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 the transmission fluid level and condition is correct. Refer to Transmission Fluid Level and Condition Check .
- If the transmission fluid level and condition is not correct
Repair as necessary.
- Go to next step: If the transmission fluid level and condition is correct
- If the transmission fluid level and condition is not correct
- Operate the vehicle until normal engine temperature is reached.
- Verify with a scan tool the ECT Sensor parameter is less than 125°C (257°F).
- If greater than 125°C (257°F)
Refer to Symptoms - Engine Cooling .
- Go to next step: If less than 125°C (257°F)
- If greater than 125°C (257°F)
- Verify the scan tool Transmission Control Module Temperature is less than 142°C (287°F).
- If greater than 142°C (287°F)
Inspect the transmission fluid lines for being misrouted, kinked, or damage. Repair or replace as necessary. If the transmission fluid lines are OK, replace the Q8 Control Solenoid Valve Assembly.
- Go to next step: If less than 142°C (287°F)
- If greater than 142°C (287°F)
- 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
Replace the Q8 Control Solenoid Valve Assembly.
- Go to next step: If the DTC does not set
- If the DTC sets
- All OK.