Hybrid Engine Controls - DTC P181C to DTC p2792 Cadillac Escalade GMT900

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Typical Scan Tool Data

Internal Mode Switch (IMS)

Circuit/System Description

The internal mode switch (IMS) assembly is a sliding contact switch attached to the control valve body within the transmission. The nine outputs from the switch indicate which position is selected by the transmission manual shaft. Four outputs (A, B, C, P), are range selection inputs to the transmission control module (TCM). Five outputs (R1, R2, D1, D2, S) are direction selection inputs to the hybrid powertrain control module (HPCM). The input voltage at the module is high when the switch is open and low when the switch is closed to ground.

Conditions for Running the DTC

1. The ignition is ON.
2. Ignition voltage is greater than 6.0 volts.

Conditions for Setting the DTC

The IMS Direction Signal state does not match for the selected gear for 3 seconds.

Action Taken When the DTC Sets

DTCs P181C, P181D, P181E, P181F, P183A, P183B, P183C, P183D, P183E, P184A and P184B are Type B DTCs.

Conditions for Clearing the DTC

DTCs P181C, P181D, P181E, P181F, P183A, P183B, P183C, P183D, P183E, P184A and P184B are Type B DTCs.

Diagnostic Aids

1. The direction IMS assembly can be damaged by electric current exceeding 25 mA. Test the IMS assembly for an open condition whenever a short to voltage condition is observed.
2. The direction IMS is a non-serviceable part of the manual shift shaft position switch.

Reference Information

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

1. DT-47825-10 Jumper Harness. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) .
2. DT-48493 Jumper Harness. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) .

Circuit/System Verification

Test for correct operation of the Direction IMS in every range selection. Refer to Typical Scan Tool Data.

1. If the IMS operation matches the logic table, the system is functioning normally.

Circuit/System Testing

1. Disconnect the transmission X176 24-way connector. Ignition ON. The scan tool Direction IMS parameter should display HIGH for the R1, R2, D1, D2 and S signal circuit displays. If a signal displays LOW, disconnect the PIM connector X1 and test the circuit for a short to ground. If the circuit tests normal, replace the PIM.
2. Install DT-48493 to the vehicle harness connector X176. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Verify that a test lamp illuminates between the direction IMS switch ground circuit and battery positive. If the test lamp does not illuminate, disconnect PIM connector X1 and test the ground circuit for an open, high resistance or short to voltage condition. If the circuit tests normal, replace the PIM.
3. Connect a 3-amp fused jumper wire between each Direction IMS signal circuit at DT-48493 and the ground circuit terminal. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . The scan tool parameter should display LOW for each signal circuit when grounded. If a scan tool parameter always displays HIGH, disconnect PIM connector X1 and test the circuit for an open, high resistance or short to voltage condition. If the circuit tests normal, replace the PIM.
4. Disconnect the transmission 16-way X1 connector. Install DT-47825-10 to the vehicle harness. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Connect a 3-amp fused jumper wire between the Starter signal circuit terminal and ground. The scan tool parameter should display LOW when the signal circuit is grounded. If the scan tool parameter always displays HIGH, disconnect PIM connector X1 and test the circuit for an open, high resistance or short to voltage condition. If the circuit tests normal, replace the PIM.
5. Disconnect the IMS connector at the switch. IMPORTANT: Connect one end of the DT-48493 to the transmission connector. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Use the other end as the terminal testing point. Test the direction signal circuits and the ground circuit between the IMS and the transmission 24-way X176 connector for a short to ground, open, high resistance or short to voltage condition. IMPORTANT: Connect one end of the DT-47825-10 to the transmission connector. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Use the other end as the terminal testing point. Test the Starter signal circuit between the IMS and the transmission 16-way X1 connector for a short to ground, open, high resistance or short to voltage condition. The TCM is a pass-through of the Starter signal circuit and should be tested as a typical circuit path. If the circuit, including the TCM, tests normal, replace the IMS switch.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the repair.

1. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for PIM or TCM replacement, setup, and programming.
2. «Manual Shift Shaft Position Switch Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle) .
3. «Transmission Control Wiring Harness Extension Harness Removal»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle) .

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Internal Mode Switch (IMS)

The internal mode switch (IMS) assembly is a sliding contact switch attached to the control valve body within the transmission. The nine outputs from the switch indicate which position is selected by the transmission manual shaft. Four outputs (A, B, C, P), are range selection inputs to the transmission control module (TCM). Five outputs (R1, R2, D1, D2, S) are direction selection inputs to the hybrid powertrain control module (HPCM). The input voltage at the module is high when the switch is open and low when the switch is closed to ground.

1. The ignition is ON
2. DTCs P181C-P181F, P1824, P182A-P182F, P183A-P183E, P1838, P1839, P184A, or P184B are not set.

The IMS Direction State does not match the IMS Range State.

DTC P183F is a Type A DTC.

DTC P183F is a Type A DTC.

1. The direction IMS assembly can be damaged by electric current exceeding 25 mA. Test the IMS assembly for an open condition whenever a short to voltage condition is observed.
2. The direction IMS is a non-serviceable part of the manual shift shaft position switch.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

1. DT-47825-10 Jumper Harness. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) .
2. DT-48493 Jumper Harness. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) .

1. Clear the DTC information.
2. Turn the ignition OFF for 1 minute.
3. Turn the ignition ON.
4. Test for correct operation of the direction and range IMS switch circuits in every gear selection. Hold the selector in each gear position for at least 2 seconds. Refer to Typical Scan Tool Data. If the Direction IMS operation does not match the logic table proceed with Circuit/System Testing. If the IMS A/B/C/P operation does not match the logic table proceed to «DTC P1824, P182A-P182F, P1838, or P1839»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-dtc-p0969-to-dtc-p02730p279d) .
5. Retest for DTC P183F If the DTC resets, program the PIM with the latest software version and recheck for DTCs. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

1. Disconnect the transmission X176 24-way connector. Ignition ON. The scan tool Direction IMS parameter should display HIGH for the R1, R2, D1, D2 and S signal circuit displays. If a signal displays LOW, disconnect the PIM connector X1 and test the circuit for a short to ground. If the circuit tests normal, replace the PIM.
2. Install DT-48493 to the vehicle harness connector X176. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Verify that a test lamp illuminates between the Direction IMS switch ground circuit and battery positive. If the test lamp does not illuminate, disconnect PIM connector X1 and test the ground circuit for an open, high resistance or short to voltage condition. If the circuit tests normal, replace the PIM.
3. Connect a 3-amp fused jumper wire between each Direction IMS signal circuit at DT-48493 and the ground circuit terminal. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . The scan tool parameter should display LOW for each signal circuit when grounded. If a scan tool parameter always displays HIGH, disconnect PIM connector X1 and test the circuit for an open, high resistance or short to voltage condition. If the circuit tests normal, replace the PIM.
4. Disconnect the transmission 16-way X175 connector. Install DT-47825-10 to the vehicle harness. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Connect a 3-amp fused jumper wire between the Starter signal circuit terminal and ground. The scan tool parameter should display LOW when the signal circuit is grounded. If the scan tool parameter always displays HIGH, disconnect PIM connector X1 and test the circuit for an open, high resistance or short to voltage condition. If the circuit tests normal, replace the PIM.
5. Disconnect the IMS connector at the switch. IMPORTANT: Connect one end of the DT-48493 to the transmission connector. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Use the other end as the terminal testing point. Test the direction signal circuits and the ground circuit between the IMS and the transmission 24-way X176 connector for a short to ground, open, high resistance or short to voltage condition. IMPORTANT: Connect one end of the DT-47825-10 to the transmission connector. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Use the other end as the terminal testing point. Test the Starter signal circuit between the IMS and the transmission 16-way X175 connector for a short to ground, open, high resistance or short to voltage condition. The TCM is a pass-through of the Starter signal circuit and should be tested as a typical circuit path. If the circuit, including the TCM, tests normal, replace the IMS switch.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for PIM or TCM replacement, setup, and programming.
2. «Manual Shift Shaft Position Switch Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle) .
3. «Transmission Control Wiring Harness Extension Harness Removal»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle) .

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This is an internal fault detection of the Power Inverter Module (PIM). This fault is handled inside the PIM and no external circuits are involved.

1. The control module runs the program to detect an internal fault when the key is ON.
2. Ignition voltage is 8-18V.

The control module has detected an internal malfunction.

1. DTCs P1A4F, P1A50, P1A51, P1A52, P1A53, P1A54, P1ADC and P1ADD are Type A DTCs.
2. The PIM commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTCs P1A4F, P1A50, P1A51, P1A52, P1A53, P1A54, P1ADC and P1ADD are Type A DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Clear the DTC information.
2. Ignition OFF for 1 minute.
3. Ignition ON.
4. Retest for DTCs P1A4F, P1A50, P1A51, P1A52, P1A53, P1A54, P1ADC and P1ADD.

Program the PIM with the latest software version and recheck for DTCs.

1. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory dc power control module (APM) converts the energy that flows between the high voltage, 300 volt, direct current (DC) to intermediate voltage, 42 volt, DC to support the electric power steering (EPS). The APM receives a 42 volt enable command from the hybrid powertrain control module (HPCM) over the high speed hybrid GMLAN communication circuit.

The APM continuously monitors the status of its 42 volt circuitry. It will do some diagnostics on this circuitry when the ignition key is first turned to RUN. Additional diagnostics are run while the APM is doing 42 volt conversions after receiving the 42 volt enable command.

1. Ignition voltage is 7-16 volts.
2. The APM runs a portion of the diagnostics for this DTC at Accessory/Ignition On.
3. The APM runs more diagnostics when the 42 volt output is commanded on.

1. An external condition has caused an APM 42 volt malfunction, OR
2. The APM has detected an internal malfunction.

1. DTC P1A88 is a Type C DTC.
2. The APM will shutdown 42 volt conversion.

DTC P1A88 is a Type C DTC.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. This DTC can set as a result of conditions external to the APM. Before attempting to diagnose this DTC, ensure the following conditions have not been encountered: High voltage contactor relays opening any time the APM is doing 42 volt conversion. The high voltage system is greater than 390 volts or less than 216 volts during 42 volt conversion. Extreme cold weather conditions may occasionally cause the high voltage system to be greater than 390 volts. The 12 volt circuit is less than 6.7 volts during 42 volt conversion. A short circuit condition on the 42 volt circuit which causes the APM to produce greater than 60 amps. If any of the above APM-external conditions have occurred, diagnose the conditions as applicable and clear the DTC Information. No further diagnosis of this DTC is required. If none of the above APM-external conditions have been encountered, continue with Circuit/System Verification.
2. Turn the ignition key to the RUN position. Ensure that the high voltage contactor relays close. Do not go to START. If the high voltage contactor relays do not close, diagnose the DTC or symptom that is preventing them from closing before attempting to diagnose this DTC.
3. Test for DTC P1A88. If the diagnostic is set as Last Test Failed/Current, replace the APM.
4. Start the engine.
5. Test for DTCs P1A89, P1A8A and P1A8C. If any of the above diagnostics are set, diagnose those first.
6. After the engine has started, retest for DTC P1A88. If the diagnostic is set as Last Test Failed/Current, proceed to Circuit/System Testing. If the diagnostic is set as Last Test Passed, the external condition that set this DTC is no longer present. Clear the DTC Information. No further diagnosis of this DTC is required.

1. Turn the ignition key to the OFF position.
2. Disconnect the 42 volt X2 harness connector at the APM.
3. Turn the ignition key to ON. Do not go to START.
4. Use the scan tool APM Intermediate Voltage Control under the APM special functions list to turn on the 42 volt circuit. If the APM Intermediate Voltage is not between 40 and 44 volts, replace the APM. If the APM Intermediate Voltage is between 40 and 44 volts, the problem is not in the APM. This DTC can set for the following external reasons

1. High voltage contactor relays opening any time the APM is doing 42 volt conversion.
2. The high voltage system is greater than 390 volts or less than 216 volts during 42 volt conversion. Extreme cold weather conditions may occasionally cause the high voltage system to be greater than 390 volts.
3. The 12 volt circuit is less than 6.7 volts during 42 volt conversion.
4. A short circuit condition on the 42 volt circuit which causes the APM to produce greater than 60 amps.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The Accessory Power Module (APM) supplies the energy that flows between the high voltage, 300 volt, direct current (DC) and intermediate voltage, 42 volt, DC to support the Electric Power Steering (EPS). The APM receives a 42 volt enable command from the Hybrid Powertrain Control Module (HPCM) over the high speed hybrid GMLAN communication circuit. 42 volt APM functions will run only when the 42 volt APM enable is active on the high speed hybrid GMLAN communication circuit.

APM 42 volt output commanded on.

42 volt circuit below 21 volts during operation.

1. DTC P1A89 is a Type C DTC.
2. The APM will shutdown 42 volt conversions.

DTC P1A89 is a Type C DTC.

1. DTC C0895 03 EPS Voltage Below Threshold may be set.
2. DTC C0895 12 EPS Voltage Below Minimum Threshold may also be set.
3. The 42 volt circuit is only used by the EPS. The APM can apply 42 volts on the connector without being connected to the EPS.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Start the engine.
2. Using the scan tool, observe the 42V Circuit Voltage parameter on the APM data list. If the voltage is less than 40 volts, proceed to Circuit/System Testing.
3. Rotate the steering wheel back and forth while stationary. If the voltage is less than 40 volts, the EPS is drawing excessive current. Replace the power steering motor.

1. Disconnect the 42 Volt harness connector at the APM.
2. Turn the ignition to ON.
3. Use the APM Intermediate Voltage Control on the scan tool to turn on the 42 volt circuit. If the voltage is greater than 40 volts, replace the power steering control module (PSCM). If the voltage is less than 40 volts, replace the APM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Power Steering Assist Motor Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/electronic-steering/#power-steering-system)
2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for APM or PSCM replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The Accessory Power Module (APM) supplies the energy that flows between the high voltage, 300 volt, direct current (DC) and intermediate voltage, 42 volt, DC to support the Electric Power Steering (EPS). The APM receives a 42 volt enable command from the Hybrid Powertrain Control Module (HPCM) over the high speed hybrid GMLAN communication circuit. 42 volt APM functions will run only when the 42 volt APM enable is active on the high speed hybrid GMLAN communication circuit.

APM 42 volt output commanded on.

APM 42 volt circuit above 50 volts for more than 3 seconds.

1. DTC P1A8A is a Type C DTC.
2. The APM will shutdown 42 volt conversions.

1. DTC P1A8A is a Type C DTC.
2. 42 volt circuit is below 48 volts.

1. DTC C0895 07 EPS Voltage Above Threshold may be set.
2. The APM Data List on the scan tool contains a parameter named 42V Circuit Maximum. If this parameter has a voltage that is greater than 50 volts, the protection circuits in the power steering control module (PSCM) have failed and as a result, this is not a fault condition in the APM.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Start the engine.
2. Using the scan tool, observe the 42V Circuit Voltage parameter on the APM data list. If the 42V Circuit Voltage parameter is greater than 48 volts, replace the APM. If the 42V Circuit Voltage parameter is less than 48 volts, replace the PSCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for APM or PSCM replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The Accessory Power Module (APM) controls the energy flowing between the high voltage, 300-volt, direct current (DC) and intermediate voltage, 42-volt, DC to support the Electric Power Steering (EPS). The APM receives a 42-volt enable command from the Hybrid Powertrain Control Module (HPCM) over the high speed hybrid GMLAN communication circuit. APM functions will run only when the APM Enable is active on the high speed hybrid GMLAN communication circuit.

Heat is generated in the 42-volt APM circuit solely through the demand for use of the EPS. The Engine Control Module (ECM) measures the temperature of the Power Electronics Cooling Loop and commands the flow of 2 electrical coolant pumps. The APM transfers heat in the 42-volt circuit to the APM Heat Plate which is then dissipated at the Power Electronics Front End Heat Exchanger.

Based on the severity of an overheat condition in the 42-volt circuit, the APM will make decisions ranging from notification of an over temperature condition to the EPS to completely shutting down the 42-volt power conversion.

APM 42-volt output commanded on.

P1A8B 00

42-volt circuit temperature is greater than 105°C (221°F).

P1A8B 11

42-volt circuit temperature is greater than 115°C (239°F).

P1A8C

42-volt circuit temperature is greater than 125°C (257°F).

P1A8B

1. DTC P1A8B is a Type C DTC.
2. The HPCM stores the DTC information in memory when the diagnostic runs and fails.

P1A8C

1. DTC P1A8C is a Type C DTCs.
2. The HPCM stores the DTC information in memory when the diagnostic runs and fails.
3. The APM will shut down 42-volt conversion.

P18AB

DTC P1A8B is a Type C DTC.

42-volt circuit temperature is less than 90°C (194°F).

42-volt circuit temperature is less than 100°C (212°F).

P1A8C

1. DTC P1A8C is a Type C DTC.
2. 42-volt circuit temperature is less than 110°C (230°F).

1. DTC C0561 76 may be set.
2. This DTC could be caused by a possible power electronics cooling system failure due to the following: Restricted radiator air flow or coolant fans inoperative Restricted power electronics coolant flow or contaminated coolant Inoperative power electronics cooling system water pump

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Inspect for DTC P0AF7.

1. If the DTC is set, refer to «DTC P0AF7»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-dtc-b008a-to-dtc-p0af7) .
2. If the DTC is not set, continue to Circuit/System Testing.

1. Place the vehicle in Park and start the engine.
2. Place the steering wheel in the centered position. Do not rotate the steering wheel.
3. Observe the 42V Circuit Current parameter in the APM data list on the scan tool. If the 42V Circuit Current parameter is greater than 0.5 amps with no steering input, replace the power steering control module (PSCM).
4. Rapidly rotate the steering wheel to the left and right while observing the 42V Circuit Current parameter. If the 42V Circuit Current parameter is greater than 40 amps, replace the PSCM. If the 42V Circuit Current parameter is less than 40 amps, replace the APM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for APM or PSCM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The crankshaft position (CKP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit and an output signal circuit. The CKP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The CKP sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the CKP sensor output depends on the velocity of the crankshaft. The CKP sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the CKP sensor. The ECM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The ECM also uses CKP sensor output information to determine the crankshaft relative position to the camshaft, to detect cylinder misfire, and to control the CMP actuator if equipped.

