P1DB6

P1DB6-VEHICLE SPEED SIGNAL PERFORMANCE

For a complete wiring diagram Refer to the Wiring Information.

Theory of Operation

The purpose of the monitoring is to detect rationality failures of the input speed and output speed sensor signals as well as the wheel speed and engine speed CAN signals. There are three categories of rationalities which include: Multi sensor comparisons of up to three signals (input, output and wheel speed). Monitoring of the gradient of the input speed signal. Double failure monitoring to determine unique failure situations which could require unique limp-in functionality.

- When Monitored:
Continuously when the vehicle is moving and the transmission is in a fixed gear.

- Set Condition:
The failure is detected if the input speed gradient is less than a threshold for a calibrated amount of time.





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

1. CHECK DTC IS CURRENT
1. Turn the ignition ON, Engine Not Running.
2. With the scan tool, select View DTCs.

NOTE: Check for Bus Communication DTCs. If no Bus or Communication DTCs are set, check for active DTCs stored in the Anti-Lock Brake Module. All communication DTCs or VSS DTCs in the Anti-Lock Brake Module must be properly diagnosed before continuing.

3. Start the engine.
4. Allow the engine to reach normal operating temperature.
5. With the scan tool, select View DTCs.

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 set by reviewing the Freeze Frame data.

Is the DTC Active or Pending at this time?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

2. INTERNAL TRANSMISSION
1. This DTC is an indication of a internal transmission failure.
2. Remove the Transmission Oil Pan and inspect for excessive debris such as clutch friction material or metal contamination.

Is there any indication of an internal transmission failure?

Yes

- Repair internal transmission as necessary. 8HP45 Automatic Transmission - Disassembly.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.

No

- Using the schematics as a guide, check the Transmission Control Module A (TCMA) terminals for corrosion, damage or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the TCMA. Valve Body - Removal.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.