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Contents Wiring diagrams Section: Engine Control Systems All sections

Hybrid Engine Controls - DTC p0a1e to p1a8f Chevrolet Malibu VII

Engine Control Systems ~8018 words

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit/System Description

The internal fault detection is handled inside the starter/generator control module (SGCM). No external circuits are involved.

Conditions for Running the DTC

Engine ON.

Conditions for Setting the DTC

The SGCM detects an internal ECU malfunction.

Action Taken When the DTC Sets

Hybrid system disabled.

Conditions for Clearing the DTC

  1. The condition responsible for setting the DTC no longer exists.
  2. The ignition must be cycled before the DTC can be cleared.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. With a scan tool, clear the DTC.
  2. Cycle the ignition switch from OFF to RUN several times.
  3. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset.
  4. If the DTC resets, replace the SGCM.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
SignalP0A38P0A39P0A39
Low referenceP0A39

The starter/generator control module (SGCM) monitors the performance of the motor generator temperature sensor to detect if it is within range of the other temperature sensors, by comparing it to other temperature sensors it controls.

The engine is running.

Power inverter module (PIM) TEMP 1, PIM TEMP 2, auxiliary power module (APM) TEMP, Board TEMP, motor/generator unit (MGU) TEMP greater than 30°C (80°F) and engine OFF timer greater than 480 minutes of start up.

Hybrid system torque will be limited to 50 percent

The MGU temperature sensor returns normal range for 10 seconds

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Verify DTCs P0A38 or P0A39 are not set. If P0A38 or P0A39 are set diagnose those first.
  2. Ignition OFF, disconnect harness connectors from the SGCM. Refer to «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  3. Test for 120 - 125 kohms between the signal circuit SGCM X2 terminal 2 and the low reference circuit terminal 14. If within the specified range, replace the SGCM.
  4. Disconnect the 7 pin X1 connector at the MGU. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  5. Test for infinite resistance between the SGCM X2 connector terminal 2 and ground. If less than the specified value, test the circuit for short to ground.
  6. Test for less than 1 ohm between the SGCM X2 connector terminal 2 and the MGU X1 connector terminal G. If greater than the specified value, test the circuit for an open/high resistance.
  7. Test for less than 1 ohm between SGCM X2 connector terminal 14 and the MGU X1 connector terminal F. If greater than the specified value, test the circuit for an open/high resistance.
  8. If circuits test normal, replace the MGU.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) for MGU replacement
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
SignalP0A38P0A39P0A39
Low referenceP0A39

The starter/generator control module (SGCM) monitors to detect if the motor generator temperature sensor is shorted to ground, shorted to voltage or open.

The engine is running.

P0A38

  1. Sensor output voltage less than 0.2 volt for 1 second.
  2. Temperature is greater than 215°C (419°F) for 1 second.

P0A39

  1. Sensor output voltage greater than 3.95 volts for 1 second.
  2. Temperature is less than -20°C (-4°F) for 1 second.

P0A38, P0A39

Hybrid system torque will be limited to 50 percent

The MGU temperature sensor returns normal range for 10 seconds

Possible internal temperature sensor signal circuit short to ground.

Possible internal temperature sensor signal circuit short to voltage or open.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect harness connectors from the SGCM. Refer to «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  2. Test for 120-125 k ohms between the signal circuit SGCM X2 terminal 2 and the low reference circuit X2 terminal 14. If not within the specified range, test the signal circuit for short to ground or the signal circuit shorted to the low reference circuit. If the circuits test normal, replace the SGCM.
  3. Disconnect the connectors at the MGU. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  4. Test for less than 1 ohm between the SGCM X2 connector terminal 2 and the MGU X1 connector terminal G. If greater than the specified value, test the signal circuit for an open/high resistance or short to voltage.
  5. Test for less than 1 ohm between SGCM X2 connector terminal 14 and the MGU X1 connector terminal F. If greater than the specified value, repair the open/high resistance.
  6. If circuits test normal, replace the MGU.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) for MGU replacement
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors the motor generator unit (MGU) temperature sensor for an overtemperature condition.

The engine is running.

MGU temperature is greater than 205°C (401°F) for 1 second.

Stop PWM (MGU shutdown)

MGU temperature is less than 150°C (212°F) for 3 seconds.

