repairable item. The repair manual instructions are basically re-programme it first and see if the error goes away and if not, replace the TPIM - GM part no 24279726 currently available in the US for $1646.61.

I'll be interested to hear what the experts found and how you got on.

As an aside, inside the TPIM are the individual inverter modules for each motor and these are things of great complexity and genuinely beauty. See this Youtube vid at about 5:35. I'd have one on the mantlepiece.

View attachment 139121

Happy New Year everyone. 馃嵕
I'll begin by saying that nothing in this post is intended to tempt anyone not properly qualified to try repairing or doing anything to any part of the HV system on their car. I'm just reporting the results of a bit of desktop investigation on a quiet New Year's Eve.

I'm afraid that P1AF2 & P1E22 point towards the traction power inverter module (TPIM) that sits under the black cover on top of the gearbox where all the orange cables go

View attachment 139122

P0AC4 is, as you have suggested, is just the code that sets when one of the other controllers wants to turn on the orange light as confirmed by you saying the EML is on.

The car continually checks that there is a decent level of resistance (isolation) between the HV battery terminals and earth - the car chassis - and if not sets a code depending on where it thinks the fault lies. The way it does this is by measuring the voltage across one of a pair of resistors halfway between where the the positive to negative range should be, multplying it by two and comparing the result with the actual battery voltage. Any loss of isolation will result in a difference between the two voltages. Interestingly, the hybrid powertrain control module 2 (P1AF2) only tests the hybrid battery assembly for high-voltage loss of isolation when the high-voltage contactor relays are open. All the controllers and the monitoring is inside the TPIM and it is not a repairable item. The repair manual instructions are basically re-programme it first and see if the error goes away and if not, replace the TPIM - GM part no 24279726 currently available in the US for $1646.61.

I'll be interested to hear what the experts found and how you got on.

As an aside, inside the TPIM are the individual inverter modules for each motor and these are things of great complexity and genuinely beauty. See this Youtube vid at about 5:35. I'd have one on the mantlepiece.

View attachment 139121

Happy New Year everyone. 馃嵕
Hello
Thanks for your response.
I downloaded the workshop manual,spent several hours browsing through it and came to a similar conclusion.The error codes indicate loss of isolation in all 3 components ( 2 motors and the aux pump) in the voltec transmission at various times. As all 3 components are unlikely to fail at the same time the problem may be in the Inverter module.
The car is with the dealers at the moment for investigation under HV warranty.
What confused me was that the phone call I got from the service reception stating that the problem is in the 'gearbox' and they need to remove it for investigation.
This I knew was incorrect as it is not necessary to remove the 'gearbox' to diagnose this problem.I hope this was a communication issue where reception staff do not understand the way this car works. I am hoping the trained technician will follow the correct procedures to identify the issue without resorting to unnecessary work.

I am a fan of Professor John Kelly who produces excellent u-tube videos relating to electric vehicles.I can recommend these videos to anyone who owns an electric car. I have watched all relating to Chevrolet Volt.

One thing I have not yet worked out is: Can the loss of isolation somewhere else such as a HVcable or within the battery itself trigger these codes? Are there other codes which identify a fault elswhere?
Thanks for your response and will update when I get the problem resolved.
 

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I hope this was a communication issue where reception staff do not understand the way this car works.
Funny you should say that about service reception. My most recent experience at a main Vauxhall dealer with an 'Ampera specialist' on the staff - I won't name them for now as I'm going to give them a second chance - was less than impressive. My request for a transmission fluid change was recorded as 'transmission change'. As I handed over the keys I casually queried why it would be a 5hr job and the mistake was exposed. Did it end there? Nope. On collecting the car, they had managed to change the engine oil - not the transmission fluid. So we are starting again in January. I had in fact only changed the engine oil back in November. I've always promised myself I would do a double oil change in a car one day, so the oil was really really clean - and now I have :LOL: - how did they know??

One thing I have not yet worked out is: Can the loss of isolation somewhere else such as a HVcable or within the battery itself trigger these codes? Are there other codes which identify a fault elswhere?
As it's an electrical test then presumably it could be a fault anywhere in the circuit being tested. The diagnostic procedure in the manual says to run the 'Loss of isolation on the High Voltage Bus' procedure first which is a sequential 16 stage run-through of all the HV connection components. If the fault is still there at stage 15, it's replace the TPIM. You don't want to get to stage 16 !!

I will watch with interest.
 

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My 2013 Volt continues to report codes P1AF0, P1AF2, P1E22, P0AC4 despite a new +12V battery and a complete battery heater/BDU assembly replacement. (Along the way they also replaced HV battery section 3 upon the addition of codes P0AFA, P1E00, P1B10 and the 'Propulsion Power Reduced' error.)
GM is currently recommending replacement of the power inverter assembly... TBD.
Any updates on your vehicle's diagnosis/fix?
 

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Discussion Starter · #6 ·
My 2013 Volt continues to report codes P1AF0, P1AF2, P1E22, P0AC4 despite a new +12V battery and a complete battery heater/BDU assembly replacement. (Along the way they also replaced HV battery section 3 upon the addition of codes P0AFA, P1E00, P1B10 and the 'Propulsion Power Reduced' error.)
GM is currently recommending replacement of the power inverter assembly... TBD.
Any updates on your vehicle's diagnosis/fix?
I assume your current fault codes are P1AF0, P1AF2, P1E22.
The car is going back to the garage this week. The HV technician was not available last month when it went for the service to resolve the issue.
I have extracted the trouble shooting procedure from the manual for this fault and will be handing it over to the garage in case they have not seen this before.
I have attached a marked up extract here which shows that the troubleshooting procedure is fairly straightforward.
It involves measuring the resistance between the HV bus at connection points for all the HV ancilleries ( Including the power inverter) and the vehicle chasis. If the resistance is less than 750 ohms then that is where the problem lies. If all connections are OK then the HV battery is at fault. Hope this helps. I will update when I get a response from the dealer.
 