Motor Control Module (MCM) 1 is also connected to the CKP sensor signal and low reference circuits. The MCM uses the CKP sensor output information to determine engine crankshaft position to aid in smooth engine Auto-starts. The MCM does not need the CKP sensor signal in order for the engine to start and run.

P1AC6 and P1AC7

1. Drive motor generator 1 is rotating.
2. The DTC runs continuously when the above conditions are met.

P1AC6

The MCM detects no engine speed signal for 2 seconds.

P1AC7

The MCM detects an invalid engine speed signal for 3 seconds.

DTCs P1AC6 and P1AC7 are Type B DTCs.

DTCs P1AC6 and P1AC7 are Type B DTCs.

With an ECM DTC P0335 set, the engine will only crank for about 2 seconds.

Schematic Reference

1. «Hybrid Controls Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/body-electrical/#hybrid-engine-controls-wiring-schematics)
2. «Engine Controls Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-hybrid-hp2-60l-lz1-wiring-schematic-and-emission-hose-routing-diagrams)

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Inspect for ECM P0335 or ECM P0336. With the engine running, observe the hybrid powertrain control module (HPCM) Engine Speed parameter with a scan tool. The parameter should display the current engine speed, matching the tachometer and/or the ECM Engine Speed parameter.

1. If ECM DTCs P0335 or P0336 are set, diagnose them prior to diagnosing the HPCM DTC.
2. If the HPCM Engine Speed parameter displays a value other than the current engine speed, continue with Circuit/System Testing.

Attempt to crank and start the engine. Perform the appropriate diagnostic procedure as necessary.

Diagnosis if the Engine Does NOT Start

1. Ignition OFF, disconnect the CKP sensor connector.
2. Ignition ON, test for 4.8-5.2 volts on the CKP signal circuit, from the CKP connector terminal A and ground. If within the specified range, reconnect the CKP connector and perform ECM DTC P0335 diagnostic procedure.
3. Ignition OFF, disconnect PIM connector X1.
4. Ignition ON, test for 4.8-5.2 volts on the CKP signal circuit, from the CKP sensor connector terminal A and ground. If within the specified range, replace the drive motor generator power inverter control module (PIM).
5. Test the CKP signal circuit between CKP connector terminal A and PIM connector X1 terminal 26 for a short to ground if less than the specified value or a short to voltage if greater than the specified value. If the circuit tests normal, reconnect all connectors and perform ECM DTC P0335 diagnostic procedure.

Diagnosis if the Engine Starts

1. Ignition OFF, disconnect PIM connector X1 and the CKP sensor connector.
2. Test for less than 5 ohms on the CKP low reference circuit, from connector X1 terminal 35 and ground. If greater than the specified value, repair the low reference circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts on the CKP signal circuit, from the connector X1 terminal 26 and ground. If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the drive motor generator power inverter control module (PIM).

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for PIM replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module (PIM) contains two motor control modules (MCM) and a hybrid powertrain control module (HPCM). The HPCM and both MCMs share the PIM ignition voltage circuit, battery voltage circuits and chassis ground.

Ignition is ON

MCM ignition voltage is less than 7.7 V for 1 second.

DTCs P1ADE and P1AE0 are Type C DTCs.

DTCs P1ADE and P1AE0 are Type C DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Clear the DTC information.
2. Turn the ignition OFF for 1 minute.
3. Turn the ignition ON.
4. Retest for DTCs P1ADE and P1AE0.

Test for HPCM DTC P0562.

1. Perform HPCM P0562 diagnosis if set.
2. If HPCM P0562 is not set, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

HVIC Source Current - BECM

HVIC Return Current - BECM

HPCM HVIC Status - HPCM

BECM HVIC Status - HPCM

The high voltage interlock circuit (HVIC) is utilized to verify high voltage component integrity. HVIC is a circuit loop that passes through certain high voltage components. HVIC is used to determine if access to high voltage components is being attempted. The opening of these high voltage components causes HVIC to open. The battery energy control module (BECM) sources about 12 mA of current on the 5V HVIC loop. The BECM monitors both the HVIC source circuit current and the HVIC return circuit current in order to detect circuit faults. Both motor control modules (MCMs) monitor the circuit for current in order to detect an open condition. When the BECM and/or the MCMs sense conditions such as a loss of HVIC current, the high voltage contactor relays are commanded open by the hybrid powertrain control module (HPCM).

P1B05 and P1B06

1. Ignition voltage is 8-18 volts.
2. Wake up signal is active.
3. BECM is supplying current on HVIC circuit. This normally occurs when HV contactor relays are closed.

P1AE2, P1AE3 and P1AE4

1. Ignition voltage is 9-18 volts.
2. Wake up signal is active.
3. BECM is supplying current on HVIC circuit. This normally occurs when HV contactor relays are closed.

P1B05 and P1B06

1. The MCM does not detect HVIC current flow.
2. DTC P1B05 and P1B06 set within 1 second when the above condition is met.

P1AE2

1. The BECM detects HVIC source current is less than 5 mA and HVIC return current is less than 5 mA.
2. DTC P1AE2 sets within 1 second when the above condition is met.

P1AE3

1. The BECM detects HVIC source current is between 5-18 mA and HVIC return current is less than 5 mA.
2. DTC P1AE3 sets within 1 second when the above condition is met.

P1AE4

1. The BECM detects HVIC source current is less than 5 mA and HVIC return current is greater than 35 mA.
2. DTC P1AE4 sets within 1 second when the above condition is met.

1. DTCs P1B05, P1B06, P1AE2, P1AE3, P1AE4 are Type C DTCs.
2. The HPCM commands the BECM to open the high voltage contactor relays when vehicle speed is less than 5 km/h (3 mph) for 6 seconds.

DTCs P1B05, P1B06, P1AE2, P1AE3, P1AE4 are Type C DTCs.

1. Test for a fully engaged high voltage manual disconnect lever whenever an open HVIC condition is observed. The manual disconnect lever must be pressed down fully in order to engage the HVIC terminals.
2. The BECM HVIC source and HVIC return circuit current sensors may not measure actual circuit current with the same accuracy. The BECM HVIC Source parameter may indicate less current than the BECM HVIC Return parameter for this reason. Measuring actual HVIC current with a DMM may also not compare directly to the parameter display.
3. The HVIC detects removal of the following components: The drive motor generator control module sight shield The transmission 3 phase cable cover The high voltage manual disconnect lever The hybrid battery terminal extension cover assembly
4. The HVIC is also routed through several inline connectors.
5. With the ignition in the OFF position, the BECM will source the HVIC current for 5 minutes every time a vehicle door is opened.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Capture and then clear the DTC information.
2. Ignition OFF, wait 2 minutes.
3. Ignition ON, observe the HPCMs BECM HVIC Status and HPCM HVIC Status parameters. The parameters should both indicate a PASS condition.

P1B05 and P1B06 without P1AE2, P1AE3 or P1AE4

1. Ignition OFF, wait 2 minutes.
2. Disconnect PIM connector X1.
3. Ignition ON, observe the BECM HVIC Current Source parameter. If the HVIC Current Source parameter indicates current less than 5 mA, replace the PIM. If the HVIC Current Source parameter indicates current between 5-18 mA test for the HVIC Source and HVIC Return circuits shorted together between PIM connector X1 and X350. WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. IMPORTANT: Removal of the HV manual disconnect lever also opens the HVIC source circuit between X350 and BECM connector X1. If the circuit tests normal, perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure and test for the HVIC Source and HVIC Return circuits shorted together between X350 and BECM connector X1. If the circuit tests normal, replace the BECM.

P1B05 and P1B06 with P1AE2

1. Ignition OFF, wait 2 minutes.
2. Disconnect PIM connector X1.
3. Install a 3 A fused jumper wire between the HVIC return circuit terminal 1 and the HVIC source circuit terminal 23.
4. Ignition ON, observe the BECM HVIC Source Current parameter. If the HVIC Source Current parameter indicates current between 5-18 mA, test for proper PIM connector X1 terminal contact at terminal 1 and terminal 23. If the terminal contact tests normal, replace the PIM.
5. Remove the PIM terminal 1 to terminal 23 fused jumper wire.
6. Test for 5-18 mA with a DMM between the HVIC Source circuit terminal 23 and ground. If within the specified range, test the HVIC Return circuit for an open between PIM connector X1 and X350. WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. If the circuit tests normal, perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure and test the HVIC Return circuit for an open between X350 and BECM connector X1. If the circuit tests normal, replace the BECM. If less than the specified range, test the HVIC Source circuit for an open between PIM connector X1 and X350. WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. IMPORTANT: Removal of the HV manual disconnect lever also opens the HVIC source circuit between X350 and BECM connector X1. If the circuit tests normal, perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure and test the HVIC Source circuit for an open between X350 and BECM connector X1. If the circuit tests normal, replace the BECM.

