multiple MAF related codes - troubleshooting tips?

Hi All,
I have a l86 tahoe here, struggling with the multifunciton sensor in the intake pipe. Codes are as follows:

0x7E8: P0097 - Intake Air Temperature Sensor 2 Circuit Low (Permanent)
0x7E8: P00C7 - Intake Air Pressure Measurement System - Multiple Sensor Correlation (SES, Pending, History)
0x7E8: P00F4 - Humidity Sensor Circuit Low (Permanent)
0x7E8: P0113 - Intake Air Temperature Sensor 1 Circuit High (Pending)
0x7E8: P2227 - Barometric Pressure (BARO) Sensor Performance (SES, Pending, Permanent, History)
0x7E8: P2228 - Barometric Pressure (BARO) Sensor Circuit Low Voltage (Pending, Permanent)

Vehicle was driving great - but oil pressure gauge dropped to zero, and dash said shut off engine -- check
Noted that the oil was 1.5 qt low. Topped off and restarted
Gauge still zero - but no noise etc.
Checked codes and the above were active.

After several hours of chasing 5v reference signals around etc, looking through diagrams and troubleshooting. -- every wire harness is intact, not wear in the harnesses etc. THe oil pressure gauge came back, and the vehicle still runs great, although, when it throws the codes above (intermittent) -- it will have an idle pop misfire.

I've checked the TSB's related -- fuel composition sensor plug -- cam sensor jumper harness -- AC pressure sensor -- etc. Cant figure this one out.

Truck was cammed - a month ago, and had no issues until this. PCV is temporarily venting to atmosphere while a catch can comes.

Log below, not sure it will be much help
Thx.

Attachment 159209

Did you check your actual MAF sensor itself? Looks like it's just failing. Check wherever that circuit gets it's ground from as well.

Quote:

---

Originally Posted by bmpcamry09

Did you check your actual MAF sensor itself? Looks like it's just failing. Check wherever that circuit gets it's ground from as well.

---

Appreciate the reply!

I certainly did check the MAF sensor. Pins are good, connector etc. All the pins have proper voltages/signal/ground etc. VCM scanner also is logging the data correctly, indicating that the sensors in the multifunction unit are all working properly. I did even install a new sensor to verify it... same issues.

The ground specifically is the one on the back of the pass cylinder head, it is indeed attached and has good ground to battery.

After doing more diag on it, i've almost come to the conclusion that there is an issue with the ECM... Driving the vehicle, it has no codes. but randomly will display them. Then you re-scan, and they are gone...

Sounds like you are moving the right direction. Take that ground wire off. Make sure mating surfaces are clean. Give it a good tug in your hands to make sure it?s not brittle with green crusties inside. Have you back probed at the PCM connectors for the same circuits yet? Check for continuity. Make sure readings are the same as what your getting at the actual MAF.