Home ReviewsRefund
Home/Chevrolet/Malibu/Chevrolet Malibu VII (2008-2012)/Repair manual/Engine Control Systems/Hybrid Engine Controls - DTC p1a90 to DTC p1ab8
Contents Wiring diagrams Section: Engine Control Systems All sections

Hybrid Engine Controls - DTC p1a90 to DTC p1ab8 Chevrolet Malibu VII

Engine Control Systems ~3777 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 starter/generator control module (SGCM) monitors to detect the failure of the auxiliary power module (APM) temperature sensor by comparing the average of the 2 power inverter module (PIM) sensors and subtracting the module temperature to detect a faulty sensor.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

APM temperature sensor is greater than 55°C (131°F) for 2 seconds.

Action Taken When the DTC Sets

APM 50 percent maximum current output

Conditions for Clearing the DTC

APM temperature returns to normal range for 10 seconds.

Diagnostic Aids

Possible internal failure of the temperature sensor

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. 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-p1a90-to-dtc-p1ab8__circuitsystem-testing) under SGCM Coolant Pump Malfunction.
  3. Ignition ON, observe the scan tool SGCM temperature sensor parameters. If only the one temperature sensor reads high, replace the SGCM.

Circuit/System Testing

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

Repair Procedures

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) 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 APM temperature sensor for the following

  1. To detect if the internal APM temperature sensor is shorted low.
  2. To detect if the internal APM temperature sensor is shorted high.

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

The engine is running.

P1A91

FET temperature sensor signal for APM is less than 0.2 volts for 1 second.

P1A92

APM temperature sensor output voltage is greater than 4.6 volts (-14°C or 6.8°F) and APM temperature is greater than 55°C (131°F) for 1 second.

APM 50 percent maximum current output

Normal range for 10 seconds

Possible APM temperature sensor short to ground or open

Possible APM temperature 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

WARNINGTo help avoid personal injury, be careful when working in the vicinity of the battery energy control module. Internal components will still be live, 36V potential, even when the cover has been opened of removed.
  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 auxiliary power module (APM) On/Off, DC - DC direction is commanded On but converter is Off to check the status of the 14 volt power module. The SGCM also monitors to detect if the APM On when it is not commanded On causing a large current output. If a fault is detected, the appropriate DTC will set.

P1A93, P1A94

The engine is running.

P1A93

In normal charge mode, 12-volt output voltage - 12-volt command voltage is greater than 0.2 volt for 1 second.

P1A94

DC-DC direction is Off, but converter remains On and APM current is greater than +/-20 amps for 1 second.

  1. Stop PWM (MGU shutdown)
  2. APM PWM off
  3. Battery disconnection (disconnect SW on/off)

Clears 30 seconds after cycle wakeup signal.

  1. Electrical failure in SGCM, open circuit or open fuse
  2. FET breakdown

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

WARNINGTo help avoid personal injury, be careful when working in the vicinity of the battery energy control module. Internal components will still be live, 36V potential, even when the cover has been opened of removed.
  1. Gain access to the 12 volt 175 amp SGCM maxi fuse. Refer to «Generator Control Module Cover Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  2. Test for B+ at 175 amp maxi fuse. If less than specified value, test the supply voltage circuit for a short to ground or an open/high resistance.
  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.

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 auxiliary power module (APM) fault when the APM is commanded in the normal charge mode causing an over current condition. If a fault is detected, the appropriate DTC will set.

P1A95, P1A96

The engine is running.

P1A95

DC-DC direction indicates 42-14 volt direction, but converter stays in 14-42 volt direction and current is greater than 20 amps for 1 second.

P1A96

DC-DC direction indicates 14-42 volt direction, but converter stays in 42-14 volt direction and current is less than -20 amps for 1 second.

  1. Stop PWM (MGU shutdown)
  2. APM PWM off
  3. Battery disconnection (disconnect SW on/off)

Clears 30 seconds after cycle wakeup signal.

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

WARNINGTo help avoid personal injury, be careful when working in the vicinity of the battery energy control module. Internal components will still be live, 36V potential, even when the cover has been opened of removed.
  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 hybrid battery system voltage for a low and high condition to detect the failure of the 36-volt output voltage sensor that is below or above a valid range.