P1AE3 with or without P1B05 and P1B06

1. Ignition OFF, wait 2 minutes.
2. Disconnect PIM connector X1.
3. Ignition ON, observe the BECM HVIC Source Current parameter. The parameter should display less than 5 mA. If the HVIC Source Current parameter indicates current between 5-18 mA test the HVIC Source circuit for a short to ground between PIM connector X1 and X350. WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. IMPORTANT: Removal of the HV manual disconnect lever also opens the HVIC source circuit between X350 and BECM connector X1. If the circuit tests normal, perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure and test the HVIC Source circuit for a short to ground between X350 and BECM connector X1. If the circuit tests normal, replace the BECM.
4. Install a 3A fused jumper wire between the HVIC return circuit terminal 1 and the HVIC Source circuit terminal 23.
5. Observe the BECM HVIC Source Current and HVIC Return Current parameters with the scan tool. If both HVIC Source Current and HVIC Return Current parameters indicate current between 5-18 mA, replace the PIM. If only the HVIC Source Current parameter indicates current between 5-18 mA test the HVIC Return circuit for a short to ground between PIM connector X1 and X350. WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. If the circuit tests normal, perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure and test the HVIC Return circuit for a short to ground between X350 and BECM connector X1. If the circuit tests normal, replace the BECM.

P1AE4 with or without P1B05 and P1B06

1. Ignition OFF, wait 2 minutes.
2. Disconnect PIM connector X1.
3. Ignition ON, test for less than 35 mA with a DMM between the HVIC Source circuit terminal 23 and ground. If more than the specified range, test the HVIC Source circuit for a short to voltage between PIM connector X1 and X350. WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. IMPORTANT: Removal of the HV manual disconnect lever also opens the HVIC source circuit between X350 and BECM connector X1. If the circuit tests normal, perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure and test the HVIC Source circuit for a short to voltage between X350 and BECM connector X1. If the circuit tests normal, replace the BECM.
4. Ignition ON, test for less than 35 mA with a DMM between the HVIC Return circuit terminal 1 and ground. If more than the specified range, test the HVIC Return circuit for a short to voltage between PIM connector X1 and X350. WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. If the circuit tests normal, perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure and test the HVIC Return circuit for a short to voltage between X350 and BECM connector X1. If the circuit tests normal, replace the BECM.
5. If all circuits test normal, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for PIM or BECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module (PIM) contains two motor control modules (MCM). Each MCM monitors its internal high voltage sensor for correct operation.

1. Ignition is ON.
2. Ignition voltage is 8-18V.
3. The high voltage contactor relays are closed.

P1AE8 and P1AEA

The motor control module (MCM) detects high voltage sensor voltage less than 0V.

P1AE9 and P1AEB

The motor control module (MCM) detects high voltage sensor voltage greater than 564V.

1. DTCs P1AE8, P1AE9, P1AEA and P1AEB are Type B DTCs.
2. The hybrid powertrain control module (HPCM) commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTCs P1AE8, P1AE9, P1AEA and P1AEB are Type B DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Clear the DTC information.
2. Ignition OFF for 1 minute.
3. Ignition ON.
4. Retest for DTCs P1AE8, P1AE9, P1AEA and P1AEB.

Ignition ON, retest for DTCs P1AE8, P1AE9, P1AEA and P1AEB.

1. If the DTC resets, program the PIM with the latest software version and recheck for DTCs. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter control module (PIM) contains two motor control modules (MCMs). Each MCM measures hybrid battery high voltage with several internal sensors. The battery energy control module (BECM) also monitors high voltage with several internal sensors. The BECM high voltage measurement is broadcast over GMLAN.

P1AEC and P1AED

The MCM compares the values in order to verify the hybrid battery high voltage measurement is accurate.

P1AEE and P1AEF

The MCM monitors for high voltage that is greater than the system allows during normal operation.

1. The high voltage contactor relays are closed.
2. Ignition voltage is 8-18V.

The MCM hybrid battery high voltage sensor measurements are greater than 30V apart.

The MCM hybrid battery high voltage sensor monitors greater than 475V.

1. DTCs P1AEC, P1AED, P1AEE and P1AEF are Type A DTCs.
2. The PIM commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTCs P1AEC, P1AED, P1AEE and P1AEF are Type A DTCs.

DTCs P1AEC and P1AED compare the MCM measured high voltage to the BECM measurement of high voltage which is broadcast over GMLAN. Conditions that cause the BECM to improperly measure high voltage or a failure of the BECM to transmit its high voltage value may set this DTC.

DTCs P1AEE and P1AEF indicate that the high voltage contactor relays may have opened while large current flow was present. Conditions such as loss of BECM power or ground or removal of the high voltage manual disconnect while the vehicle was driving create a voltage surge that may set this DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Inspect for DTCs P0ABB, P0ABC, P0ABD, loss of communication with the BECM U-code DTCs, or any other concern that would indicate high voltage to the PIM was interrupted while high current was present. If the specified DTCs are set, or high voltage interruption is suspected, diagnose them first. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Clear the DTC information.
3. Ignition OFF for 1 minute.
4. Ignition ON.
5. Retest for DTCs P1AEC, P1AED, P1AEE and P1AEF.

1. If the DTC resets, program the PIM with the latest software version and recheck for DTCs. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter control module (PIM) contains two motor control modules (MCMs). Each MCM measures hybrid battery high voltage (HV) with several internal sensors. The MCMs test for loss of isolation (LOI) between either the HV positive circuit or HV negative circuit and vehicle chassis. The MCMs test for isolation when the HV contactor relays are closed. The battery energy control module (BECM) only tests the hybrid battery assembly for HV loss of isolation when the HV contactor relays are open.

MCM LOI is detected through the use of two high-impedance resistors and voltage measuring circuitry. The two resistors are connected in series between the HV positive and HV negative circuits. The center connection of the two resistors is also connected to vehicle chassis. The MCM then measures the voltage drop across one of the resistors. Without a loss of isolation, the MCM should measure about half of the high voltage potential. This is referred to as mid-pack voltage. The Mid-pack voltage value is then doubled by the software and displayed on a scan tool as Motor 1 Isolation Voltage or Motor 2 Isolation Voltage. When a loss of isolation is present, the motor isolation voltage display will indicate voltage that is more or less than actual hybrid battery high voltage.

1. The high voltage contactor relays are closed.
2. High voltage is greater than 50 volts.
3. Ignition voltage is 8-18 volts.
4. DTCs P1AEE, P1AF4, and P1AF5 are not set.

The ratio between Mid-Pack Voltage and hybrid battery high voltage is less than 0.27 or greater than 1.80.

OR

1. Mid-Pack Voltage is less than 35V or greater than 975V.
2. Either above condition exists for 5 seconds.

DTCs P1AF0 and P1AF2 are Type C DTCs.

DTCs P1AF0 and P1AF2 are Type C DTCs.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

1. EL-48458 Pre-Charge Test Tool. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) .
2. EL-48569 Terminal Covers

1. Inspect for DTC P1AE7. If the DTC is set, the loss of isolation has occurred within the drive motor generator battery. Diagnose this concern first. Refer to «DTC P1AE6 or P1AE7»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system) .
2. Inspect for DTCs P0A78, P0A79, P0BFD, P0BFE, P0C01, or P0C04. If any of the DTCs are set, the loss of isolation has occurred within the 3-phase components. Diagnose this concern first. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
3. Clear the DTC information.
4. Turn the ignition OFF for 1 minute.
5. Turn the ignition ON.
6. Operate the vehicle within the Conditions for Running the DTC.
7. Retest for DTCs P1AF0 and P1AF2.