Diagnostic Aids

Possible MGU fan failure caused by obstructions, blockage to the vents or damaged fan.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Perform the «Hybrid Battery Service Disconnect/Connect»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#hybrid-energy-storage-system-repair-instructions) .
  2. Inspect the connection of 3 phase cables for the proper torque. Refer to «Fastener Tightening Specifications»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-specifications__fastener-tightening-specifications) .
  1. If the 3 phase cables are within torque specifications, replace the MGU.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Generator with Starter Replacement for MGU replacement.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The motor generator unit (MGU) position sensor is used for determining motor control of the MGU. The motor control consists of the angular position and speed of the MGU. The rotor is bolted on the MGU shaft, the stator is bolted on the MGU bracket and the sensor circuit is soldered on the motor control board in the starter/generator control module (SGCM). The SGCM monitors the position sensor circuit to detect a converter error (loss of speed signal or tracking).

The engine is running.

R/D converter error (loss of signal or tracking) for 100 ms

Stop PWM (MGU shutdown)

Clears 30 seconds after cycle wake up signal.

  1. Possible internal sensor short to ground, short to voltage or open/high resistance.
  2. Possible MGU or SGCM fault
  3. Possible wiring harness short to ground, short to voltage or open/high resistance.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Disconnect the MGU X2 and the SGCM X2 connectors. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) and «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  2. Test the circuits in the SGCM to MGU Terminal Reference Table as indicated below. Also test these circuits for short to ground. If any of the circuits are not within specification, check for an open/high resistance or short to ground.
  3. Reconnect SGCM connector X2.
  4. Test the circuits in the MGU to SGCM Specification Table to ground as indicated below. If any of the circuits are not within the specified range, replace the SGCM.
  5. Reconnect the MGU X2 connector and disconnect the SGCM X2 connector. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) and «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  6. Test the circuits in the SGCM to MGU Specification Table as indicated below. If all circuits test normal, replace the MGU.
MGU Connector/TerminalSCGM Connector/TerminalMinimum ResistanceMaximum Resistance
Harness Continuity Test
BX2/7Less than 1 ohm
CX2/6Less than 1 ohm
DX2/4Less than 1 ohm
EX2/17Less than 1 ohm
FX2/20Less than 1 ohm
GX2/19Less than 1 ohm
HX2/5Less than 1 ohm

SGCM to MGU Terminal Reference Table

MGU Connector/TerminalSignal NameMinimum ResistanceMaximum Resistance
Measurements made to ground. SGCM connected and MGU disconnected.
DREZ1.6k ohms2k ohms
HREZ+1.6k ohms2k ohms
CREZ3Over 1 M ohm
BREZ4Over 1 M ohm
EREZGS (GND)Less than 5 ohm
GREZ1Over 1 M ohm
FX2/5Over 1 M ohm

MGU to SGCM Specification Table

SGCM Connector/TerminalSGCM Connector/TerminalMinimum ResistanceMaximum Resistance
MGU connected and SGCM disconnected.
X2/4X2/520.1 ohms26.7 ohms
X2/6X2/1932.4 ohms43.0 ohms
X2/7X2/2032.9 ohms43.5 ohms
X2/4X2/6Over 1 meg ohm
X2/4X2/7Over 1 meg ohm
X2/6X2/7Over 1 meg ohm

SGCM to MGU Specification Table

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) for MGU replacement
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors the motor generator unit (MGU) angle position sensor circuit. to detect a fault in the angle data.

The engine is running.

(Data error) R/D IC angle data does not match with micro computer angle data. Self check fault when initial sequence (initialization error).

Stop PWM (MGU shutdown)

Clears 30 seconds after cycle wakeup signal.

Possible electrical failure at RD circuit

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Disconnect the MGU X2 and the SGCM X2 connectors. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) and «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  2. Test the circuits in the SGCM to MGU Terminal Reference Table as indicated below. Also test these circuits for short to ground. If any of the circuits are not within specification, repair the open/high resistance or short to ground.
  3. Reconnect MGU connector X2.
  4. Test the circuits in the MGU to SGCM Specification Table to ground as indicated below. If all circuits test normal, replace the MGU.
  5. Reconnect the MGU X2 connector and disconnect the SGCM X2 connector. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) and «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  6. Test the circuits in the SGCM to MGU Specification Table as indicated below. If any of the circuits are not within the specified range, replace the SGCM.
MGU Connector/TerminalSCGM Connector/TerminalMinimum ResistanceMaximum Resistance
Harness Continuity Test
BX2/7Less than 1 ohm
CX2/6Less than 1 ohm
DX2/4Less than 1 ohm
EX2/17Less than 1 ohm
FX2/20Less than 1 ohm
GX2/19Less than 1 ohm
HX2/5Less than 1 ohm

