2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1759
Action Taken When the DTC Sets
* DTCs P0989 and P0990 are Type C DTCs.
* The TCM freezes transmission adaptive functions for the reverse and low clutch and the 4-5-6 clutch.
Conditions for Clearing the DTC
DTCs P0989 and P0990 are Type C DTCs.
Diagnostic Aids
A TFP switch may malfunction due to normal debris in the transmission fluid causing a TFP Switch DTC to intermittently set. This type of failure
should not be immediately noticeable to a customer, as the switch outputs are used for shift adaptives and do not cause transmission symptoms
unless the switch malfunctions continuously for an extended period of time.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Diagrams)
Description and Operation
* Transmission General Description (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Description and
Operation/6T70/6T75 - Automatic Transmission/Transmission General Description)
* Electronic Component Description (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Description and
Operation/6T70/6T75 - Automatic Transmission/Electronic Component Description) for control solenoid (w/body and TCM) valve assembly
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Special Tools
DT-47825-20 - Jumper Harness
Circuit/System Verification
1. If there are any other transmission related DTCs set, diagnose those DTCs first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle (
See: Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
2. Engine idling in Park with parking brake applied, and drive wheels chocked.
3. Monitor the TFP Switch 1, TFP Switch 3, TFP Switch 4, and TFP Switch 5 parameters with a scan tool.
4. Place the gear select lever in Park, Reverse, and Neutral range. Verify the TFP Switch 1, TFP Switch 3, TFP Switch 4, and TFP Switch 5
parameter states are correct for each range. Refer to Transmission Fluid Pressure Switch Logic (See: Specifications/Mechanical
Specifications/Automatic Transmission/Transaxle/System Specifications/6T70/6T75 - Automatic Transmission/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, TFP Switch 3, TFP Switch 4, and TFP Switch 5 parameter states are correct for each range. Refer to Transmission Fluid Pressure
Switch Logic (See: Specifications/Mechanical Specifications/Automatic Transmission/Transaxle/System Specifications/6T70/6T75 -
Automatic Transmission/Transmission Fluid Pressure Switch Logic).
6. Operate the vehicle within the conditions 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. 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).
2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (See: Transmission and Drivetrain/Automatic
Transmission/Transaxle/Testing and Inspection/Component Tests and General Diagnostics/6T70/6T75 - Automatic Transmission/Control
Solenoid Valve and Transmission Control Module Assembly Inspection).
3. Place the control solenoid valve assembly on a clean work surface near the transmission assembly.
4. Connect DT-47825-20 - jumper harness between the vehicle wire harness electrical connector, and the control solenoid valve assembly
electrical connector.
5. Ignition ON, verify with a scan tool that the TFP Switch 1, TFP Switch 3, TFP Switch 4, and TFP Switch 5 parameters changes states when
gently pushing on each TFP switch with the eraser end of a pencil.
