Chevy Lost the VOLTS? (HV Battery DISABLED - P1FFF P0AA6)

hi everyone welcome back to Pine Hollow auto diagnostics yep we're sitting inside the XL7 it's raining outside they're called in here on this 2012 Chevy Volt and customer complaint is check engine light is on and there's a warning on the dash that says the high voltage EV battery is not charging so I did a full code scan and we have two codes in the HP cm2 hybrid powertrain control module says p0aa6 hybrid EV battery voltage system isolation lost and system isolation coolant level sensor fault hybrid EV battery charging system disabled so if this code sets then this code sets because it disables the charging of the battery it is the system isolation is lost so first time for me working on one of these Chevy volts 90 000 miles on it let's do some research on these trouble codes see if there's any interesting information Where Do We Begin our diagnosis all right so there's a TSB on this exact issue vehicle will not charge and hybrid loss of isolation with DTC p0a6 and or P1 ffff those are the two codes that we have this one and this one so potential causes to consider when evaluating the vehicle are one a loss of hybrid EV battery pack coolant external or internal to the hybrid EV battery pack or a loss of high voltage isolation within the battery cells or battery sections themselves hmm recommendations ISO locate the isolation test resistance that is located in the HP cm2 data list under data display and note the current value on the repair order also note the isolation resistance from the freeze frame records um here okay perfect so we have to start by not clearing codes but actually going to freeze frame and seeing what this resistance was olation resistance when the code set inspect the height EV battery pack coolant level by doing both of the following you know the coolant level is low in the under hood Reservoir remove the drain plug for the battery to see if the water coolant drains out indicating coolant leak inside the battery pack interesting and this battery pack lives I don't know if I get my internet back under the car if you look at component views oh let's see control valve coolant pump let's go back a couple there here it's under the car so it's in the transmission tunnel I guess here's all the electronics and it has coolant going through it and it's a GM so it possibly could go wrong there's the layout and then the actual code description here the p0886 hybrid EV battery voltage system isolation lost it's equipped with a monitor and the purpose is to test resistance between the high voltage positive and negative direct current DC bus and Chassis ground it has a special feature that tests with an AC signal on the high voltage system monitors it's amplitude reduced amplitude return signal indicates a loss of resistance to chassis ground isolation monitor method is sometimes referred to as an active isolation monitor okay it runs on all the contactors are open that's key so conditions for setting the DTC the battery energy control module is detected active isolation resistance less than 325 kilo ohms interesting so let's go to the scanner go to the live data well we can look at the freeze frame for this code right here and this is the beauty of Bluetooth scanners the cars over there in the garage keys on and we can look at anything we want to right here so on page four of freeze frames as isolation test resistance 225 kilo ohms and the minimum is 325 kilo ohms okay what's the you know if the test just ran again is this when you say DTC display this thing says passed and failed and it's currently locked out so it's not charging this battery so my question is currently did this test pass so data stream I'll just pick one of these battery pack isolation test status so and there's a test resistance so right now it says isolation test status passed six um isolation test resistance 3000 kilo ohms so basically I'm assuming it's good open circuit now the owner says when the this code sets it's been on for about three weeks um it obviously has been wet outside and the car's been sitting for a few months before the code sets so is there possibility there's some condensation uh inside the battery pack said the coolant level was fine um and right now the test you know it passed the most recent test he's been driving it for a while so I mean it's the car is drivable it's just not charging the uh high voltage battery in the TSB it says you know check the coolant level he said he checked that is fine removing the drain plug for the battery or that involves raising the car up um if any moisture is found during the drain plug inspection contact the GM technical assistance center wow very important I hit the cool level in the reservoirs at a proper level and there's no coolant or water drain from the battery from the drain plug inspection for 2011 2014 program the hpcm to and the becm with the latest calibration if the DT sets again review Freeze Frame information again and follow the SI Diagnostics so my question is if we don't find any problems of this with this car right now do we do this programming or do we just let the owner drive it until the next time this happens and then we'll say Hey you know bring it to the shop because we need to lift the car up we do this inspection uh