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Check engine light on

25K views 44 replies 11 participants last post by  LauriJT 
#1 · (Edited)
My check engine lamp stays on. Pushed OnStar button, they said it was a propulsion error POA9E.
Anyone know if that is serious. Charges ok and I get around 44 mile to a charge. I have 1183 EV miles and a 100 CS miles. Have only used 3 gal gas so far.
BTW my Volt runs perfectly with no indication of any problem.
Les

Del 1/6/11 have not bought gas in 2011 yet. VIN 567.
 
#6 ·
P0A9E isnt as serious as it is annoying
Basically it means one of the temperature sensors in the battery pack is being detected as "shorted out"
If your Check Engine Lamp continues to be "ON" for the nest 3 or more "trips" then it's probably not intermittent and a you should take it to your dealer.
It wont really cause anything dramatic in terms of fail-safes so your Volt will probably continue to operate as normal, but ...

Depending on how the diagnosis goes they will likely just swap out the entire battery! (the current strategy for ANY faults internal to the battery box) So don't bring it in until you know you can leave it for a couple days (they should hook you up with a rental though)
Keep us informed!
WOT
 
#7 ·
My light went on two weeks ago and stayed on for a week. I did not contact OnStar or the dealer. I read in the manual it could be related to an improperly closed gas cap, so I opened and closed the gas cap but that did not immediately solve the engine light problem. I’m not sure what the cause was but I suspect it was caused by unplugging the car, powering it on until the charge on the battery dropped one mile and plugging it back in. Currently the check engine light only lights during power up then goes out, normal operation. I’m not going to put my theory to the test and just continue to drive it as I have.

300+ miles, and still over three quarter tank full of gas.

Volt #671
NPNS!
 
#8 ·
Thanks WOT,
That is good to know, so I can plan ahead. I'm certainly disappointed that my perfect so far Volt has developed a problem. Having to change out the battery seems like major surgery that should be put off as long as possible. I'll sure have to think about that.
Les
VIN 567 1225 EV 105 gas
 
#9 ·
I'm certainly disappointed that my perfect so far Volt has developed a problem. Having to change out the battery seems like major surgery that should be put off as long as possible.
Naw, take it in. We're all beta testers. GM's going to learn more from us then they could with a decade of in-house testing. The best thing you can do for GM is take your car in for repair, so they can see what the failure is. Debugging and fixing failures now will enable GM to produce hundreds of thousands of EREV cars in the future with few warranty issues.

Don't be bashful! GM *NEEDS* to see each and every problem in our initial Volts. It's a totally new drive train, and they'll be lots. The only way GM can fix them and stay alive is for us early adopters to help them identify issues.
 
#11 ·
The reality is the battery swaps out from under the car with nary an indication.So assuming that i what they decide to so, it' pretty uninstrusive.
My intention was to inform you that your DTC is indicating a fault that shouldnt result in a seriou isue that would "strand" you somewhere on the road, or result in any serious collateral damage to any of the Volt's systems.
But you should get it into your dealer as soon as convenient.
HTH
WOT
 
#12 ·
More CEL data. Last Tuesday, I went to the dealer with the CEL read by onstar of POA9E (battery temperature sensor shorted). The dealer plugged in to read it and the lamp went out, and they not able to read error. They said to drive it, and if it came back, I should return. The CEL showed up again on the way home and stayed on all week. I returned today, they checked it out, said they located the defective modules and have them on order. I can come back Wednesday, at which time it will take 3 to 4 hours to install if I wished to wait.
Les
 
#13 ·
Did they say whether they were swapping out the entire battery pack? or just replacing the Battery Interface Control Module (BICM) itself? The reason I ask is this points to the root cause of this fault.(i.e. temperature sensor itself, vs. input monitoring equipment/controller)
Let us know what happens Wednesday!
WOT
 
#14 ·
WOT & Rusty,
All is well. They did swap out the battery and updated the software. I got to participate in the software updates. It was interesting to see that huge battery there and the special fixture and jack to install it. From pictures you don't realize how really big it is. No more CEL for now.
 
#16 ·
My check engine light (CEL) just turned on today. OnStar ran a diagnositcs report and said that there is a problem with the propulsion system and that I should take it in for servicing within one day. So tomorrow I will be at my dealer with my Volt that has been running perfectly up until now. Actually it still is running fine with the CEL on.
 
