4L80E , 4L85E Automatic Transmission DTC P0706 and Vehicle May Not Start - kw 6.0 8.1 LQ4 L18 no crankMIL

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

The 4L80E/4L85E may set a DTC P0706 (Transmission Range Switch Performance) and exhibit a no start condition.

Install the latest PCM calibration titled "New calibration to reduce the potential for setting P0706. Also addresses 3-2 downshift feel." With the new calibration, if the P0706 diagnostic fails, the software assumes Park if the engine is not running. If the engine is running, software uses PSM (pressure switch manifold) as backup.

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Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

(03 - CHEVROLET SILVERADO ) and (03 - CHEVROLET SUBURBAN ) and (03 - CHEVROLET AVALANCHE ) and (03 - CHEVROLET EXPRESS ) and (03 - GMC SIERRA ) and (03 - GMC YUKON XL ) and (03 - GMC SAVANA )

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