* 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.
锟斤拷If 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.
6. Clear the DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC or within the conditions that you observed
from the Freeze Frame/Failure Records.
7. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P2120 or P2125 are not the only APP sensor DTCs set.
锟斤拷If DTC P2120 or P2125 are the only DTCs set, replace the ECM.
8. 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, disconnect the harness connector at the accelerator pedal.
2. Ignition OFF for 1 minute, test for less than 5 ohm between the appropriate low reference circuit terminal listed below and ground.
* APP sensor 1 terminal F or 4
* APP sensor 2 terminal A or 5
