P0501

Diagram Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

A processed wheel speed sensor signal is sent from the ABS controller to the Theft Deterrent Module. The signal is then sent from the Theft Deterrent Module to the ECM. The ECM calculates vehicle speed from this signal. The Vehicle Speed/Theft Deterrent Signal circuit is pulled up to B+ within the ECM. This DTC covers this circuit from the Theft Deterrent Module to the ECM. The circuit from the ABS controller to the Theft Deterrent Module is covered by the ABS controller diagnostics.

CONDITIONS FOR RUNNING THE DTC

^ The engine speed is greater than 1960 RPM.

^ The engine load is greater than 3.2 ms but less than 4.2 ms.

CONDITIONS FOR SETTING THE DTC

The vehicle speed signal is less than 3 mph for longer than 5 seconds.

ACTION TAKEN WHEN THE DTC SETS

The ECM illuminates the Malfunction Indicator Lamp (MIL) and records the operating conditions in the Freeze Frame on the second consecutive drive trip that the diagnostic runs and fails.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The ECM turns off the MIL after three consecutive drive trips that the diagnostic runs and does not fail.

^ A History DTC clears after forty consecutive warm-up cycles if no failures report by this diagnostic or any other emission related diagnostic.

^ The ECM battery voltage is interrupted.

^ The scan tool clears the MIL/DTC.

DIAGNOSTIC AIDS

Use the Connector Test Adapter Kit J 35616-A for any test that requires probing the ECM harness connector or a component harness connector. Using this kit will prevent damage to the harness connector terminals.

Check for the following conditions:

^ Poor connections at the ECM or at the component. Inspect the harness connectors for any backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Refer to Overall Vehicle Information / Diagrams / Diagnostic Aids for Checking Terminal Contact procedure.

^ Misrouted harness. Inspect the harness in order to ensure that the harness is not routed too close to any high voltage wires such as spark plug leads, or too close to any high current devices such as the alternator, the motors, the solenoids, etc.

^ Damaged harness. Inspect the wiring harness for any damage. If the harness appears to be OK, observe the scan tool while moving the related connectors and the wiring harnesses. A change in the display may help in order to locate the fault.

If the sensor signal is only affected when the harness is moved at a component, and there is no problem with the harness or the connections, the component may be damaged.

Refer to Symptoms / Intermittents. Testing and Inspection

TEST DESCRIPTION

The number(s) below refer to the step numbers on the diagnostic table.

2. This step verifies that the fault is currently present.

3. The test light connected to B+ is used to simulate the B+ pull-up within the ECM. The DVM can be connected to the shaft of the test light and battery ground.

5. With the signal generator set as described, the scan tool should indicate greater than 0.00 mph. This is due to differences between the test signal and the processed signal from the ABS controller.