2010 Cadillac CTS Sedan AWD V6-3.6L Page 1861
* The ECM detects that the voltage difference between APP sensor 1 and 2 is greater than 1.70 V with a fully pressed pedal.
* The ECM detects that the voltage difference between APP sensor 1 and 2 is greater than 0.04 V when APP sensor 1 is greater than 1.17 V.
* Any of the above conditions exist for greater than 1 second, or a cumulative of 10 s.
Action Taken When the DTC Sets
DTCs P2122, P2123, P2127, P2128, and P2138 are Type A DTCs.
Conditions for Clearing the DTC
DTCs P2122, P2123, P2127, P2128, and P2138 are Type A DTCs.
Diagnostic Aids
Test the current output of the 5 V reference circuits if you suspect high resistance in the circuit. The current output should be greater than 80 mA
for APP 1 and greater than 50 mA for APP 2.
Reference Information
Schematic Reference
Engine Controls Schematics (LLT) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics
(LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Throttle Actuator Control (TAC) System Description (See: Powertrain Management/Computers and Control Systems/Description and
Operation/Throttle Actuator Control (TAC) System Description)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
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
Circuit/System Verification
1. Ignition ON, observe the DTC information with a scan tool. DTC P0651, P0652, P0653, P0697, P0698, or P0699 should not be set.
瀚慖f a DTC is set, refer to DTC P0641-P0643, P0651-P0653, or P0697-P0699 (ECM, LLT) ( See: P Code Charts/P0641).
2. Observe the scan tool APP Sensor 1 and 2 voltage parameters. Verify both of the APP sensor voltages are between 0.4-4.5 V.
3. Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure
several times. DTCs P2122, P2123, P2127, P2128, or P2138 should not set.
4. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. DTCs
P2122, P2123, P2127, P2128, or P2138 should not set.
5. 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
1. Ignition OFF, remove the fuse that supplies B+ to terminal 56 X2 of the ECM.
2. Disconnect the harness connector at the Accelerator Pedal Assembly.
3. Test for less than 5 ohm between the appropriate low reference circuit listed below and ground.
* APP sensor 1 terminal D or 4
* APP sensor 2 terminal A or 5
瀚慖f greater than the specified range, test the low reference circuit for a short to voltage, or an open/high resistance. If the
circuit/connections test normal, replace the engine control module.