1. Inspect for DTC P1AE7. If the DTC is set, the loss of isolation has occurred within the drive motor generator battery. Refer to «DTC P1AE6 or P1AE7»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system) .
2. Inspect for DTCs P0A78, P0A79, P0BFD, P0BFE, P0C01, or P0C04. If any of the DTCs are set, the loss of isolation has occurred within the 3-phase components. Diagnose this concern first. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
3. Place the vehicle in the following condition: Ignition OFF for at least 2 minutes Hood Closed Transmission in Park
4. Turn the ignition ON with the engine OFF. Observe and record the scan tool HPCM 300V Circuit Voltage parameter. High voltage should be enabled and Hybrid Battery voltage observed. Compare the HPCM 300V Circuit Voltage parameter value to the MCM 1 Isolation Voltage display and MCM 2 Isolation Voltage display. With no loss of isolation currently present, these values should all be within 20V of each other. If ONLY ONE MCM Isolation Voltage value is not within the indicated range, replace the PIM. If BOTH MCM Isolation Voltage values are not within the indicated range, continue to the next step. If BOTH MCM Isolation Voltage values are within the indicated range, a loss of isolation condition is not currently present. Proceed to Drive Motor Generator Phase Testing below.
5. Perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator control module cable connections.
6. Remove the air conditioning control module (ACCM) high voltage cable connector from the drive motor generator power inverter module (PIM). Protect the terminal ends immediately with the EL-48569 terminal covers and UL® Listed or equivalent insulation tape rated at a minimum of 600 volts.
7. Temporarily install the PIM high voltage distribution cover.
8. Install the drive motor generator control module sight shield.
9. Install the high voltage manual disconnect lever.
10. Connect the 12 volt battery. Refer to «Battery Negative Cable Disconnection and Connection»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-electrical-system-hp2) .
11. Place the vehicle in the following condition: Hood Closed Transmission in Park
12. Turn the ignition ON with the engine OFF. Observe and record the scan tool HPCM 300V Circuit Voltage parameter. High voltage should be enabled and Hybrid Battery voltage observed. Compare the HPCM 300V Circuit Voltage parameter value to the MCM 1 Isolation Voltage display. With no loss of isolation currently present, these values should be within 20V of each other. If the values are not within the indicated range, continue to the next step. If the values are within the indicated range, replace the ACCM.
13. Perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator control module cable connections.
14. Remove the high voltage Battery Positive and Negative Cable Assembly (300V) connector from the drive motor generator power inverter module (PIM). Remove and retain the cable mounting block O-ring. Re-install the O-ring after testing is complete.
15. Referring to «High Voltage System Diagnosis (EL-48458)»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-symptom-troubleshooting-diagnosis) for Installation Procedure, set-up, and usage instructions, connect the EL-48458 to the Battery Positive and Negative Cable Assembly (300V) and the PIM connector X1. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Turn the high voltage contactor relay to the Closed position. The High Voltage Circuit Greater than 60V When Lit lamp should be illuminated. If the Greater than 60V When Lit lamp does not illuminate inspect «Drive Motor Generator Battery Control Module Scan Tool Information»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information__drive-motor-generator-battery-control-module) for the contactor open reasons such as an open high voltage interlock circuit (HVIC) condition. Repair the reason for the open contactor condition, turn the ignition OFF and repeat this step.
16. Activate the BECM 300V Isolation Test output control with the scan tool. Observe the 300V Isolation Test Status scan tool parameter. The Isolation Test should complete within 1 minute. If the 300V Isolation Test Status parameter indicates a Passed condition, replace the PIM and Accessory DC Power Control Module (APM). If the 300V Isolation Test Status parameter indicates a Failed condition, continue to the next step.
17. Verify high voltage is not present before disconnecting the EL-48458 from the vehicle. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Refer to «High Voltage System Diagnosis (EL-48458)»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-symptom-troubleshooting-diagnosis) for Removal Procedure.
18. Perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator battery.
19. Remove the high voltage Battery Positive and Negative Cable Assembly (300V) connector from the drive motor generator battery assembly. Protect the terminal ends immediately with the EL-48569 terminal covers and UL® Listed or equivalent insulation tape rated at a minimum of 600 volts.
20. Referring to «High Voltage System Diagnosis (EL-48458)»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-symptom-troubleshooting-diagnosis) for usage and set-up instructions, connect the EL-48458 to the hybrid battery high voltage terminals and PIM connector X1 with the EL-48458 extension harnesses. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) . Turn the high voltage contactor relay to the Closed position. The High Voltage Circuit Greater Than 60V When Lit lamp should be illuminated. If the Greater than 60V When Lit lamp does not illuminate inspect «Drive Motor Generator Battery Control Module Scan Tool Information»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information__drive-motor-generator-battery-control-module) for the contactor open reasons such as an open high voltage interlock circuit (HVIC) condition. Repair the reason for the open contactor condition, turn the ignition OFF and repeat this step.
21. Activate the BECM 300V Isolation Test output control with the scan tool. Observe the 300V Isolation Test Status scan tool parameter. The Isolation Test should complete within 1 minute. If the 300V Isolation Test Status indicates a Passed condition, replace the Battery Positive and Negative Cable Assembly (300V). If the 300V Isolation Test Status indicates a Failed condition, the loss of isolation has occurred within the hybrid battery between the switched side of the high voltage contactors and the hybrid battery high voltage terminal assembly. Replace or repair the Hybrid Battery assembly as applicable.

Drive Motor Generator Phase Testing

1. Perform the «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator control module cable connections.
2. Remove the 3-phase cable assembly from the PIM distribution box. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
3. Test the resistance to ground for each phase of both drive motor generators by measuring between the following points with a DMM. You should measure infinite resistance. Phase U terminal and chassis ground Phase V terminal and chassis ground Phase W terminal and chassis ground If infinite resistance is measured, a measurable loss of isolation is not currently present. Reassemble the vehicle and retest for DTCs. If less than the specified value, continue with Circuit/System Testing.
4. Remove the 3-phase cable assembly from the transmission. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) . Ensure the terminals are not contacting chassis ground.
5. Retest the resistance to ground for each phase of the 3-phase cable. Measure between the following points with a DMM. You should measure infinite resistance. Phase U terminal and shield ground Phase V terminal and shield ground Phase W terminal and shield ground If infinite resistance is measured, replace the applicable drive motor generator. If less than the specified value, replace the generator control module 3-phase cable assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for PIM and APM replacement, setup, and programming.
2. «Drive Motor Battery Positive and Negative Cable Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system)
3. «Air Conditioning Compressor Replacement (HP2)»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Air Conditioning Compressor Replacement (LY2, LY5, LH6, L76, L92 and LMG)»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
4. «Generator Control Module 3-Phase Cable Assembly Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
5. «Drive Motor with Generator Assembly Removal - 1st Position»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
6. «Drive Motor with Generator Assembly Removal - 2nd Position»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter control module (PIM) contains two motor control modules (MCMs). Each MCM measures hybrid battery high voltage (HV) with several internal sensors. The MCMs test for loss of isolation (LOI) between either the HV positive circuit or HV negative circuit and vehicle chassis. The MCMs test for isolation when the HV contactor relays are closed. The battery energy control module (BECM) only tests the hybrid battery assembly for HV loss of isolation when the HV contactor relays are open.

MCM LOI is detected through the use of two high-impedance resistors and voltage measuring circuitry. The two resistors are connected in series between the HV positive and HV negative circuits. The center connection of the two resistors is also connected to vehicle chassis. The MCM then measures the voltage drop across one of the resistors. Without a loss of isolation, the MCM should measure about half of the high voltage potential. This is referred to as mid-pack voltage. The Mid-pack voltage value is then doubled by the software and displayed on a scan tool as Motor 1 Isolation Voltage or Motor 2 Isolation Voltage. When a loss of isolation is present, the motor isolation voltage display will indicate voltage that is more or less than actual hybrid battery high voltage. The MCM monitors the LOI voltage measuring circuitry for correct operation.

1. The control module runs the program to detect an internal fault when the key is ON.
2. Ignition voltage is 8-18 volts.

P1AF4 and P1AF6

The motor control module (MCM) detects isolation sensor voltage less than 0V.

P1AF5 and P1AF7

The MCM detects isolation sensor voltage greater than 564V.

1. DTCs P1AF4, P1AF5, P1AF6 and P1AF7 are Type B DTCs.
2. The hybrid powertrain control module (HPCM) commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTCs P1AF4, P1AF5, P1AF6 and P1AF7 are Type B DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Inspect for DTC P1AE7. If the DTC has set, a loss of isolation condition within the hybrid battery has caused this DTC to set. Refer to «DTC P1AE6 or P1AE7»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system) .
2. Clear the DTC information.
3. Turn the ignition OFF for 1 minute.
4. Turn the ignition ON.
5. Retest for DTCs P1AF4, P1AF5, P1AF6 and P1AF7.

1. Inspect for DTC P1AE7. If the DTC has set, a loss of isolation condition within the hybrid battery has caused this DTC to set. Refer to «DTC P1AE6 or P1AE7»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system) .
2. Ignition ON, retest for DTCs P1AF4, P1AF5, P1AF6 and P1AF7. If the DTC resets, program the PIM with the latest software version and recheck for DTCs. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter control module (PIM) contains two motor control modules (MCMs) and the hybrid powertrain control module (HPCM). Each MCM operates its respective drive motor generator based upon HPCM commands. Each MCM controls the speed, direction and output torque of its respective drive motor generator through the sequencing actuation of high current switching transistors called insulated gate bipolar transistors (IGBTs). Each drive motor generator operates utilizing 3 phase alternating current (ac) electricity. Each IGBT operates a single phase of the drive motor generator. Each phase is individually identified as U, V and W. Each MCM monitors the current of each phase in order to detect PIM overcurrent conditions.

At ignition ON, each MCM tests the integrity of the drive motor phase circuits by sequencing the IGBTs between open and shorted states while simultaneously injecting a large amount of current into the phase circuits. The individual phase current sensors should all indicate similar current flow and the current flow should increase and decrease at known rates based upon the inductance of the drive motor.

1. The ignition is transitioned to ON.
2. Ignition voltage is 8-18 volts.
3. High voltage has been enabled.

The control module has detected a phase current that indicates an open or shorted 3 phase circuit condition exists.

