Diesel Data: Automotive Repair
Home >> Chevrolet >> 2011 >> Volt L4-1.4L Elect >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P1AF0

P1AF0




DTC P1AF0 or P1AF2

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructionsprovides an overview of each diagnostic category.

DTC Descriptor
DTC P1AF0
- Drive Motor 1 Control Module Hybrid Battery Voltage System Isolation Lost

DTC P1AF2
- Drive Motor 2 Control Module Hybrid Battery Voltage System Isolation Lost

Circuit/System Description

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

Motor control modules loss of isolation is detected through the use of two high-impedance resistors and voltage measuring circuitry. The two resistors are connected in series between the high voltage positive and high voltage negative circuits. The center connection of the two resistors is also connected to vehicle chassis. The motor control module then measures the voltage drop across one of the resistors. Without a loss of isolation, the motor control module 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.

Conditions for Running the DTC

* The high voltage contactor relays are closed.
* High voltage is greater than 50 V.
* Ignition voltage is 8-18 V.
* DTCs P1AEE, P1AF4, and P1AF5 are not set.

Conditions for Setting the DTC

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

OR

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

Action Taken When the DTC Sets

DTCs P1AF0 and P1AF2 are Type C DTCs.

Conditions for Clearing the DTC

DTCs P1AF0 and P1AF2 are Type C DTCs.

Reference Information
Schematic Reference

Hybrid Controls Schematics Hybrid Controls Schematics
Connector End View Reference

Component Connector End Views Hybrid/EV Battery Pack X1 A4
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference

Control Module References Control Module Referencesfor scan tool information
Special Tools

* EL-50322 - Pre-Charge Test Tool
* EL-48569 - Terminal Covers

For equivalent regional tools, refer to Special Tools Tools and Equipment.

Circuit/System Verification

1. Verify that DTC P1F0E is not set.

• If the DTC is set, refer to DTC P0AA6, P1AE6, or P1F0E P0AA6.

2. Verify that DTC P0A78, P0A79, P0BFD, P0BFE, P0C01, or P0C04 is not set.

• If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

3. Ignition ON, engine OFF, observe the scan tool BECM contactor system status parameter. The status should display closed.

• If not the specified value, refer to Symptoms - Hybrid Controls Symptoms - Hybrid Controls.

4. Hood closed, transmission in park, and Ignition OFF for at least 2 minutes.
5. Ignition ON, engine OFF, within 5 seconds of ignition ON, observe the HPCM 300V Circuit parameter and compare it to both data parameters listed below. Each motor parameter should be within 20 V of the HPCM 300 V circuit parameter.

* Motor 1 Isolation Voltage
* Motor 2 Isolation Voltage

• If only one Motor Isolation Voltage value is not within the specified range, replace the drive motor generator power inverter control module.
• If both Motor Isolation Voltage values are not within the specified range, refer to DC Circuit Testing.

6. If both Motor Isolation Voltage values are within the indicated range, a loss of isolation condition is not currently present, refer to AC Circuit Testing.

Circuit/System Testing

DC Circuit Testing

AC Circuit Testing

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* 300-Volt Battery Positive and Negative Cable Replacement (Drive Motor Battery-to-Inverter ) 300-Volt Battery Positive and Negative Cable Replacement (Drive Motor Battery-to-Inverter )300-Volt Battery Positive and Negative Cable Replacement (Inverter-to-Compressor/Heater Module) 300-Volt Battery Positive and Negative Cable Replacement (Inverter-to-Compressor/Heater Module)300-Volt Battery Positive and Negative Cable Replacement (Drive Motor Battery-to-APM Module) 300-Volt Battery Positive and Negative Cable Replacement (Drive Motor Battery-to-APM Module)300-Volt Battery Positive and Negative Cable Replacement (Drive Motor Battery-to-Charger) 300-Volt Battery Positive and Negative Cable Replacement (Drive Motor Battery-to-Charger)for Drive Motor Battery-to-Inverter
* Air Conditioning Compressor Replacement
* Drive Motor Generator Rotor and Stator Removal - Unit A 11. Drive Motor Generator Rotor and Stator Removal - Unit Afor Drive Motor 1 or Drive Motor 1 3-Phase Cable Assembly replacement
* Drive Motor Generator Rotor and Stator Removal - Unit B 18. Drive Motor Generator Rotor and Stator Removal - Unit Bfor Drive Motor 2 or Drive Motor 2 3-Phase Cable Assembly replacement
* Control Module References Control Module References for Drive Motor Generator Power Inverter Module and Accessory DC Power Control Module replacement, setup, and programming.

Diesel-Data.com