P1A97, P1A98

The engine is running.

P1A97

  1. Sensor signal is less than 0.2 volt for continuous 20 ms.
  2. Sensor signal is less than 0.2 volt for 20 ms and 36-volt battery voltage is greater than 5 volts for 20 ms.

P1A98

Sensor output voltage less than 4 volts and 36-volt battery voltage is greater than 5 volts for 20 ms.

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

Closes 30 seconds after cycle wake up signal.

Possible internal sensor shorted.

Possible internal sensor 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

WARNINGTo help avoid personal injury, be careful when working in the vicinity of the battery energy control module. Internal components will still be live, 36V potential, even when the cover has been opened of removed.
  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 power inverter module (PIM) temperature 1 sensor is used for overheat protection. The thermistor is located on the control board, near the phase W power MOSFET. The starter/generator control module (SGCM) monitors the inverter temperature sensor to detect the failure of the inverter temperature sensor using rationality of other temperature sensors to determine if it is out of range.

The engine is running.

Inverter temperature sensor is greater than 55°C (131°F) for 2 seconds.

50 percent maximum torque limit

Normal range for 10 seconds

Possible internal failure of temperature 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

WARNINGTo help avoid personal injury, be careful when working in the vicinity of the battery energy control module. Internal components will still be live, 36V potential, even when the cover has been opened of removed.
  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.

Generator Control Module Replacement 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 power inverter module (PIM) temperature 1 and 2 sensors are used for overheat protection. The thermistors are located on the control board, near the phase U or V power MOSFET. The starter/generator control module (SGCM) monitors the inverter temperature sensor for the following

  1. To detect if the inverter phase U or V temperature sensor is shorted.
  2. To detect if the inverter phase U or V temperature sensor is open.

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

P1A9C, P1A9D, P1AA0, P1AA1

The engine is running.

P1A9C, P1AA0

Sensor output voltage is less than 0.2 volt for 1 second.

P1A9D, P1AA1

Sensor output voltage is greater than 4.6 volts for 1 second.

50 percent maximum torque limit.

Normal range for 10 seconds.

Possible temperature sensor short to ground.

Possible temperature 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

WARNINGTo help avoid personal injury, be careful when working in the vicinity of the battery energy control module. Internal components will still be live, 36V potential, even when the cover has been opened of removed.
  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 power inverter module (PIM) temperature 1/2 sensor is used for overheat protection. The thermistor is located on the control board, near the phase U/V power MOSFET. The SGCM monitors the inverter temperature sensor for the following

  1. To detect if the inverter phase U/V temperature sensor is shorted low.
  2. To detect if the inverter phase U/V temperature sensor is shorted high.

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

P1A9E, P1AA2

The engine is running.

Temperature is greater than 175°C (347°F) for 20 ms.

Stop PWM (MGU shutdown)

Temperature is less than 150°C (302°F) for 2.5 seconds.

Possible 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. Inspect the 3 phase cable connections at the SGCM. Refer to «Generator Control Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  2. Verify that the 3 phase cables are torqued to within specifications. 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. 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 motor generator unit (MGU) field coil circuit to see if the field coil current is within tolerance. If a fault is detected, the appropriate DTC will set.

The engine is running.

P1AA8

Field coil current - command current is greater than 0.5 A for 1.0 second.

P1AB9

Sensor output voltage less than 1.8 volts (-2 A) for 20 ms.

P1ABA

Sensor output voltage greater than 4.1 volts (10 A) for 20 ms.

P1ABB

Field coil current is greater than 6 A for 20 ms.

Stop PWM (MGU shutdown)

The DTC will clear 30 seconds after the ignition is turned OFF and then turned back ON, enabling the module cycle wakeup signal.

Possible cable open or short to ground.

P1AB9, P1ABA

Possible open circuit or faulty cable connection.

Possible short circuit or faulty cable connection.

