P1DB9

P1DB9-TCM ECU RESET - EXTENDED LOW VOLTAGE

For a complete wiring diagram Refer to the Wiring Information.

Theory of Operation

The purpose of the diagnostic is to ensure power flow after a Transmission Control Module (TCM) reset during a mechanical limp-in action or after an under voltage reset due to a low voltage condition of the TCM source voltage. The diagnostic is performed once during the reset initialization.

- When Monitored:
When a TCM reset occurred and the output speed is above a calibrated threshold.

- Set Condition:
The failure is detected if the mechanical limp-in action was active or an under voltage condition.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. 8HP45 Pre-Diagnostic Troubleshooting Procedure

1. CHECK FOR ENGINE CHARGING SYSTEM DTCS
1. With the scan tool, read Engine DTCs.

Are any Engine Charging System DTCs present?

Yes

- Repair Charging System DTCs before proceeding. Charging System.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.

No

- Go To 2

2. CHECK IF DTC IS CURRENT

NOTE: The Transmission Control Module stores under Environmental Data the transmission operating conditions when the DTC was set. Before clearing any DTCs, record all information pertaining to the DTC.

1. With the scan tool, CLEAR transmission DTCs.
2. Using the Environmental Data previously recorded, drive the vehicle and try to duplicate the condition in which the DTC set.

Does the DTC reset?

Yes

- Go To 3

No

- Go To 4

3. TRANSMISSION CONTROL MODULE ASSEMBLY (TCMA)

If there are no possible causes remaining, view repair.

Repair

- Using the schematics as a guide, check the TCMA terminals for corrosion, damage or terminal push out. Pay particular attention to power and ground circuits. Check Service Information Tune-ups or Service Bulletins for possible causes that may apply. If the DTC returns, replace and program the TCMA. Valve Body - Removal.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.

4. INTERMITTENT WIRING AND CONNECTORS
1. The conditions necessary to set this DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wires while checking for shorted and open circuits.

Where any problems found?

Yes

- Repair as necessary.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.

No

- Test Complete.