P0501 - Vehicle Speed Sensor 1 Performance

For a complete wiring diagram, refer to appropriate Wiring Diagram.

Theory of Operation

The vehicle speed sensor rationality is a continuous test that monitors the vehicle speed sensor for lack of activity. The rationality will not run if a limp-in exists for MAP, Throttle Position, and Engine Coolant Temperature. If vehicle speed sensor is below a minimum threshold for a period of time after the vehicle is operated at a sufficient load, a failure will be indicated.

>>When Monitored:<< With the engine running, transmission not in park or neutral, brakes not applied, and engine RPM greater than 1500.
>>Set Condition:<< This code will set if no vehicle speed signal is received from the ABS Module for up to 120 seconds for 2 consecutive trips. Two Trip Fault. Three good trips to turn off the MIL.

Possible Causes
ACTIVE BUS OR COMMUNICATION DTCS
TIRE CIRCUMFERENCE
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .

Test Step 1 - ACTIVE DTC

Ignition on, engine not running.
With a scan tool, select View DTCs.

NOTE:

Check for any Bus Communication DTCs. If no Bus or Communication DTCs are set, check for active DTCs stored in the Anti-Lock Brake Module. Any bus or communication DTCs or VSS DTCs in the Anti-Lock Brake Module must be properly diagnosed before continuing.

Start the engine.
Allow the engine to reach normal operating temperature.
With a scan tool, select View DTCs.

NOTE:

It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

Is the DTC Active or Pending at this time?

Yes

Go to Test Step 2

Perform the Checking for an Intermittent DTC diagnostic procedure. Refer to CHECKING FOR AN INTERMITTENT DTC .

Test Step 2 - VISUAL INSPECTION

NOTE:

This code can set due to tire circumference differences and from the front or rear wheels being on a slippery surface while the opposite tires are not.

This code may also set on a hard acceleration on loose gravel or during other off road driving conditions.
Check tire pressure of all the tires.
Check tire wear on all the tires.
Ask the customer what the road and driving conditions were like when the fault set.

Were any problems found?

Yes

Repair as necessary. If the code set during a front OR rear wheel spin condition, no repair is necessary.
Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .

Go to Test Step 3

Test Step 3 - POWERTRAIN CONTROL MODULE (PCM)

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Vehicle Speed Sensors, ABS Module, and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Vehicle Speed Sensors, ABS Module, and Powertrain Control Module connectors.
Perform any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

Repair as necessary.
Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .

Replace and program the Powertrain Control Module (PCM). Refer to REMOVAL AND INSTALLATION .
Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .