AutoCodes – Generic – P1AF4

P1AF4 Code - Drive Motor 1 Control Module Hybrid Battery Voltage Isolation Sensor Circuit Low Voltage

Quick Answer

The drive motor generator Power Inverter Control Module (PIM) contains two Motor Control Modules (MCMs). Common causes include Reprogram Power Inverter Control Module (PIM), Faulty Power Inverter Control Module (PIM), Power Inverter Control Module (PIM) harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1AF4 indicates Drive Motor 1 Control Module Hybrid Battery Voltage Isolation Sensor Circuit Low Voltage.
Common causes: Common causes include Reprogram Power Inverter Control Module (PIM), Faulty Power Inverter Control Module (PIM), Power Inverter Control Module (PIM) harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 3,024

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 05, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1AF4 Description

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 Ff 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.

OBDII Code P1AF4 - Drive Motor 1 Control Module Hybrid Battery Voltage Isolation Sensor Circuit Low Voltage - AutoCodes.com — P1AF4 Code - Drive Motor 1 Control Module Hybrid Battery Voltage Isolation Sensor Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1AF4?

Reprogram Power Inverter Control Module (PIM)
Faulty Power Inverter Control Module (PIM)
Power Inverter Control Module (PIM) harness is open or shorted
Power Inverter Control Module (PIM) circuit poor electrical connection

How to Fix the DTC P1AF4?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1AF4 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P1AF4 code?

Need more information on how to fix the P1AF4 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1AF4 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1AF4 Buick — Drive Motor 1 Control Module Hybrid Battery Voltage Isolation Sensor Circuit Low Voltage
P1AF4 Cadillac — Drive Motor 1 Control Module Hybrid Battery Voltage Isolation Sensor Circuit Low Voltage
P1AF4 Chevrolet — Drive Motor 1 Control Module Hybrid Battery Voltage Isolation Sensor Circuit Low Voltage
P1AF4 GMC — Drive Motor 1 Control Module Hybrid Battery Voltage Isolation Sensor Circuit Low Voltage
P1AF4 Saturn — Drive Motor 1 Control Module Hybrid Battery Voltage Isolation Sensor Circuit Low Voltage

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1AF4 Code

1. What are the common symptoms of OBDII code P1AF4?

- Common symptoms include reduced hybrid system performance, illuminated check engine light, and potential difficulty starting the vehicle.

2. What causes the OBDII code P1AF4 to trigger?

- The code P1AF4 is typically triggered by a fault in the drive motor 1 control module hybrid battery voltage isolation sensor circuit, resulting in low voltage readings.

3. How serious is the OBDII code P1AF4?

- The code P1AF4 should be addressed promptly to prevent further damage to the hybrid battery system and maintain the optimal performance of the vehicle.

4. Can I continue driving with the OBDII code P1AF4 present?

- It is not recommended to continue driving with the code P1AF4 present, as it can lead to potential issues with the hybrid system and may cause further damage if left unattended.

5. How can I diagnose the cause of OBDII code P1AF4?

- Diagnosis typically involves using a scan tool to retrieve the code, followed by inspecting the drive motor 1 control module hybrid battery voltage isolation sensor circuit for any visible damage or loose connections.

6. What are some repair tips for resolving OBDII code P1AF4?

- Repair tips may include checking and repairing any damaged wiring or connections in the sensor circuit, replacing the faulty sensor if necessary, and clearing the code to see if the issue persists.

7. Can a DIY enthusiast fix OBDII code P1AF4 at home?

- While some enthusiasts may have the skills to diagnose and repair the issue causing the code P1AF4, it is recommended to seek professional help, especially when dealing with complex hybrid system components.

8. How much does it typically cost to repair OBDII code P1AF4?

- The cost of repairing the OBDII code P1AF4 can vary depending on the extent of the issue, the need for replacement parts, and labor costs. It is advisable to obtain estimates from qualified mechanics.

9. Are there any preventive measures to avoid OBDII code P1AF4 in the future?

- Regular maintenance of the hybrid system, including checking the sensor circuit for signs of wear or damage, can help prevent issues that may trigger the OBDII code P1AF4.

10. Is it safe to reset the OBDII code P1AF4 using a scan tool?

- Resetting the code P1AF4 using a scan tool is safe after addressing the underlying issue that triggered the code. However, if the problem persists, further diagnosis and repairs may be necessary.