21 chevy equinox limp mode help

[Gacerra1]

Last week i was driving my 2021 equinox with 32k doing 70-75 and the stabilitrack lights and traction control came on and engine derate (limp mode) while driving. I got to the side of the road and tried restarting the car, after a few times i got it to turn over and start and limped it back home and tried disconnecting battery terminals to reboot possibly. Didnt work, lights came back on and i was still in limp mode but it was allowing me to go a bit faster so i brought it to chevy dealer nearby hoping whatever issue was still under warranty. Dealer ended up jerking me around for a few days after initially scanning car and telling me it was “most likely” under warranty long story short they didnt get to the car in the original agreed upon time so i was already aggravated. When they finally started diagnosing the car chevy they asked me for an additional 5 hours at $185 an hour which i declined. I Tried picking up the car a few days after initially bringing it in and the car wouldnt start and had go get it towed out Initial codes were p0336, U0422,
U0401.

I eventually got the car out of this chevy because i felt like i was being jerked around, brought the car to a friend of a friend, they replaced the crankshaft positioning sensor, the car starts fine now and drives but its losing power in higher gears and is still throwing codes p0335, p0336 and p228c.

absolutely any help would be amazing please

 

[Big Papi]

The first two are circuit performance codes for the CPS. Check wiring, connectors and if An aftermarket, cough Dorman cough cough, sensor was used replace it with a factory DelCo part. There is an outside chance the tone ring for the CPS may be damaged. A crank, cam correlation test using an oscilloscope will reveal the condition. The last code is for fuel pressure so stick a gauge on it see what you get. Remember DTC's are not parts lists. Good luck.

 

[PoManNox]

Just to add to what @Big Papi suggests, you may need to keep a scanner plugged into the vehicle for when it acts up. Have some data PIDs queued up for fuel pressure, misfires, etc. The fuel pressure code P228C could be the cause or could be a symptom. Junk aftermarket CPS's are definitely suspect.

IMO, It may have been a good idea to agree to a few hours labor for the dealer to do a diag for you, but if they really wanted 5+ hrs at nearly $200/hr? Yeah, I'd tell them to get bent too. IMO, dealers are horrible troubleshooters anyway.

 

[Gacerra1]

oscilloscope

Just to add to what @Big Papi suggests, you may need to keep a scanner plugged into the vehicle for when it acts up. Have some data PIDs queued up for fuel pressure, misfires, etc. The fuel pressure code P228C could be the cause or could be a symptom. Junk aftermarket CPS's are definitely suspect.

IMO, It may have been a good idea to agree to a few hours labor for the dealer to do a diag for you, but if they really wanted 5+ hrs at nearly $200/hr? Yeah, I'd tell them to get bent too. IMO, dealers are horrible troubleshooters anyway.

Local mechanic installed a dealer oe crankshaft positioning sensor today and changed fuel pressure regulator sensor. Car started normal and was test driven, tachometer was lost and chk engine light back after 5 minutes of driving and traction control light and stabilitrak errors. Codes were ran again p0335 and p0336 no fuel regulator.

Tomorrow the mechanic is going to send for another crankshaft positioning sensor to eliminate the new one being faulty as well. I asked about a multimeter being used for all correlating wires they said yes. But who knows im at a loss for words.

I have another connection at a different chevy, it seems the car will be going there next if this mechanic cant figure it out. Just unfortunate i will be going into the pockets so quick on a newer car- Thanks for the replies guys. Really appreciate it!

 

[Gacerra1]

 

[PoManNox]

I would graph the output signals from the cam position sensors with a scan tool or scope first to see if they look normal and are in phase. Known good graphs can be had online. Guessing and winging parts at it does work 50% of the time. I wish I had an answer for you man.

 

[PoManNox]

I saw on another forum where you posted this same thread, all these problems were caused by a weak battery.

 

[Gacerra1]

I saw on another forum where you posted this same thread, all these problems were caused by a weak battery.

Did a battery load test. All good

 

[Gacerra1]

Did a battery load test. All good

Crankshaft sensor changed 2x no good

 

[PoManNox]

Ah! I misread that post. You were describing someone else's battery problem.

So you've replaced the crankshaft AND camshaft position sensors? Are these known good genuine GM parts and not aftermarket or counterfeit?

 

[Gacerra1]

The code was p0335 and p0336 crankshaft positioning sensor was changed 2x with real dealer part, also the fuel regulator changed and that code didnt come back.

 

[Gacerra1]

Car will start after chk engine light is cleared but then die few minutes after goes back into limp mode. If you Try to restart engine, it just clicks 100 times rapidly.

 

[Big Papi]

Car will start after chk engine light is cleared but then die few minutes after goes back into limp mode. If you Try to restart engine, it just clicks 100 times rapidly.

Voltage / current drop. Check your Starter and engine to frame connections. Power and ground.

 

[Gacerra1]

Voltage / current drop. Check your connections. Power and ground.

Yup checking those now

 

[Gacerra1]

Bad ECM was the issue FYI