P0641

DTC P0641

CIRCUIT DESCRIPTION
The engine control module (ECM) provides 5 volts to the following sensors:
- The intake air temperature (IAT) sensor
- The manifold absolute pressure (MAP) sensor
- The air conditioning (A/C) refrigerant pressure sensor
- The fuel tank pressure (FTP) sensor
- The engine coolant temperature (ECT) sensor
- The throttle position (TP) sensor
- The fuel level sender

These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together inside the ECM. Therefore a circuit condition on one sensor 5-volt reference circuit may adversely affect the other sensor 5-volt reference circuits. This condition may result in diagnostic trouble codes (DTCs) for any or all of these sensors. The ECM monitors the voltage on the 5-volt reference circuit, if the ECM detects that the voltage is out of tolerance, DTC P0641 sets.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
The ECM detects a voltage out of tolerance condition on the 5-volt reference circuit.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

Steps 1-11:

Steps 12-13:

The number below refer to the number on the diagnostic table.
5. This step will determine if the TP sensor is responsible for a fault.