AutoCodes – Generic – C0402

C0402 Code - Transfer Case Solenoid Valve

Quick Answer

The rear drive clutch solenoid valve is internal to the torque transfer device housing. Common causes include Faulty Transfer Case Solenoid Valve, Transfer Case Solenoid Valve harness is open or shorted, Transfer Case Solenoid 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: C0402 indicates Transfer Case Solenoid Valve.
Common causes: Common causes include Faulty Transfer Case Solenoid Valve, Transfer Case Solenoid Valve harness is open or shorted, Transfer Case Solenoid 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 4,844

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 Jul 04, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code C0402 Description

The rear drive clutch solenoid valve is internal to the torque transfer device housing. The rear differential clutch control module supplies battery voltage to the control circuit and ground to the low reference circuit of the solenoid valve. The solenoid valve is controlled by a pulse width modulation (PWM) signal. The solenoid valve controls the hydraulic pressure to the clutch package of the torque transfer device. The locking level of the torque transfer device depends on the engagement of the clutch package.

OBDII Code C0402 - Transfer Case Solenoid Valve - AutoCodes.com — C0402 Code - Transfer Case Solenoid Valve

What does this mean?

What are the Possible Causes of the DTC C0402?

Faulty Transfer Case Solenoid Valve
Transfer Case Solenoid Valve harness is open or shorted
Transfer Case Solenoid Valve circuit poor electrical connection

How to Fix the DTC C0402?

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 does this mean?

Code Tech Notes

- C0402 02 Transfer Case Solenoid Valve Short to Ground
- C0402 04 Transfer Case Solenoid Valve Open
- C0402 42 Transfer Case Solenoid Valve Calibration Not Programmed
- C0402 43 Transfer Case Solenoid Valve EEPROM Incorrect Programming
- C0402 4B Transfer Case Solenoid Valve Calibration Not Learned
- C0402 61 Transfer Case Solenoid Valve Stuck

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C0402 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 C0402 code?

Need more information on how to fix the C0402 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C0402 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

C0402 Buick — Transfer Case Solenoid Valve
C0402 Cadillac — Transfer Case Solenoid Valve
C0402 Chevrolet — Transfer Case Solenoid Valve
C0402 GMC — Transfer Case Solenoid Valve

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 C0402 Code

1. What are the common symptoms of OBDII code C0402 related to the Transfer Case Solenoid Valve?

- Common symptoms include difficulty engaging or disengaging four-wheel drive, erratic shifting, and a flashing four-wheel drive indicator light.

2. What are the possible causes of OBDII code C0402 related to the Transfer Case Solenoid Valve?

- The code C0402 can be triggered by a faulty transfer case solenoid valve, wiring issues, low transfer case fluid levels, or a malfunctioning transfer case actuator.

3. How can I diagnose the cause of OBDII code C0402 related to the Transfer Case Solenoid Valve?

- Diagnosing the issue involves checking the wiring connections, inspecting the transfer case solenoid valve for proper operation, testing the transfer case actuator, and ensuring the transfer case fluid levels are correct.

4. Can I continue driving my vehicle with OBDII code C0402 related to the Transfer Case Solenoid Valve?

- It is not recommended to drive your vehicle with this code present, as it can lead to further damage to the transfer case components and affect the drivability of your vehicle.

5. How can I repair OBDII code C0402 related to the Transfer Case Solenoid Valve?

- Repairing this code may involve replacing the transfer case solenoid valve, repairing any damaged wiring, servicing the transfer case fluid, or replacing the transfer case actuator if necessary.

6. Is it possible to reset OBDII code C0402 related to the Transfer Case Solenoid Valve without fixing the issue?

- While you can clear the code temporarily, it will likely reappear until the underlying issue with the transfer case solenoid valve is resolved.

7. Are there any DIY tips for troubleshooting OBDII code C0402 related to the Transfer Case Solenoid Valve?

- You can start by checking the transfer case fluid level, inspecting the wiring connections, and listening for any unusual noises coming from the transfer case when engaging four-wheel drive.

8. Can a faulty transfer case solenoid valve cause other OBDII codes to appear?

- Yes, a malfunctioning transfer case solenoid valve can trigger related codes such as P0776 or P0777, indicating issues with the shift solenoid or pressure control solenoid.

9. How long does it typically take to repair OBDII code C0402 related to the Transfer Case Solenoid Valve?

- The repair time can vary depending on the specific issue, but it may take a few hours to a full day to diagnose and replace the faulty components.

10. Will fixing OBDII code C0402 related to the Transfer Case Solenoid Valve improve my vehicle's performance?

- Yes, resolving this code will help restore proper four-wheel drive functionality and ensure smooth shifting, ultimately improving your vehicle's performance and drivability.