1. DTCs P1AF8 and P1AFE are Type A DTCs.
2. The HPCM commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTCs P1AF8 and P1AFE are Type A DTCs.

1. An intermittent loss of battery power to the drive motor generator power inverter control module (PIM) may set this DTC.
2. An open or shorted 3 phase circuit, prior to ignition ON, may set this DTC.

Schematic Reference

Hybrid Controls Schematics

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Clear the DTC information.
2. Turn the ignition OFF for 1 minute.
3. Turn the ignition ON.
4. Retest for DTC P1AF8 or P1AFE.

1. Verify that DTCs P0C01, P0C04, P0BFD, or P0BFE is not set. If the DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Disable the high voltage for servicing at the drive motor generator control module assembly cable connections. Refer to «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) .
3. Inspect for damaged 3 phase cables between the PIM and the transmission. If damage is observed, replace the 3 phase cables.
4. Inspect the 3 phase cable terminal fasteners for the proper torque and for arc-flash damage. If any fasteners were loose and no arc flash damage is present, torque the fasteners and re-assemble the vehicle. Retest for the DTC. If any fasteners were loose and arc flash damage is present, replace the PIM and the 3 phase cable assembly.
5. Remove the 3 phase cable assembly from the PIM distribution box. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
6. Test the resistance of each phase by measuring between the following circuits with a DMM. Phase U and phase V Phase U and phase W If you measure 0.5 ohms or less, continue with Circuit/System Testing. If you measure more than 0.5 ohms, proceed to Open Phase Testing Procedure below.
7. Test the resistance to ground for each phase of the applicable drive motor generator by measuring between the following points with a DMM. Phase U terminal and chassis ground Phase V terminal and chassis ground Phase W terminal and chassis ground If infinite resistance is measured, replace the 3-phase cable assembly and the drive motor generator assembly that corresponds to the set DTC and retest for the DTC. If the DTC resets replace the PIM. If less than infinite is measured, continue with Circuit/System Testing.
8. Remove the 3-phase cable assembly from the transmission. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) . Ensure the terminals are not contacting chassis ground.
9. Retest the resistance to ground for each phase of the 3-phase cable. Measure between the following points with a DMM. Phase U terminal and shield ground Phase V terminal and shield ground Phase W terminal and shield ground If infinite resistance is measured, replace the applicable drive motor generator. If less than infinite is measured, replace the generator control module 3-phase cable assembly.

Open Phase Testing Procedure

1. Remove the 3 phase cable assembly cover from the transmission and inspect the 3 phase cable terminal fasteners for the proper torque and for arc-flash damage. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) . If any fasteners were loose and no arc flash damage is present, torque the fasteners and re-assemble the vehicle. Retest for the DTC. If any fasteners were loose and arc flash damage is present, replace the applicable drive motor generator assembly and the 3 phase cable assembly.
2. Disconnect the 3 phase cable assembly from the transmission. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions) .
3. Test each cable for continuity from the PIM connection terminal to the transmission connection terminal. If you measure greater than 0.5 ohms, replace the 3 phase cable assembly. If you measure 0.5 ohms or less, replace the applicable drive motor generator assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for PIM replacement, setup, and programming
2. «Generator Control Module 3-Phase Cable Assembly Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-repair-instructions)
3. «Drive Motor with Generator Assembly Removal - 1st Position»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle) or «Drive Motor with Generator Assembly Removal - 2nd Position»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module (HPCM). The HPCM and each Motor Control Module (MCM) utilize a programmable logic device (PLD) to perform certain input and output functions. MCM 1 programs the PLD with software at every ignition ON event. MCM 1 verifies that the PLD is programmed successfully.

1. The control module runs the program to detect an internal fault when the key is ON.
2. Ignition voltage is 8-18V.

The control module has detected an internal PLD malfunction.

1. DTC P1AFA is a Type A DTC.
2. The HPCM commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTC P1AFA is a Type A DTC.

An intermittent loss of battery power to the drive motor generator power inverter module assembly (PIM) may set this DTC.

Connector End View Reference

Component Connector End Views

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Clear the DTC information.
2. Ignition OFF for 1 minute.
3. Ignition ON.
4. Retest for DTC P1AFA.

1. Ignition OFF.
2. Wait 2 minutes.
3. Disconnect PIM connector X1.
4. Wait 2 minutes.
5. Reconnect the PIM connector X1.
6. Ignition ON, retest for DTC P1AFA. If the DTC resets, program the PIM with the latest software version and recheck for DTCs. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module (HPCM). The HPCM and each Motor Control Module (MCM) utilize a programmable logic device (PLD) to perform certain input and output functions. MCM 1 programs the PLD with software at every ignition ON event. MCM 1 and 2 verify that the PLD is programmed successfully.

1. The ignition is in RUN or CRANK.
2. Ignition voltage is 8-18V.

The control module has detected an internal PLD malfunction.

1. DTCs P1AFB and P1B01 are Type A DTCs.
2. The HPCM commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTCs P1AFB and P1B01 are Type A DTCs.

An intermittent loss of battery voltage to the drive motor generator power inverter module assembly (PIM) may set this DTC.

Connector End View Reference

Component Connector End Views

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Clear the DTC information.
2. Ignition OFF for 1 minute.
3. Ignition ON.
4. Retest for DTC P1AFB or P1B01.

1. Ignition OFF.
2. Wait 2 minutes.
3. Disconnect PIM connector X1.
4. Ignition OFF.
5. Wait 2 minutes.
6. Reconnect PIM connector X1.
7. Ignition ON, retest for DTC P1AFB or P1B01. If the DTC resets, program the PIM with the latest software version and recheck for DTCs. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This is an internal fault detection of the drive motor generator power inverter module (PIM) assembly. This fault is handled inside the PIM and no external circuits are involved. The PIM contains two motor control modules (MCMs) and the hybrid powertrain control module (HPCM). In addition to GM LAN, these modules share dedicated, internal PIM communications circuits.

1. The control module runs the program to detect an internal fault when the key is ON.
2. Ignition voltage is 8-18V.

P1AFC

MCM 1 detects a loss of SPI bus communication with the HPCM.

P1AFD

MCM 1 detects a loss of SCI bus communication with MCM 2 for 2 seconds.

P1B02

MCM 2 detects a loss of SPI bus communication with the HPCM.

1. DTCs P1AFC and P1B02 are Type A DTCs.
2. DTC P1AFD is a Type B DTC.
3. The HPCM commands the battery energy control module (BECM) to open the high voltage contactor relays.

1. DTCs P1AFC and P1B02 are Type A DTCs.
2. DTC P1AFD is a Type B DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Clear the DTC information.
2. Ignition OFF for 1 minute.
3. Ignition ON.
4. Retest for DTCs P1AFC, P1AFD and P1B02.

Ignition ON, retest for DTCs P1AFC, P1AFD and P1B02.

1. If the DTC resets, program the PIM with the latest software version and recheck for DTCs. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Drive Motor Generator 1

Drive Motor Generator 2

The drive motor position sensor is monitored by the motor control module (MCM). The MCM monitors the angular position, speed and direction of the drive motor generator based upon the signals of the resolver-type position sensor. The position sensor, or resolver, contains a drive coil, two driven coils and an irregular shaped metallic rotor. The metallic rotor is mechanically attached to the shaft of the drive motor generator. At ignition ON, the MCM outputs a 7 volt ac, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field surrounding the two driven coils and the irregular shaped rotor. The MCM then monitors the two driven coil circuits for a return signal. The position of the irregular shaped metallic rotor causes the magnetically-induced return signals of the driven coils to vary in size and shape. A comparison of the two driven coil signals allows the MCM to determine the exact position, speed and direction of the drive motor generator.

The ignition is ON.

The MCM cannot track the motor position.

1. DTCs P1B03 and P1B04 are Type A DTCs.
2. The hybrid powertrain control module (HPCM) commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTCs P1B03 and P1B04 are Type A DTCs.

1. The drive motor generator position sensor circuits operate at very low current. Extreme care must be taken when probing terminals and manipulating harnesses.
2. The sensor circuit loops are twisted pair with each pair covered in a foil shield. The shield circuits outside of the transmission are grounded to a stud on the drive motor generator power inverter module (PIM) assembly.
3. Ensure the drive motor generator position sensor harness shield circuits are properly grounded prior to testing.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

1. «Component Connector End Views»(/cadillac/escalade/gmt900-2006-2014/remont/body-electrical/#wiring-systems-and-power-management-component-connector-end-views-index-a)
2. «Inline Harness Connector End Views»(/cadillac/escalade/gmt900-2006-2014/remont/body-electrical/#wiring-systems-and-power-management-inline-harness-connector-end-views-index)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Special Tools

DT-48493 Jumper Harness. See Special Tools .

