2001 Dodge 2500, 5.9L

Driving one day and the engine light came on, and cruise control would not work. Code was for P0123: high voltage on throttle position sensor. I reset the code and everything works fine except cruise contol is not available at all. When I turn on the blower motor, the engine light comes again, same code.

The TPS seems ok with ohmeter.

I'm baffled. I suspected some type of ground fault, but everything checks out.

Any ideas?

Thanks.

does the engine lamp come on every time blower motor is turned on

might check the wires from the TPS back to the computer. IIRC, there have been people that have had isued with the TPS wire picking up stray voltage from being to close to things like spark plug wires, etc....

does the engine lamp come on every time blower motor is turned on

Yes every time.

might check the wires from the TPS back to the computer. IIRC, there have been people that have had isued with the TPS wire picking up stray voltage from being to close to things like spark plug wires, etc....

Good suggestion. I thought maybe the ground on the TPS was floating or open. That would give the high voltage. But I don't see why the cruise won't start working again when the code is reset and the blower off.

Does anyone out there know where I can get a wiring diagram?

Also, which fuse controls the crusie control?

Thanks

you should remove your lower dash panel and disconnect the bulkhead connector wich is the big white connector on the left of column loosen bolt holding it together and check for moisture in connector due to possible windshield leak if moisture is in there pcm gets voltage at capacitor that cannot completely discharge and computes wrong voltage internally

you should remove your lower dash panel and disconnect the bulkhead connector wich is the big white connector on the left of column loosen bolt holding it together and check for moisture in connector due to possible windshield leak if moisture is in there pcm gets voltage at capacitor that cannot completely discharge and computes wrong voltage internally

Thanks for the suggestion. I will try that tomorrow.
The windshield was replaced about a year ago...

Ok, I checked the connector under the dash, and it's dry as bone. That's not the problem.

The check engine light comes on when the AC comes on, not the blower motor. It's the AC clutch. I put a meter on the TPS wiper, and I see it jump up to 1 volt at idle when the AC clutch kicks in.

Any ideas?

Thanks

After many hours of troubleshooting, it turns out the computer is the problem, in case anyone else out there is having this problem, check the computer.