2010 Cadillac CTS Sedan AWD V6-3.0L Page 1838
The ECM detects that the APP sensor 2 voltage is less than 0.32 volt for less than 1 second.
P2128
The ECM detects that the APP sensor 2 voltage is greater than 2.6 volts for less than 1 second.
P2138
The ECM detects that APP sensor 1 and APP sensor 2 disagree greater than 10 percent for less than 1 second.
OR
The ECM detects that both APP sensor 1 and APP sensor 2 are 5 percent greater than the learned minimum position for less than 1 second.
Action Taken When the DTC Sets
* DTCs P2122, P2123, P2127, P2128, and P2138 are type A DTCs.
* The ECM commands the TAC system to operate in a Reduced Engine Power mode.
Conditions for Clearing the DTC
DTCs P2122, P2123, P2127, P2128, and P2138 are type A DTCs.
Diagnostic Aids
* If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected.
* The scan tool 5 volt reference parameter should display between 4.8-5.2 volts.
* A high resistance condition on the accelerator pedal position circuits could cause a DTC to set.
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. Verify DTCs P0697 or P06A3 are not set.
瀚慖f a DTC is set, refer to DTC P0641, P0651, P0697, or P06A3 (ECM, LF1) (See: P Code Charts/P0641) for further diagnosis.
2. Ignition ON, observe the scan tool Accelerator Pedal Position percentage parameter. The scan tool should display 0 percent.
3. Observe the scan tool APP Sensor 1 and 2 Agree/Disagree parameter while performing the following tests:
* Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the
procedure several times.
* Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times.
