GM Volt Forum banner

1 - 20 of 87 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
I have a 2012 volt with 19,000 miles, so far no problems whatsoever, except for a CEL that has come on a few occasions, which clears out quickly. However last week it didn't clear out, so I called OnStar and they said it was codes P1E00 and P0A0C - Vehicle Integration Control. I took it to the dealer but when the volt technician tested the car he said the CEL was off and he said everything was fine.
Does anybody know what this code means and should I worry about it?
Thanks.
 

·
Registered
Joined
·
2,336 Posts
P1E00: Hybrid Powertrain Control Module 2 Requested MIL Illumination
P0A0C: High-Voltage System Interlock Circuit Low Voltage
 

·
Registered
Joined
·
4,728 Posts
The high voltage interlock circuit is essentially a safety feature that will shut down the high voltage battery contactors when improper access to high voltage components is detected without properly disabling of the high voltage system.
P0A0C (interlock circuit low voltage) is commonly set if the manual service disconnect (MSD) in the center console was removed or reinstalled improperly or if the underhood access shroud over the power inverter module was removed. If these haven't been tampered with then there could be an intermittent connection issue somewhere within the interlock circuit at various other components and connections. Sorry to say that unless the technician inadvertently repaired the intermittent connection during his/her "checks" then the condition is very likely to return.
WopOnTour
 

·
Registered
Joined
·
69 Posts
Hello WopOnTour, you seem to be really smart on these cars as I have seen several posts involving troubleshooting from many users, I have a real challenge for ya I think,
Earlier this year I bought a 2012 volt that I purchased for a restoration project (car was wrecked, poor thing should have been totaled really) I have spent probably $2-3,000+ dollars in parts and I have the car completely together minus some small body work and headlights. Im working out the little kinks now dealing with with some smaller issues with the car, namely addressing the DTC's on it that resulted from the crash. To save a huge hassle and cost in constantly towing it back and forth to the dealer perhaps a million times I decided it would be a good long term investment to go ahead and purchase the full GM-Volt R/CAR service manual set and an annual subscription to GDS2.

I have cleared all the DTC's involving the inflatable restraint system, as I was told by one of the volt techs at the local dealership that the car will disable the high voltage system after an accident. since rebuilding the car I've also cleared the "secured high voltage DTC's in the hybrid powertrain control module 2 section like the service manual states. The service manuals are a bit vague however about the exact procedure of reinstating the high voltage system after an accident. Based on some research I've done online It mentions to have "a scan tool" clear the "Crash event detected condition" but I assumed that GDS2 would do that for me since the ACdelco team has also told me that GDS2 is largely required for this specific car and the tech2 tool is being phased out of use in the newer GM vehicles. I guess my question is is the tech2 scan tool or a subscription to tech2win specifically required to clear the crash event detected condition or am I somehow missing something within GDS2 to do this? I have gone through all the modules in GDS2 and can't seem to find anything else to restore the high voltage system.

I also have this particular code P0A0C and the service manual instructs me to perform voltage and continuity checks on the MSD and x2 connector on the hybrid powertrain control module 2 which I'm fine with that, but doesnt tell me exactly where this connector or module is located, or which pins are "pins 28 and 30" etc. I also get a P0D17 battery charging system high voltage interlock circuit low voltage, which I'm pretty sure thats the connector shorting out that tells the system that high voltage connector is connected, I think I pretty much know whats causing that though..

I guess a bit of a point in the right direction to start with is what I am looking for I suppose. The service manuals don't seem to mention anything about the hybrid inverter cover missing as part of that system that causes P0A0C which it is. I figured the plastic cover over the inverter was largely cosmetic though, and thus havent bothered with it, since you told me that was important though, seems self explanatory on what I need to do there.

I greatly appreciate your input, and admire your knowledge on this remarkable car.
 

