P0AFA
DTC P0AFA
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 Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0AFA
- Hybrid Battery System Voltage Low - ACCM 300V
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The air conditioner control module (ACCM) monitors the high voltage direct current (HVDC) voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range. If the ACCM detects low HVDC voltage, then DTC P0AFA will set.
Conditions for Running the DTC
* The engine is running or is in autostop mode.
* The 12V system voltage is between 9.5-18 V.
Conditions for Setting the DTC
The ACCM detects that the hybrid battery voltage is less than 191 volts for 3 seconds.
Action Taken When the DTC Sets
The air conditioning is disabled.
Conditions for Clearing the DTC
* The DTC will pass when the ACCM detects a hybrid battery voltage greater than 201 V for 3 seconds.
* A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
Reference Information
Schematic Reference
* HVAC Schematics (HVAC - Automatic)
* Hybrid Controls Schematics ()
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
* Heating and Air Conditioning System Description and Operation (HP2) ()
* High Voltage Monitoring Systems Description ()
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)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
EL-48900 HEV Safety Kit
Circuit/System Verification
1. Verify that no hybrid powertrain control module (HPCM) or engine control module (ECM) DTCs are set that indicate generator, HPCM, or battery failure, or that disable the high voltage.
• If the specified DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle).
2. Engine running or autostop, observe the scan tool accessory DC power control module (APM) HPCM 300V Circuit parameter. The reading should be between 225 V and 380 V.
• If not within the specified range, refer to Jump Assist ().
3. Ignition ON, observe the scan tool ACCM High Battery Voltage parameter. The reading should be between 225 V and 380 V.
Circuit/System Testing
Danger: 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.
1. Disable the high voltage, and remove the 3 phase cable cover. Refer to High Voltage Disabling ().
2. Ignition OFF, verify that the air conditioner compressor HVDC terminal bolts are present and are torqued to specification.
• If the bolts are missing or are not tight, replace any damaged components, install and tighten the bolts.
3. If all circuits test normal, replace the ACCM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Control Module References (Programming and Relearning) for ACCM replacement, setup, and programming