#17 · (Edited)
So they didn't give you an actual DTC then? The Onstar folks are pretty much being trained to say "there's a problem with your propulsion system" whenever a fault is detected. (and recommend a dealer visit)
With certain DTCs that have set on the early Volts it might only be as a "reprogramming" to alleviate the issue.
So knowing the actual DTCs present would help us, to help you, as far previous experience documented here in the forums.
Or you could just take it to your dealer and get them to look after it ASAP
WOT
 
#19 ·
After 4 hours at the Chevy dealer today they could not figure out why the Check Engine Light (CEL) Is ON. It was frustrating to me because the "certified" Volt service technician told me that all he could do is extract the data from the car onto a PC, and upload it GM and then wait. He said that he then must wait for a "Volt Engineer" to come to the dealership to determine what the problem is. The service manager told me that there are only 2 regional Volt engineers covering Southern California so he didn't know when he would get there. The service writer wanted me to leave the car there indefinitely until they could figure it out but I opted to take the car home after the technician extracted the data from the vehicle onto his PC. The service manager will call me when the Volt Engineer can be there.

The technician told me that when talking on the phone with GM they thought the fault had something to do with the heating system. When I got into the car to leave the heat was set to 88 degrees and I noticed that while the vehicle was stationary in the service bay it used up 10 percent of the battery charge (via iPhone app while bored in the waiting area). Here are the DTCs that they gave me so if anyone knows what they are please let me know. By the way, when I left the dealer the CEL was OFF.

P1AFO
P1AFZ
P1EZZ
P0AC4
U0121
U0254
 
#20 · (Edited)
@Frankman
Hmmm well I think that all your Z's are probably 2s (the DTC are in hexideximal code so "F" is the highest letter used)
and I dont really like what I see if they are in fact "2"s (Loss Of Isolation DTCs?)

But I will be AFK over the next day or so but will look into these DTCs once I return but in the meantime if you wouldnt mind double-checking your documentation and confirm that:
P1AFZ isnt actually P1AF2
and
P1EZZ isnt actually P1E22

Thanks
WOT
 
#21 ·
You may be correct on the "Z" being "2" instead. The codes were hand written on a piece of paper that the dealer gave me, and it wasn't very neat.

When I was at the dealer they did say something about loss of isolation but I didn't understand what it meant. Later (after my post), the Service Mgr. called me and said that he talked with an Volt Engineer and they needed to get some sort of high voltage tool to test the isolation problem, and they didn't have the tool at the dealership. He said that the tool emits high voltage to do the test. But then later, after he talked with someone else he called me and now they believe the problem is a heating control module that needs replacing. Because by this time it was 7 PM in Detroit, the next conversations will take place Monday morning. If they all concur that the problem is the heating control module, the part will be ordered and installed later next week.

I drove the car yesterday after my service visit and the CEL has not turned back on and everything seems fine. I told the Service Manager about this and he said that the technician did not clear the CEL. So why would it be off now? Thanks.
 
#25 · (Edited)
No problem, please let us know how it all plays out.
A megger is a special tool??!? I had to have a megger to work on my '77 Subaru! Gave up on it when the pneumatic analog computer got too messed up.
LOL Really?
What the @#$% did Subi use a megger for? Spark plug wires?
AFAIK they havnt really become a required automotive tool since the hybrid era commenced.
WOT
 
#28 ·
Got my Volt back today from the dealer and everything seems good. The service invoice lists updated software for BCM, ECM, PIM, HPCM2, OBCM, HVAC, APM, NAV, USB and Radio as outlined in TSB PIP4875. I don't know what most of the updates actually changed, but it did reset some of my settings, including the radio presets (Favs).
 
#29 ·
I noticed a difference in the fuel mile range estimate after since the car has been serviced, even though the amount of fuel in the tank has not changed. The iPhone app has reported 6 gallons of fuel in the tank for the past month or so. It also showed 6 gallons or 66% when I received the car back from servicing. However, the estimated range for the fuel has changed, and it just changed again after refreshing the iPhone app even though it still shows 6 gallons remaining. It just changed from 193 miles to 201 miles. Prior to bringing the car to the dealer for servicing showed 228 miles. Does anyone know how the estimated range is calculated for fuel (gas) and why it would change even though no fuel is being used?
 
