Operation CHARM: Car repair manuals for everyone.
Home >> GMC Truck >> 2010 >> Terrain AWD V6-3.0L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P15A1

P15A1




DTC P15A1

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provide an overview of each diagnostic category.

DTC Descriptor
DTC P15A1
- Fuel Economy Mode Switch Performance

Diagnostic Fault Information





Circuit Description

The ECM supplies 5 V reference voltage, through the 5 V reference voltage circuit, to the fuel economy mode switch. This 5 V reference voltage causes current to flow through a series of resistors in the switch to the switch ground circuit. The ECM monitors the 5 V reference voltage through a discrete fuel economy mode switch signal circuit. When the switch button is momentarily pressed, the switch contacts allow the 5 V reference voltage signal to by-pass one of the resistors. The ECM detects the resulting voltage drop as a fuel economy mode request and sends a GMLAN message to the transmission control module (TCM) indicating the request. When the TCM receives the request, throttle progressions and transmission shift points are modified to optimize fuel efficiency. The instrument panel cluster (IPC) also receives the fuel economy mode request message from the ECM and illuminates the fuel economy mode indicator lamp. The fuel economy mode switch must be pressed for between 0.094-1.5 s to activate the fuel economy mode. Voltage on the signal wire is normally between 1.45-3.45 V with the switch depressed. When the switch is released, voltage on the signal wire is normally between 3.65-4.45 V.

Conditions for Running the DTC

* The ignition key is turned to ON.
* DTC P15A1 runs continuously when the above condition is met.

Conditions for Setting the DTC

The ECM detects that the voltage on the fuel economy mode switch signal wire is in an indeterminate range.

Action Taken When the DTC Sets

DTC P15A1 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P15A1 is a Type B DTC.

Reference Information
Schematic Reference

Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. If you cannot duplicate the condition, refer to Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections).
2. Verify that DTCs P159F and P015A0 are not set.

• If either or both of the DTCs are set, refer to Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions).

3. Engine running, observe the DTC information with a scan tool. DTC P15A1 should not set.
4. 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 before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the X1 harness connector at the Fuel Economy Mode switch.
2. Test for less than 5 ohm between the ground circuit terminal 1 of the harness connector and ground.

• If greater than the specified range, test the ground circuit for a high resistance and repair as necessary.

3. Measure between the 5 V reference voltage circuit terminal 3 of the switch and signal circuit terminal 4 of the switch for 266-294 ohm with a DMM.

• If the DMM does not measure between 266-294 ohm, replace the S87 fuel economy mode switch.

4. Measure between the 5 V reference voltage circuit terminal 3 of the switch and the ground circuit terminal 1 of the switch for 1,414-1,562 ohm with a DMM.

• If the DMM does not measure between 1,414-1,562 ohm, replace the S87 fuel economy mode switch.

5. With the fuel economy mode switch button depressed, measure between the 5 V reference voltage circuit terminal 3 of the switch and the ground circuit terminal 1 of the switch for 486-538 ohm with a DMM.

• If the DMM does not measure between 486-538 ohm, replace the S87 fuel economy mode switch.

6. Disconnect the X2 harness connector at the ECM.
7. Measure the 5 V reference voltage circuit, between terminal 14 of the ECM harness connector and terminal 3 of the fuel economy mode switch harness connector, for less than 5 ohm.

• If greater than the specified range, repair or replace the 5 V reference voltage circuit as necessary.

8. Measure the signal circuit, between terminal 50 of the ECM harness connector and terminal 4 of the fuel economy mode switch harness connector, for less than 5 ohm.

• If greater than the specified range, repair or replace the signal circuit as necessary.

9. If all circuits test normal, replace the K20 ECM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Fuel Economy Indicator Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup and programming

pro multis · About Operation CHARM