·
Registered
Joined
·
4,728 Posts
It's all done with the MDI and GDS2. The Tech2 will not function on the Volt.
The 2 documents you require are:
HIGH VOLTAGE SYSTEM INSPECTION- GM DOCUMENT ID:2551868
AND
CLEARE SECURED HIGH VOLTAGE SYSTEM DTCS = GM DOCUMENT ID 2560217

On that DTC with the car OFF and 12V battery disconnected, remove the MSD and inspect / confirm the small HVIC/HVIL terminals are not bent. Also, the installation of the MSD is a 2-stage process using a double detented mechanical lock so you must seat it once, then push the button on the front side to clear the detent and then seat it a 2nd time. THEN clear the secured (hidden) DTCs followed by a global DTC check and clear.

HPCM2 X2 is not references in the P0A0C DTC chart , Did you mean X1?
The HPCM2 is under the passenger front seat
Use CONTROL MODULE REFERENCES Document ID: 2635370 to locate modules and connector pinouts

Are you using the GM web version of SI or some web based illegal copy?

HTH
WOT
 

·
Registered
Joined
·
69 Posts
Hi WOT, I'm using a genuine OEM MDI tool and a panasonic toughbook set that I purchased used for $2,095 from a dealership closeout reseller. The subscription GDS2 I am using is an annual subscription and I paid another $607 dollars for it including tax. acdelco said I could request a refund prorated the difference if I didn't use it the full year, I was thinking I may need it at most a month or two but who knows, the subscription prices are cheaper if you buy the bigger packages, averages out to $1.70 per day if you buy the annual package, so I went with that. Everything I'm using is "supposedly" authentic. I tried to shy away from the cheap chinese MDI's you find on the internet because I was told from an acdelco tech and a bosch tech that the chinese versions supposedly don't properly give you access to all of the programming functions, and with a car as sophisticated as the volt, I didn't want to skate on something that I would most definitely end up needing later with my luck.

If there is illegal based copies of GDS2 out there I'd like to see how they pull it off. GDS2 from what I can tell is web-based and runs off java only. I'll have to admit I would have been tempted to look into that option with the prices they charge, but I suppose that's just the high price you pay for technology, or so they say.

Shortly after I made this post I found where the module is located in the service manual set, its in volume 3, page 11-420, location: under the passenger seat just like you said. Just to be certain is this also referred to as the K114B module correct? Yes I was referring to the x1 connector, there is also an x1 connector at the junction block in front of the main battery under the car of course, service manual states to perform the checks at the module, funny I keep telling myself read the books maybe you'll find out - lol

Everything appears to be electrically and mechanically sound on the car, the MSD appears to be in good shape, I havent noticed anything unplugged elsewhere in the car. I haven't tried to perform continuity checks on the MSD itself yet but somehow I strongly doubt the MSD itself is defective, service manual states procedure to perform checks on it and to replace it if it is, so I assume anything is possible.

I've also noticed the two stage connector like you said, it would only plug in so far and then you have to push in that little "tab" on the front of it to push it on down further kind of like you said. That seems to be ok, I've again cleared the secured high voltage DTC's on it several times but I'm not sure if I followed that up with a standard global DTC clear, I think I'll give it a shot again and let you know how it works out. If not, my next step is to perform the continuity checks on the K114 like the manual states.

Just curious where your getting these document reference numbers, I'm sure it's with an acdelco's SMI subscription correct? I don't have a subscription to that, for me it made better sense in the long term to go ahead and buy the paperback service manual set so that I could have access to the information whenever I needed it. Downside I'm sure is it would probably take a lot longer to find what you need using the paper copies, probably just do a search and bam there it is online.. I'm sure I'm missing out on the bulletins and such, hopefully I'm not missing out on much there..
 

·
Registered
Joined
·
69 Posts

·
Registered
Joined
·
4,728 Posts
You need to carefully follow the procedure in the "Clearing Secured DTCs" document ID I previously posted
The secured DTCs need to cleared from both HPCM2 (x2)AND HPCM1 using the following sequence EXACTLY:

The Clear Secured High Voltage DTCs procedure requires scan tool interaction with two different control modules in sequence and can be completed using the following steps:

 1. Install EL-49642 SPS programming support tool. (Midtronics or other low-ripple 12V charger)

 2. Vehicle in Service Mode. With a scan tool, Clear All DTCs.
Note: A command reject may appear on the scan tool after the first Clear Secured High Voltage DTCs request. If this occurs, ignore this command reject and continue to the next step.

