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AutoCodes – Generic – C0403

C0403 Code - AWD Oil Filter Reverse Valve Stuck Open

Quick Answer

The differential clutch pump delivers hydraulic oil pressure to the rear drive clutch solenoid valve and the rear differential clutch solenoid valve. Common causes include Faulty AWD Oil Filter Reverse Valve, AWD Oil Filter Reverse Valve harness is open or shorted, AWD Oil Filter Reverse Valve 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
C0403 indicates AWD Oil Filter Reverse Valve Stuck Open.
Common causes
Common causes include Faulty AWD Oil Filter Reverse Valve, AWD Oil Filter Reverse Valve harness is open or shorted, AWD Oil Filter Reverse Valve 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 4,621
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Jul 04, 2020
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Code C0403 Description

The differential clutch pump delivers hydraulic oil pressure to the rear drive clutch solenoid valve and the rear differential clutch solenoid valve. The pump is mounted to the torque transfer device housing. The pressure of the system is calculated by the rear differential clutch control module which monitors the differential clutch pump current levels. When the pressure reaches approximately 3200 kPa (464 psi), the rear differential clutch control module determines that the system pressure has been obtained and deacvitates the differential clutch pump. If a voltage is detected after a predetermined time limit when the pump has been deactivated an error is detected. This condition indicates the pump is spinning backwards.
OBDII Code C0403 - AWD Oil Filter Reverse Valve Stuck Open - AutoCodes.com
C0403 Code - AWD Oil Filter Reverse Valve Stuck Open
What does this mean?

What are the Possible Causes of the DTC C0403?

  • Faulty AWD Oil Filter Reverse Valve
  • AWD Oil Filter Reverse Valve harness is open or shorted
  • AWD Oil Filter Reverse Valve circuit poor electrical connection

How to Fix the DTC C0403?

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 C0403 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 C0403 code?

Need more information on how to fix the C0403 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C0403 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

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 C0403 Code

1. What does the OBDII code C0403 mean?

C0403 indicates that the All-Wheel Drive (AWD) oil filter reverse valve is stuck open, potentially causing issues with AWD system functionality.

2. What are common symptoms of the C0403 code?

Symptoms may include reduced AWD performance, warning lights on the dashboard, or unusual noises from the drivetrain.

3. What causes the AWD oil filter reverse valve to get stuck open?

Common causes include dirt or debris in the valve, lack of proper maintenance, or mechanical failure of the valve itself.

4. Can I drive with the C0403 code active?

While the vehicle may still be drivable, AWD functionality could be compromised, especially in slippery or off-road conditions.

5. How is the C0403 code diagnosed?

A mechanic will typically inspect the AWD system, check for debris or damage in the reverse valve, and use a diagnostic scanner to confirm the code.

6. What repairs are needed for the C0403 code?

Repairs may include cleaning or replacing the reverse valve, flushing the AWD system fluid, or replacing the AWD oil filter.

7. How much does it cost to fix the C0403 code?

Repair costs can range from $100 to $500, depending on whether the issue is resolved by cleaning or requires part replacement.

8. Can neglecting AWD system maintenance cause the C0403 code?

Yes, failing to replace the AWD fluid or oil filter at recommended intervals can lead to debris buildup and valve issues.

9. How can I prevent the C0403 code from recurring?

Regular maintenance, including timely fluid changes and inspections of the AWD system, can help prevent this code.

10. Will clearing the C0403 code with a scanner fix the problem?

Clearing the code will remove the error temporarily, but if the underlying issue isn’t addressed, the code will likely return.

Discuss the causes and fixes for C0403 OBDII Code

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