1. Ignition OFF, disconnect PIM X1 connector.
2. Using the Position Sensor Specification table specifications listed below, test the position sensor resistance at the PIM X1 circuits as indicated. Use the specifications for the drive motor generator that set the DTC. Also test each circuit for a short to ground. If any of the circuits are not within specification, continue with testing. If all circuits test normal, inspect for proper terminal contact at PIM X1 connector. If PIM X1 terminal contact tests OK, perform the Intermittent Condition Testing below.
3. Disconnect the transmission X176 24-way connector.
4. Connect the DT-48493 to the X176 24-way connector at the transmission. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) .
5. Using the Position Sensor Specification table specifications listed below, test the position sensor resistance at the transmission X176 circuits as indicated. Use the specifications for the drive motor generator that set the DTC. Also test each circuit for a short to ground. If all circuits test normal, continue with testing. If any of the circuits are not within specification, test the internal transmission harness for the condition. If the internal transmission harness tests OK, replace the applicable drive motor generator.
6. Disconnect DT-48493 from the transmission X176 24-way connector. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) .
7. Connect DT-48493 to the transmission X176 24-way connector at the vehicle harness. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/engine-control-systems/#hybrid-engine-controls-special-tools-equipment) .
8. Disconnect PIM connector X1.
9. Using the PIM to Transmission Terminal Reference table listed below, test the vehicle harness continuity between PIM X1 and transmission X176. Use the specifications for the drive motor generator that set the DTC. Also test these circuits for short to ground and to the shield circuit if the shield circuit is not presently grounded to the PIM assembly. If any of the circuits are not within the specified range, repair or replace the wiring harness. If all circuits test normal, inspect transmission connector X176 for proper terminal contact. If transmission connector X176 tests OK, inspect the harness for an intermittent concern.

Intermittent Condition Testing

1. If possible, determine which of the position sensor circuits have the intermittent condition by reviewing the Diagnostic Fault Information table. For example, DTCs P0C57 and P0C52 only set for a short to ground condition on either the S1 or S3 circuit.
2. Using the Position Sensor Specification table listed below, monitor the position sensor circuits at PIM X1 connector while manipulating the applicable harness and connectors. If any of the circuits are not within specification, repair the harness or terminal as required. If a harness repair is indicated and external harness damage is not evident, the most likely location for internal wire damage is near the harness clamping locations.
3. Disconnect transmission X176 connector and inspect for the following: Proper terminal contact Proper terminal retention in the connector Foreign material or moisture Repair, replace or clean the connector as appropriate.
4. Reconnect all connectors and test drive the vehicle. If the DTC sets, replace the applicable drive motor generator and retest for DTCs. If the DTC sets, replace the PIM.

Drive Motor 1 Position Sensor Specification

Drive Motor Position Sensor 1 PIM to Transmission Terminal Reference

Drive Motor 2 Position Sensor Specification

Drive Motor 2 Position Sensor PIM to Transmission Terminal Reference

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for PIM replacement, setup and programming
2. «Drive Motor with Generator Assembly Removal - 1st Position»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Drive Motor with Generator Assembly Removal - 2nd Position»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
4. «Transmission Control Wiring Harness Extension Harness Removal»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator position sensor is monitored by the motor control module (MCM). The MCM monitors the angular position, speed and direction of the drive motor generator based upon the signals of the resolver-type position sensor. The position sensor allows the MCM to determine the exact position, speed and direction of the drive motor generator.

1. Ignition voltage is 8-18V.
2. MCM temperature and voltage out of range DTCs have not set.
3. Drive motor generator speed greater than 11,500 RPM.

The MCM detects drive motor generator speed greater than 10,000 RPM after an initial detection of greater than 11,500 RPM.

1. DTCs P1B0D and P1B0E are Type A DTCs.
2. The hybrid powertrain control module (HPCM) commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTCs P1B0D and P1B0E are Type A DTCs.

1. The drive axle and drive motor generator 2 are joined mechanically through a planetary gear set, any condition that allows the rear axle to rotate too fast while the transmission is in gear may cause DTC P1B0E to set. Ask the operator if the vehicle was subjected to downhill coasting at an excessive speed.
2. A transmission mechanical failure that occurs during high drive motor generator torque may cause these DTCs to set.
3. Any condition which causes either MCM to receive incorrect or corrupt GM LAN information may cause these DTCs to set. Inspect for communication DTCs.
4. Repeated drive motor generator operation at speeds in excess of the DTC limits may cause deterioration of the drive motor generator magnets.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Inspect for transmission control module (TCM) DTC P0723, any other DTCs that would indicate an internal transmission mechanical concern or any vehicle communication U-code DTCs. If any of the specified DTCs are set, repair them first. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Clear the DTC information.
3. Turn the ignition OFF for 1 minute.
4. Operate the vehicle under the conditions for running.
5. Retest for DTCs P1B0D and P1B0E. If the DTC resets, program the PIM with the latest software version and recheck for DTCs. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator position sensor is monitored by the motor control module (MCM). The MCM monitors the angular position, speed and direction of the drive motor generator based upon the signals of the resolver-type position sensor. The position sensor, or resolver, contains a drive coil, two driven coils and an irregular shaped metallic rotor. The metallic rotor is mechanically attached to the shaft of the drive motor generator. At ignition ON, the MCM outputs a 7 volt ac, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field surrounding the two driven coils and the irregular shaped rotor. The MCM then monitors the two driven coil circuits for a return signal. The position of the irregular shaped metallic rotor causes the magnetically-induced return signals of the driven coils to vary in size and shape. A comparison of the two driven coil signals allows the MCM to determine the exact position, speed and direction of the drive motor generator.

The position sensor is a non-serviceable part of the drive motor generator assembly.

A measurement called offset is needed for accurate determination of the motor position. Offset is the relationship between the position sensor and the drive motor generator output shaft. Whenever the ignition is cycled to OFF, the MCM attempts to learn the offset of the drive motor position sensor by rapidly oscillating the motor and observing the position sensor signals.

Condition 1, 2, 3 and 4

1. Hybrid wake-up signal is not active because the ignition has been transitioned from RUN to OFF.
2. The MCM has learned a valid drive motor position sensor offset value at least once.

Condition 2

Motor speed is less than 20 RPM.

Condition 1

Position sensor offset value not learned because drive motor speed is greater than 50 RPM.

Position sensor offset value not learned because hybrid battery voltage as observed at the MCM is less than 192V.

Condition 3

Position sensor offset value not learned because drive motor phase to phase current difference is less than 15 A.

Condition 4

Position sensor offset value not learned because the offset learn value is greater than the maximum allowed offset of 25 degrees.

1. P1B10 and P1B0F are Type C DTCs.
2. The MCM operates the drive motor generator using the last valid learned offset.

1. P1B10 and P1B0F are Type C DTCs.
2. High voltage remains enabled immediately following an ignition key transition from RUN to OFF.

Scan Tool Reference

Control Module References for scan tool information

1. Observe the BECM Contactor Sys. Req. Signal parameter. The HV contactor relays should be Closed, enabling the high voltage system. If the HV contactor relays are Open, diagnose and repair the DTCs which are preventing high voltage from being enabled.
2. Ignition OFF, wait 2 minutes.
3. Ignition ON, wait 2 minutes and then turn ignition OFF.
4. Ignition ON, monitor DTC Status. DTC P1B10 and P1B0F should have passed last test. If the DTC has passed, clear DTC Information. No further diagnosis of this DTC is necessary.

1. Inspect for DTCs P0A40, P0A45, P0A46, P0A78, P0A79, P0A3F, P0C05, P0C08, P0C0B, P0C0E, P0C4E, P0C4F, P0C52, P0C53, P0C57, P0C58, P0C61, P0C62, P0C5C, P0C5D, P1B03, P1B04 or P1B0D. If any of the above DTCs are set, diagnose and repair them prior to performing this diagnostic.
2. Ignition ON, engine OFF. Observe the BECM Hybrid Battery Pack Calculated parameter. The hybrid battery voltage should be greater than 192V. If the hybrid battery voltage is less than 192V, replace the drive motor generator battery.
3. Turn the ignition OFF and wait 2 minutes.
4. Ignition ON, monitor DTC Status. DTC P1B10 and P1B0F should have passed last test. If DTC P0C4E or P0C4F sets, proceed to that diagnostic procedure. If DTC P1B10 and P1B0F have passed, clear DTC Information. No further diagnosis is necessary. If DTC P1B10 or P1B0F resets, program the PIM with the latest software version and recheck for DTCs. If the DTC resets after programming or if the PIM already contains the latest software version, replace the applicable drive motor generator assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor with Generator Assembly Removal - 1st Position»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
2. «Drive Motor with Generator Assembly Removal - 2nd Position»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Drive Motor Generator Battery Replacement and Shipping Preparation»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system)
4. «Drive Motor Battery with Case Overhaul»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module (HPCM). The HPCM monitors its ability to read and write to the memory. The HPCM processor monitors the data to verify that the indicated brake torque request calculation is correct.

1. The control module runs the program to detect an internal fault when the key is ON.
2. Ignition voltage is 8-18V.

The control module has detected an internal malfunction.

1. DTC P1B15 is a Type A DTC.
2. The HPCM commands the battery energy control module (BECM) to open the high voltage contactor relays.