SGCM to MGU Terminal Reference Table

MGU Connector/TerminalSignal NameMinimum ResistanceMaximum Resistance
Measurements made to ground. SGCM disconnected and MGU connected.
DREZ1.6k ohms2k ohms
HREZ+1.6k ohms2k ohms
CREZ3Over 1 M ohm
BREZ4Over 1 M ohm
EREZGS (GND)Less than 5 ohm
GREZ1Over 1 M ohm
FX2/5Over 1 M ohm

MGU to SGCM Specification Table

SGCM Connector/TerminalSGCM Connector/TerminalMinimum ResistanceMaximum Resistance
MGU disconnected and SGCM connected.
X2/4X2/520.1 ohms26.7 ohms
X2/6X2/1932.4 ohms43.0 ohms
X2/7X2/2032.9 ohms43.5 ohms
X2/4X2/6Over 1 M ohm
X2/4X2/7Over 1 M ohm
X2/6X2/7Over 1 M ohm

SGCM to MGU Specification Table

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) for MGU replacement
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The motor generator unit (MGU) position sensor is used for determining motor control of the MGU. The motor control consists of the angular position and speed of the MGU. The rotor is bolted on the MGU shaft, the stator is bolted on the MGU bracket and the sensor circuit is soldered on the motor control board in the starter/generator control module (SGCM). The SGCM monitors the position sensor circuit to detect an overspeed condition.

The engine is running.

Absolute motor speed is greater than 21,000 RPM for 10 ms.

Stop PWM (MGU shutdown)

Clears 30 seconds after cycle wake up signal.

Possible motor overspeed.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Disconnect the MGU X2 and the SGCM X2 connectors. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) and «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  2. Test the circuits in the SGCM to MGU Terminal Reference Table as indicated below. Also test these circuits for short to ground. If any of the circuits are not within specification, repair the open/high resistance or short to ground.
  3. Reconnect MGU connector X2.
  4. Test the circuits in the MGU to SGCM Specification Table to ground as indicated below. If all circuits test normal, replace the MGU.
  5. Reconnect the MGU X2 connector and disconnect the SGCM X2 connector. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) and «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  6. Test the circuits in the SGCM to MGU Specification Table as indicated below. If any of the circuits are not within the specified range, replace the SGCM.
MGU Connector/TerminalSCGM Connector/TerminalMinimum ResistanceMaximum Resistance
Harness Continuity Test
BX2/7Less than 1 ohm
CX2/6Less than 1 ohm
DX2/4Less than 1 ohm
EX2/17Less than 1 ohm
FX2/20Less than 1 ohm
GX2/19Less than 1 ohm
HX2/5Less than 1 ohm

SGCM to MGU Terminal Reference Table

MGU Connector/TerminalSignal NameMinimum ResistanceMaximum Resistance
Measurements made to ground. SGCM disconnected and MGU connected.
DREZ1.6k ohms2k ohms
HREZ+1.6k ohms2k ohms
CREZ3Over 1 M ohm
BREZ4Over 1 M ohm
EREZGS (GND)Less than 5 ohm
GREZ1Over 1 M ohm
FX2/5Over 1 M ohm

MGU to SGCM Specification Table

SGCM Connector/TerminalSGCM Connector/TerminalMinimum ResistanceMaximum Resistance
MGU disconnected and SGCM connected.
X2/4X2/520.1 ohms26.7 ohms
X2/6X2/1932.4 ohms43.0 ohms
X2/7X2/2032.9 ohms43.5 ohms
X2/4X2/6Over 1 M ohm
X2/4X2/7Over 1 M ohm
X2/6X2/7Over 1 M ohm

SGCM to MGU Specification Table

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) for MGU replacement
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) temperature sensor is used for system overheat protection. The SGCM monitors the board temperature sensor for an overtemperature condition.

The engine is running.

Board temperature is greater than 120°C (248°F) for 1 second.

  1. Stop PWM (MGU shutdown)
  2. APM PWM off

Board temperature is less than 120°C (248°F) for 3 seconds.