 3. With a scan tool, select Hybrid/EV Powertrain Control Module 2 Control Functions list. Select Clear Secured High Voltage DTCs and follow the on-screen instructions.

 4. With a scan tool, select Hybrid/EV Powertrain Control Module Control Functions list. Select Clear Secured High Voltage DTCs. Select Continue button.

 5. With a scan tool, select Hybrid/EV Powertrain Control Module 2 Control Functions list. Select Clear Secured High Voltage DTCs and follow the on-screen instructions.

 6. With a scan tool, Clear All DTCs.

 7. Vehicle OFF. 30 seconds


HTH
WOT
 

·
Registered
Joined
·
69 Posts
Hello WOT,

Back on my weekend project with this car, after several attempts following the procedure you have outlined above and by the service manual (which of course tells me the same exact thing) still no luck in restoring the high voltage to the system of this car. My next course of action is to completely disable the high voltage contactors to the car and begin continuity checks directly on the HCPM2 pinouts as the service manual directs.

Just to make absolutely, positively, 110% certain I have done my full due diligence within GDS2, I am going to detail specific step by step exactly what I did as outlined:

1. Install EL-49642 SPS programming support tool. (Midtronics or other low-ripple 12V charger)
I installed the GM MDI tool to the service diagnostic port under the drivers seat and the USB to the laptop (panasonic toughbook)

2. Vehicle in Service Mode. With a scan tool, Clear All DTCs.
Note: A command reject may appear on the scan tool after the first Clear Secured High Voltage DTCs request. If this occurs, ignore this command reject and continue to the next step.

I loaded GDS2 from the acdelco home page, from the home screen I selected diagnotics, vehicle VIN shows up in the next screen. I then put the car in service mode (acc mode) by pressing and holding the power button for a few seconds, car powers up in service mode, selected my car in GDS2, clicked enter. From the main screen I get 4 options, module diagnostics, vehicle diagnostics, system diagnostics, and session manager, I select vehicle diagnostics, then select vehicle dtc information, car displays DTC info with the following dtc's :p1E00 Hybrid Powertrain Control Module 2 Requested MIL Illumination P0D17 Battery Charging System High Voltage Interlock Circuit Low Voltage P257F Engine Hood Switch Circuit High Voltage P0A0C High Voltage System Interlock Circuit 1 Low Voltage B3101 Keyless Entry Data Link Circuit B3205 Driver Window Motor Calibration Not Learned. (I am proceeding under the assumption that the body control dtc's and hood switch dtc is unrelated). From here I select clear dtc's, select add all, hit ok. It says do you want to clear all emissions related dtc's? I again hit ok. I then go back to the main vehicle menu.

3. With a scan tool, select Hybrid/EV Powertrain Control Module 2 Control Functions list. Select Clear Secured High Voltage DTCs and follow the on-screen instructions.
From the vehicle menu screen, I select module diagnostics ->select HCPM2 -> select control functions -> select clear secured high voltage dtcs, here is where it gets a bit confusing, there are no on screen instructions, here it just shows a list of parameters, the control module, and their values. All the parameters check out ok but 3 of them do not. The high voltage interlock circuit status shows failed, battery charging system high voltage interlock status also shows failed. One last parameter shows the hood position short to battery. I did have to replace the hood latch, apparently it is related after all? The connector, harness and 3 pins that connect to the hood position sensor latch appear to be ok. The hood dtc shows high voltage when the hood is open, shorted to battery hood dtc appears when it is shut. Those would appear to be normal conditions to be expected with proper operation of the hood latch, so I am again disregarding it for now (unless the hood circuitry should behave differently?) It does give me the option to "reset" so I do that, then back out to the main vehicle menu screen.

 4. With a scan tool, select Hybrid/EV Powertrain Control Module Control Functions list. Select Clear Secured High Voltage DTCs. Select Continue button.
No issues whatsoever with this step. From the vehicle menu screen I select module diagnostics ->HCPM ->control functions -> clear secured high voltage DTC's. screen then says, "refer to service manual for instructions" (which is what we are doing) i hit continue, after a progress bar scrolls across the screen for a few seconds then goes back automatically to the control functions menu.

