2010 Cadillac CTS Sedan AWD V6-3.0L Page 1645
* J 21867 - Pressure Gauge
For equivalent regional tools, refer to Special Tools (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Tools and Equipment).
Circuit/System Verification
Note: If other DTCs are set, diagnose those DTCs first.
1. Engine idling in Park, with parking brake applied and drive wheels chocked.
2. Perform the Transmission Fluid Level and Condition Check (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing
and Inspection/Initial Inspection and Diagnostic Overview/Transmission Fluid Level and Condition Check) to verify correct fluid level and
condition.
3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Cleaning (See: Transmission and Drivetrain/Automatic
Transmission/Transaxle/Testing and Inspection/Component Tests and General Diagnostics/Control Solenoid Valve and Transmission Control
Module Assembly Cleaning) to dislodge debris and free up the valves.
4. Monitor the Transmission Fluid Pressure (TFP) switch 1 with a scan tool. Place the gear select lever in Park, Reverse, and Neutral range.
Verify the TFP switch 1 parameter states are correct for Park, Reverse, and Neutral. Refer to Transmission Fluid Pressure Switch Logic (
See: Specifications/Mechanical Specifications/Automatic Transmission/Transaxle/System Specifications/Transmission Fluid Pressure Switch
Logic).
5. Place the gear select lever in Drive range. Command the shift transmission with a scan tool through all forward ranges. Verify the TFP switch
1 parameter states are correct for all forward ranges. Refer to Transmission Fluid Pressure Switch Logic (See: Specifications/Mechanical
Specifications/Automatic Transmission/Transaxle/System Specifications/Transmission Fluid Pressure Switch Logic).
6. Engine idling in Park, verify with a scan tool the Transmission ISS/OSS supply voltage test status parameter displays OK.
7. Engine idling in Park. Observe the Transmission ISS parameter on the scan tool, while varying the engine speed. The Transmission ISS
parameter should vary with engine speed and not drop out.
8. Operate the vehicle at 16-32 km/h (10-20 mph) while observing the Transmission OSS parameter on the scan tool. The Transmission OSS
parameter should vary with the vehicle speed and not drop out.
Note: Perform a scan tool snapshot, during the road test.
9. Perform the Road Test (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing and Inspection/Initial Inspection and
Diagnostic Overview/Road Test). Verify the transmission operation performs as indicated in the road test instructions.
10. Review the scan tool snapshot data. Verify the following transmission data parameters display the correct values for each gear range:
* Transmission ISS
* Transmission OSS
* PC Solenoid 2
* TFP Switch 1
11. Operate the vehicle within the Condition for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the
conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note: You must perform the Circuit/System Verification first.
1. Perform the Line Pressure Check (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing and Inspection/Component
Tests and General Diagnostics/Line Pressure Check). Verify the transmission line pressures are within the specified ranges.
瀚慖f not within the specified ranges, refer to Fluid Pressure High or Low (See: Transmission and Drivetrain/Automatic
Transmission/Transaxle/Testing and Inspection/Symptom Related Diagnostic Procedures/Fluid Pressure High or Low).
2. Ignition OFF, remove the control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly
Replacement (See: Powertrain Management/Transmission Control Systems/Actuators and Solenoids - Transmission and
Drivetrain/Actuators and Solenoids - A/T/Shift Solenoid/Service and Repair).
3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test (See: Transmission and
Drivetrain/Automatic Transmission/Transaxle/Testing and Inspection/Component Tests and General Diagnostics/Control Solenoid Valve and
Transmission Control Module Assembly Solenoid Performance Test). Test all solenoids on the Q8 control solenoid valve assembly. A
pressure change should occur for each solenoid valve.
瀚慖f the Q8 control solenoid valve assembly does not pass the performance test, replace the Q8 control solenoid valve assembly.
4. Listed in the chart below, are conditions for each component that could set DTC P0776 or P0777. Carefully inspect each component for that
condition. Repair or replace as necessary.
