P0501

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
The speed sensor circuit consists of a magnetic induction type sensor, a vehicle speed sensor buffer module and wiring. The gear teeth pressed on the output shaft induces an alternating current in the sensor. This signal is transmitted to the buffer. The buffer compensates for various axle ratios and converts the signal into a square wave for use by the speedometer, the cruise control, the anti lock brake and the PCM. The buffer sends two different signals to the PCM. This is a type D DTC.

CONDITIONS FOR SETTING THE DTC
^ The vehicle speed is greater than 20 mph.
^ The four wheel low is not selected.
^ The Vehicle Speed Sensor (VSS) buffer calculated speed is less than half of the transmission calculated speed.
OR
^ The VSS buffer calculated speed is greater than the transmission calculated speed by 20 mph.
^ All of the conditions must be met for 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
No cruise control.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A History DTC will clear after forty consecutive warm-up cycles during which the diagnostic does not fail (the coolant temperature has risen 5°C (40°F) from the start up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle).
^ Use of a Scan tool will clear the DTC codes.

DIAGNOSTIC AIDS
Check the connections at the VSS buffer and the PCM. Refer to 4L80E Diagnostic Trouble Codes if DTC P0722 or DTC P0723 is also set. P0722 P0723

TEST DESCRIPTION
The number(s) below refer to number(s) on the Diagnostic Table.
3. This tests for B+ at the VSS buffer.
4. This tests for a proper ground path for the vehicle speed sensor signal buffer.