Schematic Reference

Connector End View Reference

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. Verify that the latest service software is installed.
  2. 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) .
  3. Using the appropriate test adapters, test for 5-100 ohms resistance between terminals 9 and 12. 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 less than 1 ohm between SGCM connector harness terminal 12 and the MGU X1 connector harness terminal A. If greater than the specified value, repair the open circuit.
  6. 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 value, repair the open circuit.
  7. Test for no continuity between SGCM connector harness terminal 9 and terminal 12. If greater than the specified value, repair the shorted circuits.
  8. Test for short between SGCM connector harness terminal 12 and ground. If greater than the specified value, repair the shorted circuit.
  9. 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) phase U/V/W current sensor is used for motor control and power inverter module (PIM) current sensor rationality check. The current sensor is soldered on the control board near the phase U/V/W bus bar. The SGCM monitors the current sensor for the following

P1AAE

To detect the electrical failure (short condition) of the phase current sensor

P1AAF

To detect a phase wire open condition

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

  1. The engine is running.
  2. Main relay is closed.

Current is less than or greater than 200A for 20 ms.

Current output is greater than 200A for 200 ms.

  1. Stop pulse width modulation (PWM) (motor generator unit (MGU) shutdown)
  2. Auxiliary power module (APM) PWM OFF
  3. Battery disconnection (disconnect SW on/off)

Stop PWM (MGU shutdown)

Sum of 3 phase current returns to normal.

Current amp output returns to normal.

  1. Possible short circuit
  2. Possible internal failure at current sensor
  1. Possible 3- phase cable open
  2. Possible MGU winding 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, disable the hybrid system. Refer to «Hybrid Battery Service Disconnect/Connect»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#hybrid-energy-storage-system-repair-instructions) .
  2. Inspect for poor connections and any evidence of arching at the 3-phase cable connectors of the SGCM and the MGU.
  3. Disconnect the 3-phase cables from the SGCM. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  4. Test for infinite between each of the 3-phase cables. Cable U to V Cable U to W Cable V to W
  5. Test for infinite resistance between each of the 3-phase cables and ground. If the circuits test normal, replace the SGCM.
  6. Disconnect the 3-phase cables from the MGU. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  7. Test for less than 1 ohm on each of the 3-phase cables. If the circuits test normal, replace the MGU. If not within the specified value, replace the 3-phase cable assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator Control Module 3-Phase Cable Assembly Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  2. «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  3. «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 phase U/V/W current sensor to detect 3 phase overcurrent and to protect the MOSFET.

  1. Engine is running.
  2. Wake up signal is ON.

Over current signal set for 20 ms.

  1. Stop PWM (MGU shutdown)
  2. APM PWM OFF
  3. Battery disconnection (disconnect SW on/off)

Over current signal not valid

  1. Possible MGU winding short to other winding or short to case
  2. Possible FET breakdown or gate driver circuit fault

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)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the 3-phase cables from the SGCM. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
  2. Ignition OFF, test for infinite resistance between each of the 3-phase cables and ground. If not the specified value, test the appropriate 3-phase cable for a short to ground. If a short to ground is found, replace the 3-phase cables. If the cable tests normal, replace the MGU.
  3. If all circuits test normal, replace the SGCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator Control Module 3-Phase Cable Assembly Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  2. «Generator with Starter Replacement»(/chevrolet/malibu/vii-2008-2012/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
  3. «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) phase U/V/W current sensors are used for motor control and power inverter module (PIM) current sensor rationality check. The SGCM monitors the current sensor for the following

  1. To detect a failure of the U/V/W-phase current sensor circuit below valid range
  2. To detect a failure of the U/V/W-phase current sensor circuit above valid range

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

P1AB3, P1AB4, P1AB5, P1AB6, P1AB7, P1AB8

  1. Engine is running.
  2. Wakeup signal is ON.

P1AB3, P1AB5, P1AB7

Sensor output voltage at high side less than 0.5 volt for 0.5 ms.

P1AB4, P1AB6, P1AB8

Sensor output voltage at high side greater than 4.5 volts for 0.5 ms.

  1. Stop PWM (MGU shutdown)
  2. APM PWM OFF
  3. Battery disconnection (disconnect SW on/off)

P1AB3, P1AB4

U-phase current sensor circuit within valid range

P1AB5, P1AB6

V-phase current sensor circuit within valid range

P1AB7, P1AB8

W-phase current sensor circuit within valid range

Possible electrical failure of the current sensor with short to ground or open

Possible electrical failure of the current sensor with 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. 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

More articles — Engine