Possible engine or SGCM cooling system failure due to the following

  1. Restricted radiator air flow
  2. Restricted engine coolant flow
  3. Faulty thermostat
  4. Faulty engine water pump
  5. Inoperative SGCM coolant pump

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Verify the SGCM coolant pump operates.
  2. Ignition ON, command the scan tool SGCM coolant pump output control ON and OFF. If the SGCM coolant pump does not operate refer to «SGCM Coolant Pump Malfunction»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-dtc-p0a1e-to-p1a8f__sgcm-coolant-pump-malfunction) .
  3. Ignition ON, observe the scan tool SGCM temperature sensor parameters. If only the SGCM board temperature sensor reads high, replace the SGCM.

SGCM Coolant Pump Malfunction

  1. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
  2. Ignition ON, test for B+ between the B+ circuit terminal A and ground. If less than the specified value, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect a test lamp between the B+ circuit terminal A and the control circuit terminal B.
  4. Ignition ON, command the SGCM Coolant Pump Relay ON and OFF with a scan tool. The test lamp should turn On and OFF when commanded. If the test lamp does not turn ON and OFF when commanded, test the control circuit for an open/high resistance. If the circuit tests normal, replace the SGCM.
  5. If all circuits test normal, test or replace the SGCM coolant pump

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator Control Module Coolant Pump Replacement»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#hybrid-cooling-system-repair-instructions)
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The auxiliary power module (APM) current sensor is used for over current limitation (less than 150 A). The starter/generator control module (SGCM) monitors the current sensor to detect the failure of the APM current sensor circuit (performance monitor).

The engine is running.

APM current limit.

  1. Stop PWM (MGU shutdown).
  2. APM PWM off.
  1. APM current (IR 1) is restricted by maximum current (IR HI or IR LOW)
  2. In case of Buck mode: IR 1 - IR HI is greater than 39 A for 25 ms.
  3. In case of Boost mode: IR - IR LOW is greater than 39 A for 25 ms.
  4. IR 1: APM current, IR HI: APM buck mode current limit +130 A.
  5. IR LOW: APM boost mode current limit (-130 A).
  6. APM output voltage (V14OUT) is greater than 7 volts and 42-volt output voltage (42OUT) is greater than 28 volts.
  7. Clears 30 seconds after cycle wakeup signal.

Possible internal failure at current sensor.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. With a scan tool, clear the DTC.
  2. Ignition OFF, wait 30 seconds.
  3. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The auxiliary power module (APM) current sensor is used for over current limitation (less than 150A). The current sensor is soldered on the control board, near the APM 12-volt bus bar. The starter/generator control module (SGCM) monitors the current sensor for the following

  1. To detect the failure of the APM current sensor circuit (high)
  2. To detect the failure of the APM current sensor circuit (low)

If one of the above conditions is detected, the SGCM will set the appropriate DTC.

The engine is running.

P0A88

Sensor signal for APM is less than +0.5 volt (-376A) for 0.5 ms.

P0A89

Sensor signal for APM is greater than 4.5 volts (376A) for 0.5 ms.

APM PWM off

Clears 30 seconds after cycle wake up signal

Possible current sensor short to ground or open

Possible current sensor short to voltage

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. With a scan tool, clear the DTC.
  2. Ignition OFF, wait 30 seconds.
  3. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The auxiliary power module (APM) 12-volt output voltage is used for a 12-volt line APM output voltage control and a 12-volt line voltage sensor rationality check.

The engine is running.

12-volt output voltage is greater than 18 volts for 2 seconds.

APM PWM off.

In both the hardware and software faults, normal range for 160 ms.

  1. Battery cable open (load dump)
  2. Fuse/relay box electrical failures

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

WARNINGTo help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.
  1. Inspect for any open fuses.
  2. Inspect all the 12-volt battery connections for proper torque as follows: At Battery At SGCM At Fuse block Refer to «Fastener Tightening Specifications»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-specifications__fastener-tightening-specifications) .
  3. With a scan tool, clear the DTC.
  4. Ignition OFF, wait 30 seconds.
  5. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors the drive belt connection between the engine and the motor generator unit (MGU). If belt slip is detected, the DTC will set.

The engine is running.

The mechanical drive belt connection (belt slip) is detected.

The hybrid system is degraded.

  1. The diagnostic system has not been disabled.
  2. There are no crank sensor faults.
  3. There are no engine coolant temperature sensor faults.
  4. There are no mass air flow sensor faults.
  5. There are no intake air temperature sensor faults.
  6. There are no starter/generator temperature faults.
  7. There are no starter/generator position sensor faults.
  8. There are no starter/generator speed faults.
  9. There are no starter/generator torque delivered faults.

