AutoCodes – Ford – B1578 Ford

B1578 Ford Code - Lamp Park Input Circuit Short To Ground

Quick Answer

The Smart Junction Box (SJB) monitors the parking lamp request input from the headlamp switch. Common causes include Faulty Headlamp Switch, Headlamp Switch harness is open or shorted, Headlamp 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: B1578 Ford indicates Lamp Park Input Circuit Short To Ground.
Common causes: Common causes include Faulty Headlamp Switch, Headlamp Switch harness is open or shorted, Headlamp 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.

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Code Popularity 6,198

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 Feb 26, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1578 Ford Description

The Smart Junction Box (SJB) monitors the parking lamp request input from the headlamp switch. The SJB provides a ground for the parking lamp relay coil (integrated into the SJB ) when a request for the parking lamps is received. When the parking lamp relay is energized, voltage is routed to the rear and front parking lamps. The Diagnostic Trouble Code (DTC) sets when the SJB detects a short to ground from the parking lamps on input circuit.

OBDII Code B1578 Ford - Lamp Park Input Circuit Short To Ground - AutoCodes.com — B1578 Ford Code - Lamp Park Input Circuit Short To Ground

What does this mean?

What are the Possible Causes of the DTC B1578 Ford?

Faulty Headlamp Switch
Headlamp Switch harness is open or shorted
Headlamp Switch circuit poor electrical connection
Faulty Smart Junction Box (SJB)

How to Fix the DTC B1578 Ford?

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 B1578 Ford 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 B1578 Ford code?

Need more information on how to fix the B1578 Ford code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1578 Ford 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 B1578 Ford Code

1. What are the common symptoms of OBDII code B1578 in a Ford vehicle?

The common symptoms of OBDII code B1578 (Lamp Park Input Circuit Short To Ground) in a Ford vehicle include malfunctioning exterior lighting, such as headlights, taillights, or parking lights.

2. What causes the OBDII code B1578 to trigger in a Ford vehicle?

The OBDII code B1578 is typically triggered in a Ford vehicle due to a short circuit in the lamp park input circuit, which causes the system to detect a ground fault.

3. How can I diagnose the OBDII code B1578 in my Ford vehicle?

To diagnose the OBDII code B1578 in your Ford vehicle, you can use an OBDII scanner to read the fault code and perform a visual inspection of the lighting system components for any visible damage or wiring issues.

4. What are some possible repair tips for fixing the OBDII code B1578 in a Ford vehicle?

Some repair tips for fixing the OBDII code B1578 in a Ford vehicle include checking and repairing any damaged wiring, replacing faulty lighting system components, and ensuring proper grounding of the lamp park input circuit.

5. Is it safe to continue driving my Ford vehicle with the OBDII code B1578 illuminated?

It is not recommended to continue driving your Ford vehicle with the OBDII code B1578 illuminated, as it indicates a potential issue with the exterior lighting system, which could compromise safety on the road.

6. Can the OBDII code B1578 be reset in a Ford vehicle?

Yes, the OBDII code B1578 can be reset in a Ford vehicle using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes to clear the code.

7. Will the OBDII code B1578 in a Ford vehicle cause any other problems if left unrepaired?

If left unrepaired, the OBDII code B1578 in a Ford vehicle may cause further electrical issues within the lighting system and potentially lead to safety hazards or failures during operation.

8. How much does it typically cost to repair the OBDII code B1578 in a Ford vehicle?

The cost to repair the OBDII code B1578 in a Ford vehicle can vary depending on the extent of the damage and the specific components that need to be replaced, but it may range from a few hundred to a thousand dollars.

9. Can I fix the OBDII code B1578 in my Ford vehicle myself, or should I take it to a professional mechanic?

If you have experience with automotive electrical systems and wiring, you may attempt to fix the OBDII code B1578 in your Ford vehicle yourself. However, if you are unsure or inexperienced, it is best to seek the help of a professional mechanic.

10. How long does it take to repair the OBDII code B1578 in a Ford vehicle?

The time it takes to repair the OBDII code B1578 in a Ford vehicle can vary depending on the complexity of the issue and the availability of parts. In general, it may take a few hours to a full day for a mechanic to diagnose and fix the problem.