2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2608
P2127
The ECM detects that the APP sensor 2 voltage is less than 0.32 V for greater than 0.2 s.
P2128
The ECM detects that the APP sensor 2 voltage is greater than 2.6 V for greater than 0.2 s.
P2138
The voltage difference between APP sensor 1 and APP sensor 2 exceeds a predetermined value for greater than 1 s.
Action Taken When the DTC Sets
* DTCs P2120, P2122, P2123, P2125, P2127, P2128, and P2138 are Type A DTCs.
* The control module commands the TAC system to operate in the Reduced Engine Power mode.
* A message center or an indicator displays Reduced Engine Power.
* Under certain conditions the control module commands the engine OFF.
Conditions for Clearing the MIL/DTC
DTCs P2120, P2122, P2123, P2125, P2127, P2128, and P2138 are Type A DTCs.
Diagnostic Aids
A high resistance condition on the accelerator pedal sensor circuits could cause a DTC to set.
Reference Information
Schematic Reference
Engine Controls Schematics (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/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/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 that DTC P0641 or P0651 are not set.
瀚慖f a DTC is set, refer to DTC P0641 or P0651 (ECM) (See: P Code Charts/P0641) for further diagnosis.
2. Observe the scan tool APP Sensor 1 and 2 voltage parameters. Verify both of the APP sensor voltages are between 0.32-4.75 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 P2120, P2122, P2123, P2125, 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
P2120, P2122, P2123, P2125, P2127, P2128, or P2138 should not set.
5. Observe the scan tool APP sensor 1 and 2 parameter. The scan tool should display Agree.
