Any good electrical mechanics? 5v ref.

[Sirshredalot]

Hey ingo,

Had a nagging problem with my truck now for going on 4 years.

2001 gmc 3500 with an 8.1

Truck started throwing a p034x code, so i looked into a new sensor.....discontinued.

So i converted the timing set, cam sensor, and pigtail to a 2004 ls2 style setup....replaced the new cam sensor and pigtail twice...ecm once with a rebuild just as a wag.

Wasnt getting 5v reference with the new ecm to this particular circuit so i put the old one back in..although i had 5v ref at the map sensor.

Have since replaced all the wiring in the circuit from the sensor back to the ecm...single lug crimp and heat shring with loom.

Still throws a code p0342.

Two bad sensors in a row?.killed them both with incorrect wiring? I can't find a conversion schematic but instead went with how the sensor was labeled, 0 + -.

Any insights are helpful, thanks

Shred

 

[rem788]

I don't have a wiring diagram but other sensors may share the 5 volt reference. I have seen codes set for sensors when other sensors were causing the problem by shorting the 5 volt reference to ground. The code for a different sensor sets first depending on sensor priority and testing sequence. Try unplugging the other sensors one at a time and see if the 5 volt reference returns to the cam sensor. If so, you have found the problem. If not, test the 5 volt sensor circuit for short to ground. The short could be anywhere in the circuit/wiring. If there is no short to ground, test for 5 volts at the ecm with all the sensors unplugged, if no 5 volts this would indicate an ECM problem. Before condemning the ECM, check all powers and grounds to the ECM. Good luck.

 

[DoggyDaddy]

 

[d.kaufman]

I don't have a wiring diagram but other sensors may share the 5 volt reference. I have seen codes set for sensors when other sensors were causing the problem by shorting the 5 volt reference to ground. The code for a different sensor sets first depending on sensor priority and testing sequence. Try unplugging the other sensors one at a time and see if the 5 volt reference returns to the cam sensor. If so, you have found the problem. If not, test the 5 volt sensor circuit for short to ground. The short could be anywhere in the circuit/wiring. If there is no short to ground, test for 5 volts at the ecm with all the sensors unplugged, if no 5 volts this would indicate an ECM problem. Before condemning the ECM, check all powers and grounds to the ECM. Good luck.

Good advice

 

[Sirshredalot]

Never thought about that.

Will give it a try, thanks

Shred

 

[Sirshredalot]

3rd cam sensor fixed it.

Two bad ones in a row where shorting the 5v signal.

Chinese crap

Thanks to all
Shred