Possible belt tension or tensioner problem.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Inspect drive belt is not damaged. If damage is found, refer to «Symptoms - Engine Mechanical»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-diagnostic-information-and-procedures) .
  2. Perform the «Drive Belt Tensioner Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-diagnostic-information-and-procedures__drive-belt-tensioner-diagnosis) .
  3. If the engine drive belt and tensioner are within specifications, replace the MGU.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The auxiliary power module (APM) temperature sensor is used for overheat protection. The thermistor is located on the control board, near the phase APM power MOSFET. The starter/generator control module (SGCM) monitors the board temperature sensor for an APM overtemperature condition.

The engine is running.

APM temperature sensor is greater than 80°C (175°F) for 2 seconds.

APM PWM off

FET temperature for APM is less than 150°C (302°F) for 2.5 seconds.

Possible engine or SGCM cooling system failure due to the following

  1. Restricted radiator air flow
  2. Restricted engine coolant flow
  3. Faulty thermostat
  4. Faulty engine water pump
  5. Inoperative SGCM water pump

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Verify the SGCM coolant pump operates.
  2. Ignition ON, command the scan tool SGCM coolant pump output control ON and OFF. If the SGCM coolant pump does not operate refer to «Circuit/System Testing»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-dtc-p0a1e-to-p1a8f) , under SGCM Coolant Pump Malfunction.
  3. Inspect all 12-volt battery connections for a short to ground as follows: At battery At SGCM At fuse block
  4. If all connections are normal, replace the SGCM.

SGCM Coolant Pump Malfunction

  1. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
  2. Ignition ON, test for B+ between the B+ circuit terminal A and ground. If less than the specified value, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect a test lamp between the B+ circuit terminal A and the control circuit terminal B.
  4. Ignition ON, command the SGCM Coolant Pump Relay ON and OFF with a scan tool. The test lamp should turn On and OFF when commanded. If the test lamp does not turn ON and OFF when commanded, test the control circuit for an open/high resistance. If the circuit tests normal, replace the SGCM.
  5. If all circuits test normal, test or replace the SGCM coolant pump

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator Control Module Coolant Pump Replacement»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#hybrid-cooling-system-repair-instructions)
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter generator control module (SGCM) monitors the hybrid battery voltage to verify that the output voltage (36 volts) Is within normal operating value (above 22 volts). If the output voltage is not within this value, this DTC will set.

The engine is running.

36 volt output voltage is less than 22 volts for 2 seconds.

  1. Stop PWM (MGU shutdown)
  2. APM PWM off

36 volt output voltage increases to greater than 22 volts.

  1. Possible battery cable open
  2. Possible fuse/relay block electrical failure

Schematic Reference

  1. «Hybrid Controls Schematics»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#hybrid-engine-controls-wiring-schematics)
  2. «Hybrid Energy Storage Schematics»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#hybrid-energy-storage-system-wiring-schematics)

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Hybrid System Voltage parameter in the SGCM data list. The voltage should be greater than 22 volts. If the parameter displays less than the specified value, refer to SGCM 36 volt Output Terminal Circuit Low below.
  2. Ignition ON, observe the scan tool Hybrid System Voltage parameter in the BECM data list. The voltage should be greater than 22 volts. If the parameter displays less than the specified value, refer to «Hybrid Battery Pack Voltage Low»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-dtc-p0a1e-to-p1a8f__hybrid-battery-pack-voltage-low) .

SGCM 36 volt Output Terminal Circuit Low

  1. If DTC is history, refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures) .
  2. Ignition ON, test for greater than 22 volts at the SGCM battery positive 36 volt output voltage stud. If less than the specified value, test the 36 volt cable for an open/high resistance or short to ground.
  1. If greater than the specified value, replace the SGCM.

Hybrid Battery Pack Voltage Low

  1. If DTC is history, refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures) .
  2. Gain access to the hybrid battery pack. Refer to «Hybrid Battery Service Disconnect/Connect»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#hybrid-energy-storage-system-repair-instructions) .
  3. Ignition OFF, test battery pack voltage for greater than 22 volts. If less than the specified value, replace the battery pack.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator Battery Replacement»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#hybrid-energy-storage-system-repair-instructions)
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors connector X2 terminals 15 and 16. When the connector is disconnected, the SGCM capacitors are electrically connected to a discharge resistor.

The engine is running.

36-volt output voltage greater than 10 volts and discharge resistance error signal is ON for 1 second.