#34 ·
The Check Engine Light (CEL) could be caused by many different problems according to my dealer's service dept. When my Volt's CEL turned on, the OnStar people ran diagnostics and said it was a vehicle propulsion problem. It turned out to actually be a faulty heater control module that was replaced and it fixed the problem. Others have reported that the CEL required the battery pack to be replaced.
 
#36 · (Edited)
I had my Volt at the dealer yesterday to fix a problem with my front running lights not working which they found, as explained to me, as a loose connector with bent pins. They had to take off the front fascia to get to the connectors. So I have working running lights and the parking assist sensors are working now which I didn't notice wasn't working but now I get the beeping sounds. Anyways... This morning I started up the car and the check engine light was on. I contacted OnStar and the code they gave was P1ECE which I haven't found searching the forums here. The rep explained it as basically the battery charger noticed voltage out of range. After hearing that I remembered that last night I found the MyVolt website saying the car was plugged in but not charging. Went to the car and found the dashboard indicator off. I unplugged and replugged and it started charging and had a full charge this morning. The car is charging now but the MIL has been on all day. So does P1ECE mean anything critical? Can I give it a few days before going to the dealer?

Update-- The OnStar rep also mentioned that I wouldn't charge at the higher level or some such and that the gas engine would run more often.

Thanks
Gene
#954
 
#37 · (Edited)
Gene
P1ECE indicates a problem was noted with the on-board charger output.
It's posible have been related to the work they had completed as the charger is also in behind the front bumper fascia.

When this DTC is failed "hard" (existing problem i currently present) charging operations will cease, but you should still be able to drive the car. However since you CAN charge your Volt, I supect the fault was temporary and would also expect your check engine light will actually go out after a couple of drive cycles. (it has to see a couple of successful charge cycles)
You may not even see it again.

But if the CEL persists or charging issues continue you should return to you dealer at your earliest convenience to have this addressed in case it's more serious
HTH
WOT

PS> Were you charging on 120 or 240 Volts?
 
#40 ·
The check engine light did indeed go out this morning. Or actually last night when I was playing with remote start after the car had been plugged in for a few hours. So in my case it took 3 or 4 days for the system to clear the error I'm guessing due to no further issues after the initial event.
 
#41 ·
Good news. Hopefully permanent but...
Yea, putting out the MIL /CEL for an intermittent Type A or B DTC is sort of a moving target. Variables exist that affect being able to "run" any particular diagnostic routine, so your fault had to meet that criteria and verify a "pass" on 3 consecutive trip cycles before the lamp is extinguished. If it comes back ON then you are much more certain that the fault has a level of frequency that should make it "diagnosable". Otherwise it's difficult to identify fault in component or circuitry that are at the time- performing correctly. Hopefully you won't see it again.
WOT
 
#42 ·
Sorry for digging out a very old topic. I had this same p0A9E error that temp sensor 1 is out. Now since time has past and chevy is no longer in europe, ampera is dead. And to top that nobody here has a permit to touch a hybrid car. Or actually has, but volvo dealer can only service renault and volvo, hyundai only hyundai and so on. No ampera service here. So we are now in finland and we now have to drive ampera to nearest service (120km away). Aaaand because the lack of chevy and ampera dead, dealer allready warned that this might well take weeks. Many many weeks. Lucky me i have three cars so no worry as i only hope i get my ampera back this year time. My biggest fear now is that there is always a danger present that i get to pay all. Even though i first checked that battery waranty is still on.

Actually asked the cost of 5 year/120000km service. They said it would be about 940€ with battery coolant change.... Well if this goes to warranty, there is no longer need to pay for coolant change. That actually is the only good thing i can think of now about this.

But this all got me thinking. Ampera is a very good and nice ride, but because the lack of support now it is pretty hard to own here. I think next one will be hyundai for me even though i would like to have chevy bolt. Cant see that happen if chevy does not come back here.
 
#43 ·
Well this fault seems to be temperature sensitive.it was -10 celsius at night before fault started. Now it has been several days warmer and so check engine light is no more present. Faults are still stored but i really hope opel/chevy does not clear them automatically so that there still is a mark when service looks at it.
 
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