P071D
DTC P071D
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 provides an overview of each diagnostic category.
DTC Descriptor
DTC P071D
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Transmission Sport Mode Switch circuit
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 optimize 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
* Engine speed is greater than 500 RPM for 5 seconds.
* Ignition voltage is between 9.0 volts and 19.0 volts.
Conditions for Setting the DTC
TCM detects that the Economy Mode Switch has been continuously activated for 10 minutes.
Action Taken When the DTC Sets
* DTC P071D is a type C DTC.
* TCM inhibits the sport mode shift pattern.
* TCM inhibits Tap Up/Down function.
* TCM inhibits manual shifting of forward gears.
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 (MH8) Electrical Diagrams
Connector End View Reference
* Component Connector End Views Sunshade - Left (DH6)
* Inline Harness Connector End Views Power Steering Control Harness to Forward Lamp Harness (NJ1)
Description and Operation
* Transmission General Description Transmission General Description
* Transmission Component and System Description Transmission Component and System Description
* Electronic Component Description Electronic Component Description
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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the Fuel Economy Mode parameter changes between Active and Inactive each time the S112 fuel economy mode switch is depressed.
• If the Fuel Economy Mode parameter does not display Inactive
Refer to Circuit/System Testing below.
• If the Fuel Economy Mode parameter displays Inactive
3. 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.
• If the Fuel Economy Mode parameter does not change from Inactive to Active, or Active to Inactive
Refer to Circuit/System Testing below.
• If the Fuel Economy Mode parameter changes from Inactive to Active, or Active to Inactive
4. 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 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 S112 fuel economy mode switch.
2. Test for less than 5 ohms between the ground circuit terminal 1 of the harness connector and ground.
• If 5 ohms or greater
Test for less than 2 ohms in the ground circuit, end to end.
• If 2 ohms or greater, repair the open/high resistance in the ground circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 5 ohms
3. Ignition ON.
4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 3 of the harness connector and ground.
• If less than 4.8 volts
1. Ignition OFF.
2. Test for less than 2 ohms in the 5 volt reference circuit, end to end.
• If 2 ohms or greater, repair the open/high resistance in the 5 volt reference circuit.
• If less than 2 ohms, replace the K20 engine control module.
• If greater than 5.2 volts
1. Ignition ON.
2. Test 5 volt reference circuit for a short to voltage.
• If a short to voltage is found, repair the 5 volt reference circuit wire.
• If a short to voltage is not found, replace the K20 engine control module.
• If between 4.8-5.2 volts
5. Observe the scan tool Fuel Economy Mode Switch parameter. The parameter should display Circuit Low Voltage.
• If the Fuel Economy Mode Switch parameter does not display Circuit Low Voltage
Test the Fuel Economy Mode signal circuit for a short to voltage.
• If a short to voltage is found in the signal circuit, repair the signal circuit wire.
• If a short to voltage is not found in the signal circuit, replace the K20 engine control module.
• If the Fuel Economy Mode Switch parameter displays Circuit Low Voltage
6. 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 Fuel Economy Mode Switch parameter does not display Circuit High Voltage
1. Ignition OFF.
2. Test for less than 2 ohms in the fuel economy mode signal circuit, end to end.
• If 2 ohms or greater, repair the open/high resistance in the signal circuit.
• If less than 2 ohms, replace the K20 engine control module.
• If the Fuel Economy Mode Switch parameter displays Circuit High Voltage
7. Ignition OFF.
8. Test for 266-294 ohms between the 5 V reference voltage circuit terminal 3 and the signal circuit terminal 4 on the S112 fuel economy mode switch.
• If not between 266-294 ohms
Replace the S112 fuel economy mode switch.
• If between 266-294 ohms
9. Test for 927-1024 ohms between signal circuit terminal 4 and low reference circuit terminal 1 on the S112 fuel economy mode switch.
• If not between 927-1024 ohms
Replace the S112 fuel economy mode switch.
• If between 927-1024 ohms
10. With the fuel economy mode switch button depressed, test for 220-244 ohms between terminal 4 and terminal 1 on the S112 fuel economy mode switch.
• If not between 220-244 ohms
Replace the S112 fuel economy mode switch.
• If between 220-244 ohms
11. Replace the K20 engine control module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
Manual Shift Detent Lever with Shaft Position Switch Assembly Replacement Service and Repair