5. With a scan tool, select Hybrid/EV Powertrain Control Module 2 Control Functions list. Select Clear Secured High Voltage DTCs and follow the on-screen instructions.
I then repeat the procedure as outlined above in step 3

6. With a scan tool, Clear All DTCs.
I go back to the vehicle menu screen -> vehicle dtc information -> select clear dtcs -> select add all ->select ok message again pops up do you want to clear all emission related dtcs? I select ok then back to the vehicle menu screen.

7. Vehicle OFF. 30 seconds

exactly as stated.
 

·
Registered
Joined
·
4,728 Posts
Hello WOT, any ideas?
Was there an airbag deployment? If so, was the Inflatable Restraint Sensing and Diagnostic Module (SDM) been replaced? or is it perhaps still indicating a DTC B0052 (deployment detected- cannot be cleared) ??

I was under the assumption all necessary repairs had already been performed, but it appears maybe not.
You need to follow all instructions as outlined by Document ID 2623301 "Repairs and Inspections Required After a Collision" BEFORE attempting to clear the secured HV DTCs.

Can you do a full vehicle diagnostic pass for ALL DTCs using GDS2 and list ALL the DTCs present in ALL modules?
(If necc you can use the global DTC function that creates a report that you can save as an XML file and post it here)
WOT
 

·
Registered
Joined
·
69 Posts
There definitely was airbag deployment, nearly all airbag deployments but the ones on the passenger side, as well as seat belt retractor and pretensioner deployments. The Inflatable Restraint module has not been replaced. No DTC's whatsoever can be found on the Inflatable Restraint module, no DTC B0052. I have completed all known repairs to the car that can be visually seen.

I found the problem that was causing the DTC P257F (engine hood switch high voltage) turns out the resistor sensor switch that is inside of the hood latch itself is defective. Resistance reading should be about 700 ohms or so, the service manual states that if not in that specified range, to replace the latch sensor, which I dont believe you can actually buy the sensor/resistor without buying the latch also. As a temporary bypass to clear the DTC P257F off of the HPCM2 I have placed two comparable resistors in series with the connector for now. Since I ordered the part all brand new directly from an authorized GM parts retailer, I will have to take it up with them and wait for a replacement.

The service manual reference for "Repairs and Inspections required after a collision" is page 13-118. The document only speaks of repairs to the airbag and restraint systems, which I've addressed. I'm uncertain of where you are referencing these by document ID numbers. I only have an annual subscription to GDS2 and the 4 book service manual set (in paperback)

Still no luck in clearing DTC P0D17 battery charging system high voltage interlock circuit low voltage or P0A0C High Voltage Interlock Circuit 1 Low Voltage

not many DTC's at all, Ill go pull them for you shortly..
 

·
Registered
Joined
·
69 Posts
Here are the current DTC's I have on the vehicle:

Engine control module:
P1E00 Hybrid Powertrain Control Module 2 Requested MIL Illumination

Body control module:
B3006 Hood Ajar Circuit Open
B3101 Keyless Entry Data Link Circuit
B3205 4B Driver Window Motor Calibration Not Learned

Hybrid Powertrain Control Module 2:
P0D17 Battery Charging System High Voltage Interlock Circuit Low Voltage
P0A0C High Voltage System Interlock Circuit 1 Low Voltage

I'm fairly certain the only DTC's that are applicable to the car's high voltage system at this point are the two HPCM2 DTC's, but your insight would be appreciated.
 

·
Registered
Joined
·
4,728 Posts
OK
I didn't realize you still had a HV Interlock Circuit DTC present (and flagged as "current" I presume but the scan parameters listed in the "Circuit/System Verification can verify this)

This is definitely your issue

There are 2 HVIC circuits but the one faulted is the "Charging HVIC" (see schematic)
But you simply need to review then follow the PD017 chart
You'll notice the DTC chart first checks the circuit continuity between HPCM2 pins 65 & 67 and once confirmed "open" head down to the X5 HVIC connector (grey) down at the top RH corner of the battery junction block (the front plate of the battery assem). The X5 connector "guards" the removal of the HV charging cable coming into the battery near the top of the junction block.
BUT
You may want to first inspect the "easy" connections as then carefully disassemble and inspect the small black fuse assembly on the front of the junction block (after verifying that the system is disabled of course as per "High Voltage System Disabling") MAKE SURE YOUR 12V BATTERY IS DISCONECTED AND THE MSD REMOVED!!

