P1ABB
DTC P1AA8, P1AB9, P1ABA, or P1ABB
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P1AA8
- Starter/Generator Field Control Performance
DTC P1AB9
- Starter/Generator Field Coil Current Sensor Circuit Low Voltage
DTC P1ABA
- Starter/Generator Field Coil Current Sensor Circuit High Voltage
DTC P1ABB
- Starter/Generator Field Coil Current Sensor Overcurrent
Circuit/System Description
The starter/generator control module (SGCM) monitors the motor generator unit (MGU) field coil circuit to see if the field coil current is within tolerance. If a fault is detected, the appropriate DTC will set.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
P1AA8
Field coil current - command current is greater than 0.5A for 1.0 second.
P1AB9
Sensor output voltage less than +1.8 volts (-2A) for 20 ms.
P1ABA
Sensor output voltage greater than 4.1 volts (10A) for 20 ms.
P1ABB
Field coil current is greater than 6A for 20 ms.
Action Taken When the DTC Sets
Stop PWM (MGU shutdown)
Conditions for Clearing the DTC
The DTC will clear 30 seconds after the ignition is turned OFF and then turned back ON, enabling the module cycle wakeup signal.
Diagnostic Aids
P1AA8
Possible cable open or short to ground.
P1AB9, P1ABA
Possible open circuit or faulty cable connection.
P1ABB
Possible short circuit or faulty cable connection.
Reference Information
Schematic Reference
Hybrid Controls Schematics ()
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Testing
Caution: To help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.
1. Verify that the latest service software is installed.
2. Disconnect harness connector X2 from the SGCM. Refer to Generator Control Module Replacement ().
3. Using the appropriate test adapters, test for 5-100 ohms resistance between terminals 9 and 12.
• If within the specified range, replace the SGCM.
4. Disconnect the 7 pin X1 connector at the MGU. Refer to Generator with Starter Replacement ().
5. Test for less than 1 ohm between SGCM connector harness terminal 12 and the MGU X1 connector harness terminal A.
• If greater than the specified value, repair the open circuit.
6. Test for less than 1 ohm between SGCM connector harness terminal 9 and the MGU X1 connector harness terminal C.
• If greater than the specified value, repair the open circuit.
7. Test for no continuity between SGCM connector harness terminal 9 and terminal 12.
• If greater than the specified value, repair the shorted circuits.
8. Test for short between SGCM connector harness terminal 12 and ground.
• If greater than the specified value, repair the shorted circuit.
9. If both circuits test normal, replace the MGU.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Generator with Starter Replacement ()
* Control Module References (Programming and Relearning) for SGCM replacement, setup, and programming