DTC P1B15 is a Type A DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Clear the DTC information.
2. Ignition OFF for 1 minute.
3. Ignition ON.
4. Retest for DTCs P1B15.

Program the PIM with the latest software version and recheck for DTCs.

1. If the DTC resets after programming or if the PIM already contains the latest software version, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The hybrid powertrain control module (HPCM) uses ignition 1 circuit terminal voltage to monitor the 12V system voltage. Ignition 1 circuit voltage also powers several of the internal drive motor generator power inverter control module (PIM) components.

Ignition is ON.

The control module has detected ignition 1 circuit voltage is 2V or less.

1. DTC P2534 is a Type A DTC.
2. The HPCM commands the engine OFF.

DTC P2534 is a Type A DTC.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Clear the DTC information.
2. Turn the ignition OFF for 1 minute.
3. Turn the ignition ON.
4. Retest for DTC P2534.

1. Ignition OFF, disconnect PIM connector X1.
2. Ignition ON, test the voltage on the ignition 1 circuit, between connector X1 terminal 20 and ground. The voltage should be within 0.5V of actual battery voltage. If not within the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the PIM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Aux. Trans. Fluid Pump Fault Status 1

Aux. Trans. Fluid Pump Fault Status 2

The auxiliary transmission fluid pump (ATFP) system supplies the transmission with hydraulic pressure when the vehicle is operating in the internal combustion engine (ICE) Autostop hybrid mode. The ATFP system consists of an ATFP control module that operates an electric, 12V 3 phase alternating current (ac), motor-driven pump. Two pulse width modulated (PWM) status circuits connect the ATFP control module to the hybrid powertrain control module (HPCM). The transmission auxiliary oil pump control circuit delivers the HPCM commanded pump speed to the ATFP control module. The transmission auxiliary oil pump diagnostic circuit supplies the HPCM with the actual pump speed and also with the operating status of the ATFP control module. The HPCM monitors these circuits for fault conditions.

The ATFP control module inverts 12V direct current (dc) into 12V, 3 phase ac current to operate the pump motor.

The ATFP control module monitors the status of the ATFP motor/pump as well as its own internal circuitry. The ATFP control module does not store its own diagnostic status. Current ignition cycle diagnostic status is reported to the HPCM over the transmission auxiliary oil pump diagnostic circuit. The diagnostic status within the ATFP control module is reset at every ignition-off cycle.

1. Ignition voltage is 8-18 volts.
2. The auxiliary transmission fluid pump is commanded ON.

The HPCM observes the difference between actual and commanded ATFP pump speed is greater than 500 RPM for 4 out of 4.125 seconds.

1. DTC P2797 is a Type B DTC.
2. The drive motor generator power inverter control module (PIM) disables the Autostop hybrid mode.

DTC P2797 is a Type B DTC.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 38522: Variable Signal Generator

For equivalent regional tools, refer to Special Tools .

1. Ignition ON with the engine OFF, command the Aux. Trans. Pump Speed to 50 percent with the scan tool. Attempt to maintain pump operation for at lease 60 seconds.
2. Observe the aux. trans. fluid pump actual display and the aux. trans. fluid pump commanded displays with the scan tool. Actual pump speed should be maintained within 10 percent of commanded. The pump should not make excessive noise or stall. If the actual speed is within 10 percent of commanded speed an electrical fault condition is not currently present, if an aux. trans. fluid pump pressure fault is suspected, test the aux. trans. pump line pressure output. Refer to «Line Pressure Check»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-symptom-troubleshooting-diagnosis__line-pressure-check) . If the difference between actual and commanded speed is greater than 10 percent, the pump is noisy, or the pump stalls, proceed to Circuit/System Testing.

1. Inspect for DTC P0C2B. Diagnose P0C2B before performing this procedure.
2. Ignition ON, engine OFF, observe the Aux. Trans. Fluid Pump Fault Status 1 and Aux. Trans. Fluid Fault Status 2 displays with the scan tool.
3. Command the aux. trans. fluid pump speed to 50 percent with the scan tool while observing the fault status displays. Refer to the applicable diagnostic procedure below for the fault status indicated by the scan tool display. If No Fault status is displayed, review the Freeze Frame/Failure Records and perform the diagnosis indicated by the Fault Status parameter display.

PWM Input Fault

1. Ignition OFF, disconnect PIM connector X1.
2. Ignition ON, test for 11-13V on the Trans. Aux. Oil Pump Control circuit from PIM connector X1 terminal 3 and chassis ground. If less than the specified range, test the control circuit for an open or short to ground. If the circuit tests normal, replace the ATFP Control Module.
3. Pre-Adjust the J 38522: variable signal generator to 50 percent duty cycle @ 250 Hz.
4. Connect the J 38522: variable signal generator to the Trans. Aux. Oil Pump Control circuit, from the PIM connector X1 terminal 3 and ground and listen for auxiliary transmission fluid pump motor operation. If pump operation is audible, replace the PIM. If pump operation is not audible, continue with Circuit/System Testing.
5. Ignition OFF, disconnect the ATFP control module connector X1.
6. Ignition ON, test for 0V on the Trans. Aux. Oil Pump control circuit from PIM connector X1 terminal 3 and chassis ground. If greater than the specified range, test the control circuit for a short to voltage. If equal to the specified range, replace the ATFP control module.

Motor/Open Short

This display indicates the ATFP control module has detected one of the following pump motor current conditions

1. At least one phase current is more than 70 A.
2. Commanded current is more than 5 A and actual current in any phase is less than 2 A.

1. Ignition OFF, disconnect the ATFP control module connector X2.
2. Using the Auxiliary Fluid Pump Specification table listed below, test the resistance between the X2 circuits of the pump connector as indicated. If any of the circuits are not within the specified range, replace the pump assembly and repeat the Circuit/System Verification. If all circuits test normal, replace the ATFP control module and repeat Circuit/System Verification.

Auxiliary Fluid Pump Specification

Motor CKT Fault

This display indicates an internal ATFP control module fault exists, no external circuits are involved. Replace the ATFP control module.

Temp Sen Fault

This display indicates an internal ATFP control module fault exists, no external circuits are involved. Replace the ATFP control module.

Low Voltage

1. This display indicates the ATFP control module has monitored battery voltage of less than 12.6V.
2. Measure actual battery voltage with a DMM. If actual battery voltage measures less than the value range, increase actual battery voltage and repeat Circuit/System Testing. If actual battery voltage measures more than the value range, test the ATFP control module power and ground circuits for a high resistance condition. If the circuits test normal, replace the ATFP control module.

ATFPCM Over temp

1. This display indicates the ATFP control module circuit board has reached a temperature of 115-125°C (239-257°F).
2. Measure the actual temperature of the ATFP control module case. If actual temperature is the same or more than the value range, no action is necessary. If actual temperature is less than the value range, replace the ATFP control module.

ATFPCM Hot

1. This display indicates the ATFP control module circuit board has reached a temperature of more than 125°C (257°F).
2. Measure the actual temperature of the ATFP control module case. If actual temperature is the same or more than the value range, no action is necessary. If actual temperature is less than the value range, replace the ATFP control module.

Current High/Lo

1. This display indicates the ATFP control module has monitored motor current that is outside the normal range for a given motor speed.
2. Inspect for the following conditions: Low or cavitating automatic transmission fluid Poor terminal connection or wiring degradation External indication of ATFP pump motor damage

1. If none of the conditions are observed, replace the ATFP motor/pump assembly and the ATFP control module.

Current Fault

This display indicates an internal ATFP control module fault exists, no external circuits are involved. Replace the ATFP control module.

Unable to Start

1. This display indicates the ATFP control module has monitored motor current of more than 20 A during motor start-up.
2. Inspect for the following conditions: Automatic transmission fluid pressure trapped internally Poor terminal connection or wiring degradation External indication of ATFP pump motor damage

1. If none of the conditions are observed, replace the ATFP motor/pump assembly and the ATFP control module.

No PWM Response

This display indicates the HPCM does not detect the ATFP Control Feedback circuit signal. Refer to DTC P0C2B .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for PIM or ATFP control module replacement, setup, and programming
2. «Auxiliary Fluid Pump and Gasket Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle)

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Hybrid Controls Schematics
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Special Tools
• Diagnostic Repair Verification
• Manual Shift Shaft Position Switch Replacement
• Transmission Control Wiring Harness Extension Harness Removal
• DTC P1824, P182A-P182F, P1838, or P1839
• Drive Motor Generator Control Module Description and Operation
• Power Steering Assist Motor Replacement
• DTC P0AF7
• Engine Controls Schematics
• High Voltage Disabling
• Diagnostic Trouble Code (DTC) List - Vehicle
• DTC P1AE6 or P1AE7
• Battery Negative Cable Disconnection and Connection
• High Voltage System Diagnosis (EL-48458)
• Drive Motor Generator Battery Control Module Scan Tool Information
• Generator Control Module 3-Phase Cable Assembly Replacement
• Air Conditioning Compressor Replacement (HP2)
• Inline Harness Connector End Views
• Line Pressure Check
• DTC P0C2B