I have seen some potential HVIC issues in the "jumper circuits" going through that little fuseblock cover.
(while you are at it check these 2 fuses but they are not part of the HVIC. if there is a blown fuse though the DTC wont appear until you are able to successfully re-initiate the HV system)

I say carefully as there are seals, dam, and "loop though/back" device under that cover that need to be removed in order to expose the fuses. These all need to have their continuity confirmed. It may have "come apart" in the collision.

Good luck
TAKE SOME PICTURES !! ;)
PS> I hope you have a hoist! I certainly wouldn't want to do ANY of this on my back!

WOT
 

·
Registered
Joined
·
4,728 Posts
The main reason I suggest first checking continuity at pins 65 and 67 of the HPCM2 is simply to verify THEN go to the fuse cover is because the X4 and X5 HVIC connectors can be a bit tricky to remove and install as they have a both employ a small primary lock that needs to be slid back before disconnecting, and they are WAAAYYY up there. So I use a Snap-On cotter key tool (basically an 1ft long pick) to release these. Then you can push on the tab to remove.

BUT re-installation of the X4/X5 connector is even more tricky as there is a secondary "catch" designed into the connector interface that at first appears to block/interfere with reinstallation. So it just needs to be installed at a bit of an angle (facing upward slightly) with a little upward pressure applied to engage the slip past the plastic catch before you "tilt' the connector level (maintaining pressure) and then push it straight in to seat. This is such a tricky little maneuver we actually have a mock-up demonstration and practise session in the Volt technician training in order to be able to accomplish this effectively and without damage. (it's a lot easier with a battery on the work bench lol)

So have fun!
WOT


 

·
Registered
Joined
·
69 Posts
Lol well well there you go - look at you with your big fancy snap on tools, hey check out what I'm using - top notch quality from Pittsburgh - can't ever beat that man haha

Serious note though, yeah I used to be really big on snap on and matco tools but when my fellow colleagues would "borrow" something occasionally they would "forget" to put it back - finally started buying Harbor Freight hey suddenly no big deal. You Lose a snapon wrench or socket you just lost 50 bucks, lose a harborfreight wrench you might have lost .99 cents. Their vicegrips still aren't worth crap though lol but they are getting better, I like their air tools pretty good.

A buddy of mine bought a snap on impact cost him like 500 bucks - had it stolen the same week. Another buddy bought a matco air hammer for $150 and what do you know it just disappeared (he was a newbie though with no box to keep it locked up in, was one of the few tools he had felt sorry for em). I got one for $20 at HF - I just keep my nice stuff at the house now, some cheap stuff too.

getting off on a bit of a tangent there.. I checked all the fuses, took out the passenger seat and performed the continuity checks on the pins, you'd never guess what the problem was
 

Attachments

·
Registered
Joined
·
69 Posts
of course ;)

A broken wire - a broken wire deep inside the main harness was causing the P0D17. Major pain in the you know what to find. Had to dissect the plastic and tape wrapping inch by inch to find it to chase it down, almost near the back passenger fenderwell. Odd place to have a break since that wasn't an impact point in the car.

I assume the accident must "pulled" the wire enough from the front of the car to cause it to break further up the line. Found it yesterday morning, (first time I had a chance to work on it in the last 3 weeks actually). I did the continuity checks on pins 65 and 67 and pins 45 and 47, both read as "open" condition in both circuits, service manuals directed me to repair the open condition in both circuit(s).

Since the wire for the charging unit interlock was broken, the shorting pins when plugging it in was rendered worthless. Soldered the wire and it cleared P0D17 and subsequently cleared P0A0C. I like it when I can kill 2 birds with one stone.

