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Discussion Starter #1
Drove home last night about 100 miles and truck ran fine, started it up this morning and backed out of the garage. I had no throttle at all, smash the pedal to the floor and it doesn't do anything.

I have 2 codes
P0652 5-volt reference 2 circiut low voltage

P2228 Barometric Pressure Circuit Low.

I looked around and can't seem to find any broken wires. I found the the Baro sensor and it's wires are all good. could the sensor be bad? how do I test it.
I did some googling and it says the p0652 circuit ties the a/c pressure, engine oil pressure and fuel rail pressure. I guess I need to check those sensors but if anyone else has any suggestions I'd take the help.
 

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Go through your entire engine harness looking for any rubbed through wire insulation, corrosion, broken wire, even inspect the connector pins
 

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I’ve looked at most of the wires I can’t find ****. I checked the Accelerator Pedal Position sensor with my edge and it shows 10% max when I push it to the floor. Could it be the pedal sensor?
 

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Ok the 10% pedal seems due to the codes are putting it in some sort of limp mode. If I push the pedal with the truck NOT running I get 100% on my edge. I tried un plugging Engine Oil Pressure sensor, A/c Pressure, Fuel Rail Pressure and Turbo Vane Sensor all one at a time, restarting the truck in between. The Turbo Vane sensor when unplugged set off its own code (p2562) and the other codes do not come up. This allows me to rev the truck up and actually drive but the turbo vanes do not actuate correctly.
Thoughts?
 

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The 5V reference circuit is created by the ECM; The BARO needs that 5V reference circuit to correctly create it's output to the ECM.

Crapshoot guess is that you might need a new ECM, BUT don't just guess. Make sure this is really the problem before buying ANY parts.
 

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Discussion Starter #6
The 5V reference circuit is created by the ECM; The BARO needs that 5V reference circuit to correctly create it's output to the ECM.

Crapshoot guess is that you might need a new ECM, BUT don't just guess. Make sure this is really the problem before buying ANY parts.
I just went and manually actuated the vane sensor. sensor seems fine until I completely collapse it and it goes from 0% to 100% ??
I put the sensor back in and now the truck seems to start and run fine. :mad: Either the sensor has a ground fault and I straightened it out when I was fiddling with it or there is a short in the wiring that some how un shorted itself since this morning.

I can't trust it to keep driving it like that. If I have some time tomorrow my plan is to set up my edge in the engine bay and keep wiggling wires until the code hopefully comes back.
I have heard a few people mention ECM but people always come up with that when something freaky electrical happens. I may have to bite the bullet and take it to Chevy
 
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