Hybrid system is disabled.

Clears 30 seconds after cycle wakeup signal.

Possible cable open or SGCM internal problem.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, inspect the SGCM X2 harness connector for poor connections, bent terminals or corrosion.
  2. Reinstall SGCM X2.
  3. Ignition ON, with a scan tool, clear the DTC.
  4. Ignition OFF, wait 30 seconds.
  5. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset.
  1. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors the internal torque value and compares it to the motor generator unit (MGU) delivered torque value. If the delivered torque is not within tolerance, the DTC will set.

The engine is running.

Torque error is greater than 10 N.m for 1 second.

Delivered torque (CAN data) = command torque.

Normal range for 1 second

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Disconnect harness connector X2 from the SGCM. Refer to «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  2. Test for 5-100 ohms between terminals 9 and 12. If within the specified range, replace the SGCM.
  3. Disconnect the X1 connector at the MGU. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  4. Test for less than 1 ohm between SGCM connector harness terminal 12 and the MGU connector harness terminal A. If greater than the specified range, test the circuit for open/high resistance.
  5. Test for less than 1 ohm between SGCM connector harness terminal 9 and the MGU X1 connector harness terminal C. If greater than the specified range, test the circuit for open/high resistance.
  6. If both circuits test normal, replace the MGU.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors to detect internal faults. If a fault is detected, the appropriate DTC will set.

The engine is running.

P1A63

The gate driver voltage fault signal is low or PWM logic error fault signal is low.

P1A69

RAM check error

P1A6A

RAM check error (calculated ROMSUM value does not match with defined value).

P1A6B

5 volt reference fault, 5 volt input AD value (2 byte) is out of the range for 100 ms.

P1A63, P1A69, P1A6A, P1A6B

  1. Stop PWM (MGU shutdown)
  2. APM PWM Off

Clears 30 seconds after cycle wake up signal.

Possible internal electrical failure of the SGCM.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, verify that the latest service software is installed.
  2. With a scan tool, clear the DTC.
  3. Ignition OFF, wait 30 seconds.
  4. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors to detect internal fault. If a fault is detected, the appropriate DTC will set.

The SGCM has received a wake up signal.

The SGCM has detected an internal fault.

The hybrid system is disabled.

The SGCM is successfully programmed.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. With a scan tool, clear the DTC.
  2. Ignition OFF, wait 30 seconds.
  3. If the DTC is resets, program the SGCM.
  4. Ignition ON, verify that the latest service software is installed.
  5. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors the system voltage sensor to detect for a shorted low or shorted high condition.

P1A6D, P1A6E

  1. The engine is running.
  2. Hybrid mode is active.

P1A6D

  1. Sensor output voltage is less than 0.2 volt (30.0 volts).
  2. The 12-volt power supply - 12-volt output voltage is greater than 5 volts for 0.5 ms.
  1. Sensor output voltage is greater than 3.84 volt (1.56 volts).
  2. The 12-volt power supply - 12-volt output voltage is greater than 5 volts for 0.5 ms.

Hybrid system is disabled.

Wake up signal is ON.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

P1A6D, P1A6E

  1. With a scan tool, clear the DTC.
  2. Ignition OFF, wait 30 seconds.
  3. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors to determine performance of the motor generator unit (MGU).

The AutoStop ready indication will be a DIC message that indicates the following two states

  1. AUTOSTOP AVAL (AutoStop Available)
  2. AUTOSTOP UNAVAIL (AutoStop Unavailable)

The engine control module (ECM) will send an AutoStop state message to the body control module (BCM). The BCM will transmit the AutoStop state message to the instrument panel cluster (IPC). If all of the following conditions are true the indicated state will be Avail, otherwise the state will be Unavail

  1. Vehicle speed of 4 mph exceeded (initially)
  2. Ambient temperature above -15°C (5°F)
  3. Hybrid and powertrain components temperatures in hybrid operational ranges Hybrid battery temperature is greater than 10°C (50°F) (approximate) and less than 50°C (122°F). Transmission fluid temperature is greater than 35°C (95°F) (ambient temperature less than 10°C (50°F). Transmission fluid temperature is greater than 20°C (68°F) (ambient temperature greater than 10°C ( 50°F). Transmission fluid temperature is less than 110°C (230°F). Engine coolant temperature is greater than 80°C (176°F) (ambient temperature less than 10°C ( 50°F). Engine coolant temperature is greater than 47°C (176°F) (ambient temperature greater than 10°C ( 50°F) Engine coolant is less than 121°C (250°F)
  4. Vehicle in Drive (No autostops in I, L or Reverse)
  5. HVAC compressor system request Engine ON = False
  6. Grade less than 18 percent
  7. Sufficient brake vacuum
  8. SOC is greater than required for AutoStop (70 percent).
  9. Battery discharge power capability is greater than minimum required for AutoStart (6200 watts).
  10. Acceptable 12 volt battery status (voltage, current, temperature)
  11. No wheel slip (ABS or Traction Control) active
  12. EVPR not running small leak test
  13. Hood is closed.
  14. Default action 1, 2, 3, or 4 not active

