AutoCodes – Ford – P0812 2003 Ford F150

P0812 2003 Ford F150 Code - Reverse Switch Input Circuit Malfunction

Quick Answer

The Transmission Control Module (TCM) monitors the Reverse Switch Input signal. Common causes include Faulty Reverse Input Switch, Reverse Input Switch harness is open or shorted, Reverse Input Switch 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: P0812 2003 Ford F150 indicates Reverse Switch Input Circuit Malfunction .
Common causes: Common causes include Faulty Reverse Input Switch, Reverse Input Switch harness is open or shorted, Reverse Input Switch 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 2,265

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 May 09, 2019

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 P0812 2003 Ford F150 Description

The Transmission Control Module (TCM) monitors the Reverse Switch Input signal. The TCM sets the OBDII code when the Reverse Switch Input is not to factory specifications.

OBDII Code P0812 2003 Ford F150 - Reverse Switch Input Circuit Malfunction - AutoCodes.com — P0812 2003 Ford F150 Code - Reverse Switch Input Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC P0812 2003 Ford F150?

Faulty Reverse Input Switch
Reverse Input Switch harness is open or shorted
Reverse Input Switch circuit poor electrical connection
Damaged PCM

How to Fix the DTC P0812 2003 Ford F150?

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

The DTC indicates that the voltage is high when it should be low.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0812 2003 Ford F150 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 P0812 2003 Ford F150 code?

Need more information on how to fix the P0812 2003 Ford F150 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0812 2003 Ford F150 code diagnosed by a professional: Find a repair shop in your area

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 P0812 2003 Ford F150 Code

1. What does the OBDII code P0812 mean on a 2003 Ford F150?

P0812 indicates a "Reverse Switch Input Circuit Malfunction," meaning the Powertrain Control Module (PCM) has detected an issue with the circuit responsible for monitoring the reverse gear input.

2. What are the common symptoms of code P0812 on a 2003 Ford F150?

Common symptoms include the reverse lights not working, the reverse gear not engaging properly, or an illuminated Check Engine Light.

3. What causes the P0812 code to appear on a 2003 Ford F150?

Possible causes include a faulty reverse gear switch, damaged or corroded wiring, a disconnected connector, or a malfunctioning PCM.

4. How do I diagnose the P0812 code on my Ford F150?

Start by inspecting the reverse switch and its wiring for damage or loose connections. Use a multimeter to test the switch and circuit continuity.

5. Can a faulty reverse switch cause the P0812 code?

Yes, a faulty or stuck reverse switch is a common cause of this code, as it fails to send the proper signal to the PCM.

6. Is it safe to drive with a P0812 code on my 2003 Ford F150?

While the truck may still drive, issues like non-functioning reverse lights can pose safety risks, and prolonged use could lead to further damage.

7. How do I fix the P0812 code on a 2003 Ford F150?

Repairs may include replacing the reverse gear switch, repairing damaged wiring, cleaning corroded connectors, or, in rare cases, reprogramming or replacing the PCM.

8. How much does it cost to repair the P0812 code on a Ford F150?

Repair costs can range from $50 to $200, depending on whether the issue is with the switch, wiring, or connectors. PCM replacement, if needed, can be more expensive.

9. Can a blown fuse cause the P0812 code?

Yes, a blown fuse in the reverse light circuit can disrupt the signal and trigger the P0812 code.

10. How can I prevent the P0812 code from occurring again?

Regularly inspect and maintain your truck's wiring and connectors, ensure the reverse switch is functioning properly, and address electrical issues promptly.