P0725 ENGINE SPEED SENSOR CIRCUIT

When Monitored and Set Condition:

When Monitored: Continuously with engine running.
Set Condition: This code is set when the engine speed sensed by the Transmission is less than 400 RPM and the engine is running (As reported by the PCM over the communication bus) for 2 seconds. This DTC can take up to five minutes of problem identification before illuminating the MIL.

POSSIBLE CAUSES

• RELATED ENGINE DTC'S PRESENT
• POWERTRAIN CONTROL MODULE
• INTERMITTENT WIRING AND CONNECTORS

DIAGNOSTIC PROCEDURE

NOTE: Low fluid level can be the cause of many transmission problems. If the fluid level is low locate and repair the leak then check and adjust the fluid level. Refer to appropriate AUTOMATIC TRANSMISSION article.

NOTE: Always perform diagnostics with a fully charged battery to avoid false symptoms.NOTE: Diagnose 1 Trip Failures as a fully matured DTC.

NOTE: Verify flash level of Powertrain Controller. Some problems are corrected by software upgrades to the Transmission and Engine Systems.

NOTE: Due to the integration of the Powertrain and Transmission control modules - if a controller flash is performed it is necessary to perform STANDARD PROCEDURE - TCM QUICK LEARN and the STANDARD PROCEDURE - DRIVE LEARN . Failure to do so may result in shift quality complaints.

NOTE: Check for applicable TSB's that may apply.

1. With the DRBIII(R), read the engine DTC's. Check and repair all Engine DTC's prior to performing Transmission symptom diagnostics. With the DRBIII(R), read Transmission DTC's. Record all DTC's and 1 Trip Failures. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Repair as necessary. Perform the Shift Lever Position Test. If the test does not pass, refer to Symptom test for SYMPTOM: P0706-CHECK SHIFTER SIGNAL . For Gear Ratio DTC's, check and record all CVI's. Most DTC's set on start up but some must be set by driving the vehicle to ensure that all diagnostic monitors have run. Perform this procedure prior to Symptom diagnosis. Continue Go To 2
   NOTE: This is not a Transmission Input Speed Sensor DTC.
   NOTE: This counter only applies to the last DTC set.
2. Start the engine. Allow the engine to idle. With the DRBIII(R), check the STARTS SINCE SET counter for P0725. Is the STARTS SINCE SET counter for P0725 set at 0?
   No --> Go To 3
   Yes --> Go To 4
3. The conditions necessary to set this DTC are not present at this time. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit. Wiggle the wires while checking for shorts and open circuits. With the DRBIII(R), check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set. Were there any problems found?
   Yes --> Repair as necessary. Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 .
   No --> Test Complete.
4. Ignition on, engine not running. With the DRBIII(R), read Engine DTC's. Are there any Engine DTCs present?
   Yes --> Refer to the Powertrain category and perform the appropriate symptom. Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 .
   No --> Go To 5
5. Using the schematics as a guide, inspect the wiring and connectors. Repair as necessary. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, view repair.

Repair

Replace the Powertrain Control Module and perform STANDARD PROCEDURE - TCM QUICK LEARN . Refer to ELECTRONIC CONTROL MODULES . Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 .