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Was in stop in go traffic the car completely shut off, reduced engine power, service active handling, service traction system, battery saver active. Clicked the start button and it would not start no crank at all. Window power radio hazards worked fine.
Sat there for 5 minutes or so.
I open the door when someone was going to help me push it off the road and got back in to give it another start up try and it fired up briefly getting me off the road.
Towed it to the closest dealer since that was the free option and hours later went back with a different battery they said it fired up.
Drove it halfway home before it died again service active handling, reduce engine power.
I had been using my seat warmer at the time thinking it was pulling too many amps causing issues with the alternator output if it is failing.
I have a mechman alternator i plan on installing hoping it resolves the issue however i doubt it will. DIC was showing 14v when this all happened.
Codes:
EBCM C0242
EFCM P166A
ECM P0601
Any thoughts to point in the right direction let me know. I will double check all the BCM passenger footwell connections.
Was advised to check the sensor on the transmission (A6) not exactly sure where it is located or how easily it is to access without a lift.
Plan on adding seafoam for the gas tank thinking possible clogged fuel line. I do not have the ability to test the fuel pressure.
Would i have any codes set if this is a failing cam or crank sensor?
Failing ECU?
Both batteries were fully charged 12v with a multi meter when i tested them after the failures.
Thanks for any pointers.
Last edited by Got uid0; Jan 20, 2019 at 12:43 AM.
Seems like ECM or your wiring kit would be a good place to start searching for issues.
C0242 is an out of range code for a signal received from the ECM for traction control.
P166A code is for exhaust flaps.
P0601 is just the generic reduced engine power code.
Fully Charged Battery should be more like 13.8. 12v and a load will drop battery voltage to around 10-11v. Fuel pressure gauge is inexpensive. Very well could be cam or crank sensor. Corrosion in battery cable or something loose between alt. and battery?
Alternator did not provide the fix as expected.
Car continues to fail after reaching operating temp. It throws the codes dies and then does not want to crank until it cools down a bit or i clear the dtc.
Throttle body plates have some brown tarnish on them.
Last edited by Got uid0; Jan 20, 2019 at 12:26 AM.
If these are with the motor running, you have major problems with the re-outs. Hence running, evap purge should be closed, and evap solinoid should be showing a percentage of how much it venting. Also, should be showing a percentage of the TB opened, as well as the accelerator pedal as well. Hell motor load should be around 6% at idle as well.
So start the motor, then pulling the DTC to see what is not showing up on the GM lan bus, and then the read-outs of the motor running.
Lastly, double check the connection bolt of the alternator cable to starter solenoid, since it may a header heat problem with the connection loose and alternator voltage not making it to the battery as the connection point heats up/battery not being charged from the alternator.
I will do another screen capture after i put the fuse box back together i was double checking all the connections again even tho that was done long before this issue popped up.
I may have posted some captures when it was off either way it was done while in park. New alternator installed 170amp mechman as the stock was not keeping up when at idle stereo going etc. Engine cut off happens with original and new alternator.
if you can tell me where to go in tech2 and what to capture i appreciate helping rule out or identify where to look. Fearing a corrupt ECU
Pretty sure you have a bad negative ground cable that goes from your battery to the chassis ground. If not that then you need to replace the positive cable that goes to your starter and fuse box. These cables can look good, but inside they get corroded and the car will die. It's most likely not the ECU.
I will do another screen capture after i put the fuse box back together i was double checking all the connections again even tho that was done long before this issue popped up.
I may have posted some captures when it was off either way it was done while in park. New alternator installed 170amp mechman as the stock was not keeping up when at idle stereo going etc. Engine cut off happens with original and new alternator.
if you can tell me where to go in tech2 and what to capture i appreciate helping rule out or identify where to look. Fearing a corrupt ECU
Also noticed a bit of oil in the intake may need a catch can with the big cam.
I have checked it and it seems ok. Battery volt meter terminal test shows 12.6v DIC shows anywhere 14.6 - 15
Today it died after letting it idle getting oil temp up to about 140. Previously i would sit and give it some gas every once in a while and would cut off about 180 oil temp time frame.
As soon as it triggers the DTC it will not start or attempt crank. It has to sit about 10 mins to allow me enough time to get it in and out of the garage. If i clear the code immediately after it sets it will crank and then trigger the code and shut off.
What could be getting too hot that could cause? I do smell something hot smelling but unsure if it is due to recent install of a heat shield on the tunnel plate. I crawled under and looked for burned marks on it but found none so i am unsure if it is the material inside the lg heatshield that is stinking and unrelated to this failure.
EBCM module was replaced a while back. I know the trigger is happening after bad signal reading to ebcm setting c0242.
Not sure if it is normal but while running some of the data scans i clicked the mild to wild remote switch to open the flaps which caused the scanner to temporarily loose communication on the data capture.
I appreciate everyone's input
Last edited by Got uid0; Jan 22, 2019 at 11:43 PM.
Personally I'm very averse to using nonfactory wiring or alarm kits because I've seen multiple issues similar to this caused by them even though everything appears completely fine.
That said I'd pay close attention to the cable integrity of everything near your headers.