with the you know for water inside the battery and then if it if all those things pass we can reprogram the module I think that's the best plan of attack so I'm just going to reset the codes for now and give it back to the customer and basically say if it happens again you got to bring it over for uh further Diagnostics so that's it for now there's a follow-up we'll uh we'll do that later so I tried clearing the trouble codes and this code is not being cleared it says current system isolation coolant level sensor fault hybrid EV battery charging system disabled the car still is still fussing so my question is if we go back and cp1f one ffe there it is P1 FFF cool level sensor sensor tested coolant surge tank yups two-stage switch which changes state when the level of the coolant pack and searching reaches approximately 100 milliliters changes when the battery cool low on certain gets low low state is the lower resistance state of the sensor normal low State high resistance so it's either on or off basically the hybrid EV powertrain control module uses the coil sensor determine the control charging operation okay uh once DTC is set the DTC will not run again until a clear code command is sent conditions for setting the DTC so if this code is set this code will be set type adtc yep only clear the clear code command will not clear go to history with ignition Cycles we'll only clear the clear code command I tried it it did not clear yep I verified that the hybrid EV battery cooling system is full in order to clear the P1 ffff the k114b hybrid EV powertrain control module 2 may have to be programmed even though the module contains a current calibration level that's nuts so you have to program the module that's crazy okay so basically we have to do this again and we we have to actually do the programming to clear this code you can't just clear and send the customer on his way that sucks for the customer but that's what we have to do uh before programming anything I want to try this in the special functions reset functions hybrid EV battery contactor open reasons reset and right here contact open reasons we have hybrid EV battery system pre-charge time too long yes and shutdown mode yes so let's reset those refer to the service manual for instructions reset device limit exceeded high voltage interlock circuit contactor not open oh okay there's no way around it you got to pay GM money to program this thing that's too funny so I actually have techline connect installed on this little laptop and uh all you need is the Bosch Master Tech 2 pass through all right here we go pass through is connected and we're gonna jump right into sps2 um [Music] so we have to program this k114b and the k16 modules so we're going to reprogram next there's k16 [Music] and the key was it the one one four [Music] k114b [Music] battery energy control module there it is k114b hybrid powertrain control module 2. next [Music] um coolant surge tank update includes new anti-tamper bracket on cap let's see here's our surge tank so this is for the engine this is for the hybrid system this is the anti-tamper thing so it is updated obviously the coolant level is perfect there and there so we're going to select with next yes next current calibration is 2129 in calibration so I'm going to control print screen this and then say next [Music] start programming because it says even if it's the most current calibration still do it writing the ECU take a little while [Music] all right vehicle processing data and let's finish that and then the TSB also said reprogram the k16 module um and that's battery energy control module see if we can do that one at the same time so we don't have the warning anymore okay next see new software addresses the isolation issue found on the Gen 1. so let's just go ahead and do that all right so programming is complete we've got no warnings can we shift it into reverse yes we're shift in the drive yes we'll let go see check engine light is still on so let's get the regular scanner out scanner for codes one more time see if see if it's happy or it's a good you know or if it's not happy all right looks like good news everything's green on the scanner everything's green and the dashboard's a very green car so I'm Shifting the reverse car goes back Tifton Ford car goes forward so I'll give it back to the owner and tell them drive it and if this problem reoccurs then we'll actually you know check the battery for moisture or whatever but how about that to clear the code on this car you have to reprogram the module that's ridiculous uh so it's going to cost don't worry a programming fee just to clear these trouble codes but that's the way GM operates and hopefully the car will be fixed at least for a while thanks a lot for watching we'll see you next time so the owner said when this problem was present you couldn't charge it from the wall so this is a special charger that came with the car yeah is that okay and then it plugs in right here and if the green light is on that means green is good so it's charging and hopefully it'll stay happy foreign

Channel: Pine Hollow Auto Diagnostics

Views: 66,827

Keywords: GM, EV, Hybrid, module, battery, HV, voltage, isolation, coolant, programming

Id: 2Deq-ukpttM

Length: 19min 50sec (1190 seconds)

Published: Wed Jan 25 2023