Circuit/System Verification

WARNING: This page is about a different car, the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban 3500 HD, and 2018 Chevrolet Suburban. However, it is still accessible from the selected car via links, so may be relevant.

Verify DTC P0850, P0851 or P0852 is set.
- If any of the DTCs are set
  Refer to DTC P0850-P0852 .
- Go to next step: If none of the DTCs are set
Verify the range selector cable is adjusted correctly. Refer to Range Selector Lever Cable Adjustment .
- If the cable adjustment is not OK
  Adjust, repair or replace as necessary.
- Go to next step: If the cable adjustment is OK
Ignition ON.
Verify the scan tool parameter matches the Transmission Internal Mode Switch Logic table for each gear position. Refer to Transmission Internal Mode Switch Logic .
- If the parameter does not match
  Refer to Circuit/System Testing.
- Go to next step: If the parameter matches
Verify the scan tool engine control module Park/Neutral Switch parameter displays Park/Neutral with the gear shift lever in Park or Neutral and In Gear when in Reverse or Drive.
- If Park/Neutral or In Gear is not displayed
  Refer to Circuit/System Testing.
- Go to next step: If Park/Neutral or In Gear is displayed
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observe from the Freeze Frame/Failure Records data.
Verify the DTC does not set.
- If the DTC sets
  Refer to Circuit/System Testing.
- Go to next step: If the DTC does not set
All OK.