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Eric, Automotive Repair Shop Manager
Category: Chevy
Satisfied Customers: 29737
Experience:  20+ yrs. experience as repair shop manager and technician.
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I have engine code PO 641 Car barely runs Idols up-and-down

Customer Question

I have engine code PO 641 Car barely runs Idols up-and-down stalls
Submitted: 3 months ago.
Category: Chevy
Expert:  Eric replied 3 months ago.


DTC P0641 CIRCUIT DESCRIPTION The powertrain control module (PCM) provides 5 volts to the following sensors: - The manifold absolute pressure (MAP) sensor

- The exhaust gas recirculation (EGR) valve

- The fuel tank pressure (FTP) sensor

- The throttle position (TP) sensor

A circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The PCM monitors the voltage on the 5-volt reference circuit. If the PCM detects that the voltage is out of tolerance, DTC P0641 sets

Either one of the sensors mentioned above or pcm is faulty, or a short in the 5v reference wire going to one of the components.

You will need a full function scan tool, voltmeter and a good working knowledge of reading wiring schematics and automotive electrical systems to diagnose yourself and then repair.

I will need to know the engine size - 3.4, 3.8 or 3.8 supercharged engine in order to get you the proper wiring schematics and testing procedure

Expert:  Eric replied 3 months ago.

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