P1DAD

P1DAD-INPUT SHAFT/OUTPUT SHAFT DIRECTION CORRELATION

For a complete wiring diagram Refer to the Wiring Information.

Theory of Operation

The purpose of the diagnostic is to detect an unwanted driving direction. A rationality check is performed between the measured directions of input speed and output speed signal and the calculated driving direction. The calculated driving direction is based on the commanded currents of the pressure regulators.

- When Monitored:
No failure of input speed or output speed sensor.

Input speed and output speed greater than a calibrated threshold.

Shift not in progress.

No clutch slip control function active.

- Set Condition:
The failure is detected if the measured directions of input speed and output speed signal do not correspond to the calculated driving direction for a calibrated amount of time.

Calculated Driving Direction is Forward

A failure is detected if input speed and output speed direction are different.

Calculated Driving Direction is Reverse

A failure is detected if input speed and output speed direction are the same.





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

1. CHECK TO SEE IF DTC IS CURRENT
1. Turn the ignition ON.
2. With the scan tool, CLEAR transmission DTCs.
3. Raise the vehicle on the hoist.
4. Start the engine.
5. With the scan tool, monitor the Output Speed Sensor RPM.
6. Firmly apply the brakes and place the gear selector in Drive.

WARNING: To avoid personal injury or death, keep hands and feet clear of rotating wheels.

7. Release the brakes and raise the engine rpm to allow the transmission to upshift to the 1-2 and 2-3 shift schedule.

Did the Output Speed Sensor display an rpm below 1,000?

Yes

- Go To 2

No

- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.

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. If no problems are found, replace and program the TCMA. Valve Body - Removal.
- Perform the TRANSMISSION VERIFICATION TEST. Verification Tests.