P0501-VEHICLE SPEED SENSOR 1 PERFORMANCE





For a complete wiring diagram Refer to Section 8W.

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 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
  
PCM
  

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).



Diagnostic Test

1.ACTIVE DTC



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.





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 2


No

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.







Were any problems found?

Yes


No
  • Go To 3

3.PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.




Were there any problems found?

Yes


No