Vauxhall Workshop Service and Repair Manuals

DTC P071D

Diagnostic Instructions

DTC Descriptor

Diagnostic Fault Information

Circuit/System Description

The engine control module (ECM) supplies 5 V reference voltage, through the 5 V reference voltage circuit, to the fuel economy mode switch. The 5 V reference voltage causes current to flow through a series of resistors in the switch to the switch ground circuit. The ECM also supplies a signal circuit to detect voltage within the resistor network. When the fuel economy mode switch button is momentarily pressed, the switch contacts allow the current to by-pass one of the resistors. The ECM detects the resulting change in 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, and if operating conditions are correct, the transmission shift points are modified to optimise fuel efficiency. The TCM sends a confirmation message to the ECM and the instrument panel cluster (IPC) also receives the fuel economy mode request message from the TCM and illuminates the fuel economy mode indicator lamp.

Conditions for Running the DTC

Conditions for Setting the DTC

The TCM detects that the Economy Mode Switch has been continuously activated for 10 minutes.

Action Taken When the DTC Sets

Conditions for Clearing the DTC

DTC P071D is a Type C DTC.

Diagnostic Aids

Diagnose all communication and body DTCs first.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON, observe the scan tool ECM Fuel Economy Mode parameter. The parameter should display Inactive.
2. Command the Fuel Economy Mode ON and OFF with the Economy Mode switch and observe the Fuel Economy Mode parameter with a scan tool. The Fuel Economy Mode parameter should display Active or Inactive and change each time the Economy Mode switch is depressed.
3. After performing the above steps, verify that the DTC does not reset by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections .

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 Ω between the ground circuit terminal 1 of the harness connector and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance and repair as necessary.

3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 of the harness connector and ground.

⇒	If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

⇒	If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Observe the scan tool Fuel Economy Mode Switch parameter. The parameter should display Circuit Low Voltage.

⇒	If the parameter does not display the specified value, test the signal circuit for a short-circuit to voltage. If the circuit tests normal, replace the ECM.

5. Connect a 3 A fused jumper wire between 5 V reference circuit terminal 3 of the harness connector and signal circuit terminal 4 of the harness connector. Verify the scan tool Fuel Economy Mode Switch parameter displays Circuit High Voltage.

⇒	If the parameter does not display the specified value, test the signal circuit for an open/high resistance or a short-circuit to ground. If the circuit tests normal, replace the ECM.

6. Test for 266-294 Ω between the 5 V reference voltage circuit terminal 3 of the switch and the signal circuit terminal 4 of the switch.

⇒	If not the specified value, replace the economy mode switch

7. Test for 927-1024 Ω between signal circuit terminal 4 of the switch and low reference circuit terminal 1 of the switch.

⇒	If not the specified value, replace the economy mode switch.

8. With the fuel economy mode switch button depressed, test for 220-244 Ω between terminal 4 of the switch and terminal 1 of the switch.

⇒	If not the specified value, replace the economy mode switch.

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Manual Shift Detent Lever with Shaft Position Switch Assembly Replacement