P0501

Diagnostic Chart:

CIRCUIT DESCRIPTION
The speed sensor circuit consists of a magnetic induction type sensor, a vehicle speed sensor buffer module and wiring. Gear teeth pressed on the output shaft induce 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, cruise control, antilock brake and Powertrain Control Module (PCM). The buffer sends two different signals to the PCM. This is a type D DTC.

CONDITIONS FOR SETTING THE DTC
- Vehicle speed greater than 20 mph.
- Four wheel low not selected.
- VSS buffer calculated speed is less than halt the transmission calculated speed.
or
- VSS butter calculated speed is greater than transmission calculated speed by 20 mph.
- All 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 when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (16O°F) that same ignition cycle.

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

TEST DESCRIPTION
Number(s) below refer to number(s) on the Diagnostic Table.

3. This tests for B+ at VSS buffer.
4. This tests for proper ground path for vehicle speed sensor signal buffer.