The engine is running.

The hybrid restart DTC will set when the following occurs

  1. After initial stop, release of the brake pedal does not initiate a restart. At this time the 12 volt system will automatically start the vehicle.
  2. After the next stop, if the engine will not turn off and then restart when the brake pedal is pressed and released, this will set DTC P1A6F. If this reoccurs after the next ignition cycle, the MIL will light.

Hybrid system is disabled.

The hybrid restart failed diagnostic is enabled under the following conditions

  1. Diagnostic system has not been disabled.
  2. Calibration to run this application is True.
  3. There are no belt slip faults.
  4. Ignition switch in Run/Crank position
  5. There are no MGU torque delivered faults.
  6. Fuel level is above 10 percent.

The scan tool ECM output control Starter Enable will override most of the conditions that are normally required to allow autostart. Although the vehicle may be started, there could still be conditions that are not allowing the vehicle to autostart when it is being operated under normal conditions. If unable to autostart, verification of the enabling criteria in Circuit/System Description is required to find possible criteria that is not enabling a autostart.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

WARNINGRefer to Road Test Warning .
  1. Use the scan tool ECM Starter Enable command output control to enable an autostart. If engine starts, road test the vehicle to confirm that the autostart is operating. Refer to «Diagnostic Aids»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-dtc-p0a1e-to-p1a8f) .
  2. Gain access to the following wiring connections: Starter/generator control module (SGCM) 36 volt and 3 phase connections. Refer to «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) . Motor generator unit (MGU) 3 phase cable connections. Refer to «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  3. Verify the above listed connections are within specifications. Refer to «Fastener Tightening Specifications»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-specifications__fastener-tightening-specifications) . If all connections are within specifications, replace the MGU.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors the performance to detect 12-volt DC wire electrical failure by comparing the 12-volt input to the 12-volt output values. If the difference is greater than 5 volts, the DTC sets.

  1. The engine is running.
  2. Hybrid mode is active.

The 12-volt power supply - 12-volt output voltage is greater than 5 volts for 119 ms and any fault during 15 seconds wait period.

  1. Stop PWM (MGU shutdown).
  2. APM PWM off.

Cycle wake up signal.

Possible 12-volt battery or APM voltage sensor stuck.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. With a scan tool, clear the DTC.
  2. Ignition OFF, wait 30 seconds.
  3. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors the temperature sensors to determine if the sensor is reading correctly, by comparing it to average of 3 other sensors after 480 minute soak.

The engine is running.

The average (PIMTEMP 1, PIMTEMP 2, APMTEMP) - BOARDTEMP is greater than 30°C (86°F)

  1. 50 percent maximum torque limit
  2. APM 50 percent maximum current output

Return to normal range for 10 seconds.

  1. Possible internal failure of the temperature sensor
  2. Restricted radiator air flow
  3. Restricted engine coolant flow
  4. Faulty thermostat
  5. Faulty engine water pump
  6. Inoperative SGCM coolant pump

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Verify the SGCM coolant pump operates.
  2. Ignition ON, command the scan tool SGCM coolant pump output control ON and OFF. If the SGCM coolant pump does not operate refer to «Circuit/System Testing»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-dtc-p0a1e-to-p1a8f) , under SGCM Coolant Pump Malfunction.
  3. Ignition ON, observe the scan tool SGCM temperature sensor parameters. If only the SGCM board temperature sensor reads high, replace the SGCM.

