2016 Denali 6.2L Clearing Permanent DTC's

[GHuggins]

Are you sure there isn't another connector somewhere unplugged? P0118 is coolant temp or sensor - should be on side of driver's head (bad to get left unplugged with engine work or go bad in general) / P0300 is misfire / Others are the oil and a comm code.

[svl208]

P0118 was unplugged. Plug it in and that DTC went permanent. I believe the ECT is on top of the water pump housing on this engine?

I think there's a Misfire? I'm gonna load the PID's and check that after work today. I also borrowed a buddies scanner if I need it?

What about a crank relearn that could be causing the miss fire?

Thanks.

[GHuggins]

If it's a dead miss then that's one thing. If it's a roaming all cylinders cam miss then that's something that has to be fixed in the calibration.

[svl208]

Holy schnikes!

I found the problem! At least I hope I did?

I set up PID's in the scanner to watch for misfires. #7 right off the bat had waaaaay more. Swapped plugs, Swapped wires, Swapped coils and the misfire stayed on #7.

Pulled the valve cover. I didn't see anything broken or bent. Had my son turn the engine over and the rocker and everything was moving as it should.

Then my son seen it! #7 cylinder exhaust valve spring broken at the bottom coil! That has to be the #7 misfire and that has to be what is putting it into reduced power.

I been days on this truck for my nephew. Supposedly all this was replaced by someone else with all comp cams stuff. Springs, seats, and retainers, and everything when they did his cam. Truthfully it all fits like crap. The top retainers are all off center to the top of the spring. Rockers look forced. That's why I do my own work. Even if I don't know what I'm doin? Cuz at least I'm the one that screws up my own sh$%. Lol.

Once I get new springs, retainers, seats and stuff I'll verify repair and post it.

Thanks for the input! It helped keeping my mind goin and not giving up.

Thanks!

[GHuggins]

It's good you caught it when you did. When the LT's were first on the scene shops were installing the wrong springs and causing coil bind. This coil bind was wiping out the valve guides and making motors burn 2quarts every 600 or so miles... Sounds like a cluster. I absolutely hate going in behind others that don't know what they're doing. Always interesting with what you find. I'm willing to bet that it has to pass the P0300 before it will run the other test and once that is fixed you might be good to go.

[TheMechanic]

Conditions For Running The DTC
P0117
The ignition is ON.
OR

The engine is running.
This DTC runs continuously within the enabling conditions.
P0118
The ignition is ON.
OR

The engine is running for greater than 10 s.
OR

The engine run time is less than 10 s when IAT Sensor 1 is warmer than -7?C (19?F).
This DTC runs continuously within the enabling conditions.
P0119
DTC P0117 or P0118 is not set.
The ignition is ON.
This DTC runs continuously within the enabling conditions.
Continuous DTC is basic circuit tests. Checking for opens, shorts to ground, shorts to power or skewed data.

Conditions For Running The DTC
The system voltage is greater than 11 V.
DTC P06DA, P06DB or P06DC runs continuously when the above conditions are met.
Conditions For Setting The DTC
The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 0.25 s.

Action Taken When The DTC Sets
DTC P06DA, P06DB and P06DC are Type B DTCs.
ECM commands the engine oil pressure control solenoid valve OFF.
ECM commands Reduced Engine Power.
Conditions For Clearing The MIL/DTC
DTC P06DA, P06DB and P06DC are Type B DTC.

[TheMechanic]

Enable criteria for the P06DD