42RLE Automatic Transmission

P0726-ENGINE SPEED INPUT CIRCUIT RANGE/PERFORMANCE

For a complete wiring diagram refer to Diagrams/Electrical. Electrical Diagrams


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.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. 42RLE - Pre-Diagnostic Troubleshooting Procedure



Diagnostic Test


1. CHECK IF THE DTC IS CURRENT

Start the engine.


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

With the scan tool, read DTCs.

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

With the scan tool, read engine DTCs.

Are there any engine DTCs present?

Yes

- Refer to Engine Electrical Diagnostics and perform the appropriate diagnostic procedure.
- Perform 42RLE TRANSMISSION VERIFICATION TEST. 42RLE Transmission Verification Test

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. With the scan tool, perform QUICK LEARN.
- Perform 42RLE TRANSMISSION VERIFICATION TEST. 42RLE Transmission Verification Test

3. INTERMITTENT WIRING AND CONNECTORS

The conditions necessary to set the DTC are not present at this time.

Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.

Wiggle the wiring and connectors while checking for shorted and open circuits.

With the scan tool, check the DTC EVENT DATA to help identify the conditions in which the DTC was set.

Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform 42RLE TRANSMISSION VERIFICATION TEST. 42RLE Transmission Verification Test

No

- Test Complete.