FYI to those independent techs and "do it yourselfers" out there, all of the the high voltage connections in this car have a safety design that tells the system when any of the high voltage connections are tampered with, unplugged, or "broken" this is an additional safety feature in each high voltage plugs design that requires you to first unplug a smaller, harmless "low voltage" connection before allowing you to unplug the larger high voltage connection - this disables the high voltage system preventing any unpleasant shocks which could cause unwanted results such as injury or death. When you unplug the smaller connection it causes an "open" in the circuit, thereby telling the system it's unsafe, so it disables the high voltage connector behind it. When it is plugged in it causes the circuit to "close" or "short out" which tells the system that the high voltage connection is properly made so "it's safe now" Good applause to the design team at GM for the additional steps in making high voltage safety a priority.

Sadly though, my victory was quickly rewarded with a nice P0C78 Hybrid/EV Battery System Precharge Time Too Long.
Give that nice little code a look in your SI chart - looks like I'm in for a dandy of a job.

Per page 11-325:
Diagnostic Aids:
Note: If the high voltage contactors opened while under high current load, replace the drive motor battery wire junction block relay. The following conditions could cause the high voltage contactors to open while under high current load:
* A collision resulting in supplemental inflatable restraint (SIR) deployment.
* A loss of power or ground to the hybrid/EV powertrain control module 2 while the vehicle is moving.


In a nutshell, painfully obvious that senario #1 above caused this condition since nearly every single airbag, retractor, and pretentioner in this car was "deployed" all at once - of course the car was most likely also moving when it lost power, so.. there you go.

Man I'm dreading this one. The relay is $600 bucks plus a core charge of $200 minimum. But the cost alone is not as bad as the very real senario of pulling the main battery - I just had this gut feeling that at some point I would have to do that with this car.

This is where I have a major issues with design, there should be no reason to replace a relay due to a high current condition, a fuse or even a breaker maybe, but never a relay. It is also ridiculous to have to replace the seat belts just because of an accident no matter how minor - the "deployment" of the seat belt retractors locks them up to where you can't ever use them again, never an issue before with a standard vehicle unless the straps or belts themselves were damaged which is quite rare.

The seat belt retractors are about $400 bucks each, not including the cost of pretentioners plus the insane cost of replacing all of the airbags. No wonder over 90% of all Volts that were involved in nearly any accident, no matter how minor, are totaled every time. And if the cost of labor doesn't get you the cost of parts most certainly will, I mean, $300-$400 for just one headlight? It's insane. Buyer beware make sure you keep full coverage insurance on any Volt for full replacement cost because if you don't you had better have some good technical skills and a few thousand bucks set aside for parts - pay a little more now or pay a whole lot more later - no pun intended.

Tell me what you think about P0C78 in your little chart there. If you have any idea tell me what other codes I'm expected to get once I've fixed this one - Curious how many more unexpected lil' codes'll pop up next.
 

·
Registered
Joined
·
2,336 Posts
I'm taking it that you are not looking forward to dropping the battery pack?:confused:




To do this correctly, I suppose you would also need the above EL-49976 battery lift the GM service dept uses to perform this repair.

To me a non resetable relay should be called a fuse. Not sure why GM has this assembly on the battery pack that would have to be replaced rather than just reset. It may be worthwhile to just drop the battery pack to have a closer look at it.

At $600 it is still cheaper to just replace the relay than the whole battery pack. Do you see a problem ordering only the relay from GM rather than getting the entire battery pack w/core charge? As you indicated, there may yet be another issue/DTC even after replacing the relay. If you did next higher assy the entire battery you may be preventing other yet to be indicated issues that may appear.

Good luck on your continued troubleshooting. I can only imagine the satisfaction you will have after successfully repairing your project Volt and actually getting it back on the road!;)
 

·
Registered
Joined
·
69 Posts
Hello WOT, somms, Good news and bad news with the volt project. First the good news I pulled the main drive battery replaced the relay junction block and reinstalled back into the car. Cleared the DTC - no more dtcs On the hpcm or hpcm2. Bad news is when I go back and retry the clear secured high voltage dtcs procedure Still no main power. I am clueless. The only idea I have is when I go under the control functions menu and select "check cleared high voltage dtcs" I get quite a few more dtcs, but they appear to be related to just the high voltage contactor's, one would think that clearing them would reset them, but advice would be appreciated. I'm attaching screenshots from within gds2
 
1 - 20 of 87 Posts
Top