P0725-ENGINE SPEED SENSOR CIRCUIT

For a complete wiring diagram Refer to Section 8W.

Theory of Operation


The PCM uses a dual port RAM internal to the controller to send the engine speed signal to the Transmission Control System. The calculated engine RPM is compared to a minimum and maximum value. If the PCM interprets this signal to be out of range when the engine is running the code is set. The MIL illuminates after 10 seconds of vehicle operation and the transmission system defaults to limp-in mode.


  • When Monitored:

    Whenever the engine is running.

  • Set Condition:

    The Engine RPM is less than 390 or greater than 8000 for more than 2 seconds while the engine is running.


Possible Causes
  
ENGINE DTCS PRESENT
  
POWERTRAIN CONTROL MODULE
  

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)



Diagnostic Test

1.CHECK IF THE DTC IS CURRENT


NOTE: This DTC is not a Transmission Input Speed Sensor DTC.




Is the status Active for this DTC or is the STARTS SINCE SET counter set at 0?

Yes
  • Go To 2


No
  • Go To 3

2.CHECK IF ENGINE DTCS ARE PRESENT



Are there any engine DTC's present?

Yes


No
  • Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply. If no problems are found, replace and program the PCM per the Service Information. With the scan tool, perform QUICK LEARN.
  • Perform 42RLE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

3.INTERMITTENT WIRING AND CONNECTORS







Were there any problems found?

Yes


No
  • Test Complete.