Engine-Codes - Generic - B1578

B1578 - Lamp Park Input Circuit Short To Ground

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3  What is this?
Table of contents

B1578 Possible Causes

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

How is the B1578 code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

What is the cost to diagnose the B1578 code

Labor: 1.0

The cost to diagnose the B1578 code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.
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Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

B1578 Meaning

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.

More Information

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Information for specific makes

  • B1578 CHRYSLER Audio Antenna Circuit Resistance Below Threshold
  • B1578 DODGE Audio Antenna Circuit Resistance Below Threshold
  • B1578 FORD Lamp Park Input Circuit Short To Ground
  • B1578 JEEP Audio Antenna Circuit Resistance Below Threshold
  • B1578 LINCOLN Lamp Park Input Circuit Short To Ground
  • B1578 MERCURY Lamp Park Input Circuit Short To Ground
  • B1578 RAM Audio Antenna Circuit Resistance Below Threshold

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