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Discussion Starter · #7 ·
I assume your current fault codes are P1AF0, P1AF2, P1E22.
The car is going back to the garage this week. The HV technician was not available last month when it went for the service to resolve the issue.
I have extracted the trouble shooting procedure from the manual for this fault and will be handing it over to the garage in case they have not seen this before.
I have attached a marked up extract here which shows that the troubleshooting procedure is fairly straightforward.
It involves measuring the resistance between the HV bus at connection points for all the HV ancilleries ( Including the power inverter) and the vehicle chasis. If the resistance is less than 750 ohms then that is where the problem lies. If all connections are OK then the HV battery is at fault. Hope this helps. I will update when I get a response from the dealer.
A quick update. I had some feedback from the dealer.
They have followed the procedure and It appears that the fault is with the HV battery.
The usual practice was to send the car to Luton factory for fitting a new battery. Apparently they now cannot undertake installation work but can supply the battery. The dealer has no experience in removing or refitting batteries. They are looking for someone with experience to fit a battery.
This is now beginning to worry me. This is very poor support from Vauxhall for the Ampera. I think UK is lagging far behind in training mechanics in electric vehicles. Only 5% of the mechanics in UK have had any traing in servicing electric vehicles. When I bought the car in 2014 I thought that the support for EVs would be much better than it is now. I may go back to a dirty diesel until 2030.

Has anyone had any experience similar to this? What are the pitfalls in someone without appropriate experience installing an HV battery?The warranty has 2 more years to run. However are there any pitfalls to the owner in this case due to poor installation procedures etc?
 

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As an aside, inside the TPIM are the individual inverter modules for each motor and these are things of great complexity and genuinely beauty. See this Youtube vid at about 5:35. I'd have one on the mantlepiece.

View attachment 139121

Happy New Year everyone. 馃嵕
Looks like an IGBT - i've got a burnt out one that exploded but since its filled with a kind of gel has a point-in-time black-smoke-in-gel effect !

Cheers.
 

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Has anyone had any experience similar to this? What are the pitfalls in someone without appropriate experience installing an HV battery?
If the Voltec warranty is still in force for your vehicle, then you should not have to deal with any of this. You may be deprived of the car for several months, but they should surely provide a temporary replacement either free or at a favourable rate.

But I'm very surprised that it is the battery simply because so few have failed. Has Luton confirmed the diagnosis?
 

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Discussion Starter · #10 ·
I think so.
They were discussing the accuracy of the test readings with Vauxhall Luton over a week ago. Today they confirmed that the battery is at fault.
My guess is that the fault is possibly due to the corrosion in the battery heater as some postings here suggest. Vauxhall UK may not be willing to dismantle and repair/replace internal components of the battery due to many reasons. I am glad I requested the coolant change as part of the 5th service otherwise the warranty would be void. I hope they used the correct coolant last time.
 

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I'd assume, most likely wrongly, that if it is a warranty job and Vx don't have skills in Luton they should source the skills elsewhere, from Europe or the States if necessary (or I suppose give you a decent write off value). But there must be someone here that could do it. Just don't steal Bellinger's man next week, as mine is going in :)
 

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Discussion Starter · #12 ·
If the Voltec warranty is still in force for your vehicle, then you should not have to deal with any of this. You may be deprived of the car for several months, but they should surely provide a temporary replacement either free or at a favourable rate.

But I'm very surprised that it is the battery simply because so few have failed. Has Luton confirmed the diagnosis?
An update.
The car was finally delivered with the problem resolved.
As I initially suspected the problem was with the HV battery heater element. The corrosion of the heater element causes the isolation to break down and creates the error code when the isolation voltage exceeds the set limit of 4.5 volts.
The car was sent to PSA HQ at Coventry (Not at Luton anymore) where they have removed the HV battery and replaced the heater element. It looks like the heater element was redesigned at a later date to prevent this corrosion issue.
More details of the procedure can be found at the following location kindley posted by a GM Volt forum member.

 

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Well that's a good result, but was that approx 3 months to repair?

I suppose that will be a problem even with newer vehicles while the engineering workforce at large get up to speed at diagnosing and repair.
 

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Discussion Starter · #14 ·
Well that's a good result, but was that approx 3 months to repair?

I suppose that will be a problem even with newer vehicles while the engineering workforce at large get up to speed at diagnosing and repair.
Car was handed in to the dealer early February. They diagnosed the problem on the same day. It took a while to convince Vauxhall HQ about the problem. Tests had to be repeated etc.

The Car was sent to Vauxhall HQ and they turned it around in around 2 weeks.It took around 7 weeks in total allowing for logistics of transferring the vehicle, ordering parts etc. The pandemic did not help either due to absence of mechanics.
It is not a difficult repair for a vell equipped garage and it can be done in around 8 to 10 hours if parts are available.
I am hoping that more garages will be able to undertake this type of specialist work in the future when battery powered cars become the norm. Currently none of the Vauxhall dealers appear to be able to undertake work on HV batteries.
 

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Thanks for the clarification, I guess that's not so bad given the nature of the problem (i.e. slightly obscure maybe).

Such a shame they didn't ever properly ramp up in the UK. I'd sure they could still have been selling them now.
 
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