SGCM Coolant Pump Malfunction

  1. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
  2. Ignition ON, test for B+ between the B+ circuit terminal A and ground. If less than the specified value, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect a test lamp between the B+ circuit terminal A and the control circuit terminal B.
  4. Ignition ON, command the SGCM Coolant Pump Relay ON and OFF with a scan tool. The test lamp should turn On and OFF when commanded. If the test lamp does not turn ON and OFF when commanded, test the control circuit for an open/high resistance. If the circuit tests normal, replace the SGCM
  5. If all circuits test normal, test or replace the SGCM coolant pump

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator Control Module Coolant Pump Replacement»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#hybrid-cooling-system-repair-instructions)
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors the temperature sensor circuit to detect shorted low or high failure.

The engine is running.

P1A7C

The internal temperature sensor output voltage less than 0.2 volt for 1 second.

P1A7D

The internal temperature sensor output voltage greater than 4.6 volts for 1 second.

P1A7C, P1A7D

  1. 50 percent maximum torque limit.
  2. APM 50 percent maximum current output.

Return to normal range for 10 seconds.

Possible internal sensor short to ground or open.

Possible internal short to voltage or open.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Verify the SGCM coolant pump operates.
  2. Ignition ON, command the scan tool SGCM coolant pump output control ON and OFF. If the SGCM coolant pump does not operate refer to «Circuit/System Testing»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-dtc-p0a1e-to-p1a8f) , under SGCM Coolant Pump Malfunction.
  3. With a scan tool, clear the DTC.
  4. Ignition OFF, wait 30 seconds.
  5. Ignition ON, operate the vehicle within the Conditions for Running the DTC. If the DTC resets, replace the SGCM.

SGCM Coolant Pump Malfunction

  1. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
  2. Ignition ON, test for B+ between the B+ circuit terminal A and ground. If less than the specified value, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect a test lamp between the B+ circuit terminal A and the control circuit terminal B.
  4. Ignition ON, command the SGCM Coolant Pump Relay ON and OFF with a scan tool. The test lamp should turn On and OFF when commanded. If the test lamp does not turn ON and OFF when commanded, test the control circuit for an open/high resistance. If the circuit tests normal, replace the SGCM
  5. If all circuits test normal, test or replace the SGCM coolant pump

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator Control Module Coolant Pump Replacement»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#hybrid-cooling-system-repair-instructions)
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for SGCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The auxiliary power module (APM) 12-volt output voltage is used for a 12-volt line APM output voltage control and a 12-volt line voltage sensor rationality check. The starter/generator control module (SGCM) monitors the voltage sensor for the following

  1. To detect the failure of the APM 12-volt voltage sensor circuit below valid range.
  2. To detect the failure of the APM 12-volt voltage sensor circuit above valid range.

The engine is running.

P1A8D

Sensor output voltage less than 0.5 volt for 0.5 ms and the 12-volt power supply - 12-volt output voltage is greater than 5 volts for 0.5 ms.

P1A8E

Sensor output voltage greater than 4.2 volts (30.2 volts) for 0.5 ms and the 12-volt power supply - 12-volt output voltage is greater than 5 volts for 0.5 ms.

P1A8D, P1A8E

  1. Stop PWM (MGU shutdown).
  2. APM PWM off.

Clears 30 seconds after cycle wake up signal.

Possible internal sensor short to ground or open.

Possible internal sensor short to voltage or open.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

P1A8D, P1A8E

  1. With a scan tool, clear the DTC.
  2. Ignition OFF, wait 30 seconds.
  3. Ignition ON, operate the vehicle within the Conditions for Running the DTC. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The starter/generator control module (SGCM) monitors the 14-volt power module current sensor for an overcurrent condition to protect the MOSFET. In the hardware an overcurrent protection circuit is used to limit the current, and software monitors for an overcurrent reading in the sensor.

The engine is running.

The 12 volt charge is greater than 150 amps or less than -150 amps for 2 seconds

  1. In the software fault: Stop PWM (MGU shutdown) APM PWM off
  2. In the hardware fault: Stop PWM (MGU shutdown) APM PWM off Battery disconnection (disconnect SW on/off)

Hybrid system is disabled.

  1. In the software fault, APM current less than +/- 10 amps
  2. 12VOUT is greater than 7 volts.
  3. APMTEMP is less than 105°C (221°F) for 160 ms.
  4. Clears 30 seconds after cycle wake up signal.
  1. Battery cable short to ground
  2. Fuse/relay box electrical failures
  3. FET breakdown

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Inspect for any open fuses.
  2. Inspect all the 12-volt battery connections for short to ground as follows: At battery At SGCM At fuse block
  3. With a scan tool, clear the DTC.
  4. Ignition OFF, wait 30 seconds.
  5. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset. If the DTC resets, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming

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