What type of burning smell? Is the smell present when driving without issues? Maybe check some reviews for the product you bought and see if there's a smell after install. The smell makes me think a ground cable near your header is getting burned up.
Are you able to establish full communication/functionality with the ECU when it will crank but not start?
How are you being sure the no-start trigger is when the ECBM code is being set? (Didn't check your freeze frame time caps sorry)
Personally I'm very averse to using nonfactory wiring or alarm kits because I've seen multiple issues similar to this caused by them even though everything appears completely fine.
That said I'd pay close attention to the cable integrity of everything near your headers.
What type of burning smell? Is the smell present when driving without issues? Maybe check some reviews for the product you bought and see if there's a smell after install. The smell makes me think a ground cable near your header is getting burned up.
Are you able to establish full communication/functionality with the ECU when it will crank but not start?
How are you being sure the no-start trigger is when the ECBM code is being set? (Didn't check your freeze frame time caps sorry)
Better than looking good i used a multi meter and confirmed the ground is good from battery post to battery ground right front ground, alternator house and left front ground.
Are you familiar with what a big 3 wiring upgrade is? It's purpose is to help fix bad factory wiring and grounding issues. Everything factory is still in place it just gets an added 4 gauge cable to improve alternator and battery and ground strap.
The smell is hard to describe other than it doesn't smell right and did not smell like that prior to the heat shield and tunnel plate. Slight clutch like smell slight brake fluid smell. I have not found anything melted. I believe it is strong near the brake booster.
Last edited by Got uid0; Jan 29, 2019 at 11:41 PM.
Better than looking good i used a multi meter and confirmed the ground is good from battery post to battery ground right front ground, alternator house and left front ground.
Are you familiar with what a big 3 wiring upgrade is? It's purpose is to help fix bad factory wiring and grounding issues. Everything factory is still in place it just gets an added 4 gauge cable to improve alternator and battery and ground strap.
The smell is hard to describe other than it doesn't smell right and did not smell like that prior to the heat shield and tunnel plate. Slight clutch like smell slight brake fluid smell. I have not found anything melted. I believe it is strong near the brake booster. brae fluid is green in the reservoir.
I am aware of what they are, it's a logical upgrade, but in practice I feel like I see them cause more problems than solve (although I usually see them hand in hand with questionable electrical mods in the first place).
From my experience I'd say you're dealing with some type of communication loss from your ECU and in the LS's I've seen that's typically caused by either a bad harness, bad ECU itself or a bad ground/wire. Your symptoms kind of sound like intermittent ckp sensor failure as well but those will almost always throw a code when it won't start, and the no crank till clear points towards an electrical/ecm issue. Are any of the modules unable to communicate when it won't start? Also are you mechanically or electronically clearing the codes? (Pulling battery or clearing scanner).
Code gets cleared with a scan tool. This is how i can see the ebcm and efcm code. C0242 P0601 P166A all triggered while sitting in park or driving after car warms up. Seems like it happens a lot quicker than the first 2 events while actually being out on the road about 5 miles reaching operating temp.
Either the ECM/PCM is truly bad as the code says p0601 and cannot process the signal correctly triggering the other two codes or vise versa.
The cool down time is what has me puzzled as i would believe that should point me in the direction of detecting the source. Which could be a bad computer chip or solder point perhaps.
One of my tests was clearing the code right after it triggered using a vxdiag nano with tech2win software. Pushed the button it cranked and immediately died. Let it sit and then i can start it up.
I bit the bullet and working on an ECU swap as rare as this condition is on a 2012 hopefully it is not a costly mistake.
Last edited by Got uid0; Jan 28, 2019 at 07:22 PM.
From the codes I see I'm pretty confident the ecm is the culprit.
Watch the tracking.... It's on the way!
Stay TUNED!
Chuck CoW
I'd be pretty confident it's going to be a harness/wire or internal ECM issue. Interested to hear how it goes and hoping this solves it. If you don't mind me asking, have you seen similar issues with those codes specifically or are you basing it more on the data for no-crank/start and code trigger conditions?
I'd be pretty confident it's going to be a harness/wire or internal ECM issue. Interested to hear how it goes and hoping this solves it. If you don't mind me asking, have you seen similar issues with those codes specifically or are you basing it more on the data for no-crank/start and code trigger conditions?
It's pretty simple.... P0601 in an INTERNAL PCM MEMORY Checksum failure.
The ECM has the ability to test it's memory by writing to it, and then reading it back to see if it gets the same result....
If it writes a ZERO.... and reads it back as a ONE.... That's a checksum/memory failure and most of the time it's DEATH for the ecm.
The controller will usually not RUN or start if it's a confirmed failure, because the results of unstable memory could cause disaster for the
engine and/or the driver.
If you get the code once.... it might run again.... If internal diagnostics detect it again.... the throttle closes and the engine goes into REP
or Reduced Engine Power.
It's one code you can save yourself trying to diagnose most of the time..... The ecm is DEAD and there ain't no fixin it.....
Just call Chuck CoW and he's usually got a whole bunch of them and I can usually get you back in the saddle pretty quickly....
Even if you have mods and tuning.....
And heck.... Getting a good ecm back with my CoW BOOSTER! sure makes most of the sadness disappear!
Diagnose Car shut down
