AutoCodes – Generic – P1F20

P1F20 Code - Generator Motor Inverter Power Supply Voltage Low

Quick Answer

The Voltage Control Unit (VCU) monitors decrease in the supplied 12 volt power supply voltage at all times and sends the judgment result to the motor control module (generator) via serial communication. Common causes include Faulty Voltage Control Unit (VCU), Voltage Control Unit (VCU) harness is open or shorted, Voltage Control Unit (VCU) circuit poor electrical connection. 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: P1F20 indicates Generator Motor Inverter Power Supply Voltage Low.
Common causes: Common causes include Faulty Voltage Control Unit (VCU), Voltage Control Unit (VCU) harness is open or shorted, Voltage Control Unit (VCU) circuit poor electrical connection.
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 1,267

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 Apr 25, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1F20 Description

The Voltage Control Unit (VCU) monitors decrease in the supplied 12 volt power supply voltage at all times and sends the judgment result to the motor control module (generator) via serial communication. The motor control module (generator) detects a malfunction and stores a DTC when the 12 volt power supply voltage decrease judgment result is received from the VCU continuously for the prescribed time or more.

OBDII Code P1F20 - Generator Motor Inverter Power Supply Voltage Low - AutoCodes.com — P1F20 Code - Generator Motor Inverter Power Supply Voltage Low

What does this mean?

What are the Possible Causes of the DTC P1F20?

Faulty Voltage Control Unit (VCU)
Voltage Control Unit (VCU) harness is open or shorted
Voltage Control Unit (VCU) circuit poor electrical connection
Faulty Motor Control Module (Generator)

How to Fix the DTC P1F20?

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 P1F20 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 P1F20 code?

Need more information on how to fix the P1F20 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1F20 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1F20 Acura — Generator Motor Inverter Power Supply Voltage Low
P1F20 Honda — Generator Motor Inverter Power Supply Voltage Low

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 P1F20 Code

1. What does the OBDII code P1F20 mean?

P1F20 indicates that the vehicle's generator motor inverter is experiencing a low power supply voltage, which may impact hybrid or electric drive functions.

2. What are the common symptoms of a P1F20 code?

Symptoms include reduced engine performance, limited hybrid or electric functionality, warning lights on the dashboard, and possible failure to start the vehicle.

3. What causes the P1F20 code to trigger?

Common causes include a faulty generator motor inverter, a weak or damaged high-voltage battery, wiring issues, or problems with the inverter power supply circuit.

4. Can I drive with a P1F20 code?

It's not recommended to drive with a P1F20 code, as it could lead to further damage to the hybrid or electric drive system and potential safety concerns.

5. How is the P1F20 code diagnosed?

A technician will use a scan tool to read the code, inspect the inverter power supply circuit, test the high-voltage battery, and check for wiring or connection issues.

6. How do I fix the P1F20 code?

Repairs may involve replacing the generator motor inverter, repairing or replacing damaged wiring, or addressing issues with the high-voltage battery.

7. How much does it cost to fix a P1F20 code?

The repair cost depends on the root cause, but replacing a generator motor inverter can cost between $1,000 and $3,000, while wiring repairs may be less expensive.

8. Can a weak high-voltage battery cause a P1F20 code?

Yes, a weak or failing high-voltage battery can result in insufficient power to the generator motor inverter, triggering the P1F20 code.

9. What tools are needed to troubleshoot a P1F20 code?

Tools include an advanced OBDII scan tool, a multimeter to check wiring and voltage, and access to the vehicle's service manual for circuit diagrams.

10. Is the P1F20 code specific to hybrid and electric vehicles?

Yes, the P1F20 code is typically found in hybrid or electric vehicles due to their use of a generator motor inverter and high-voltage battery systems.