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AutoCodes - Generic - B2578

B2578 Code - Right Front Turn Signal Monitor Circuit

- Code Popularity: 2,374 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC B2578?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Right Front Turn Relay
  • Right Front Turn Relay harness is open or shorted
  • Right Front Turn Relay circuit poor electrical connection
  • Faulty Body Control Module (BCM)
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How to Fix the DTC B2578?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B2578 code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

What are Code Possible Symptoms?

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

Code B2578 Description

The Body Control Module (BCM) monitors the Right Front Turn Signal circuit in order to determine the status of the turn signal switch. If the BCM detects an oscillating voltage on the RH turn signal monitor circuit, the BCM interprets this as a RF turn signal ON request from the turn signal switch. The BCM will then de-energize the RH DRL relay, which will disable the RF turn signal lamp (which is ON for the DRL), this allows the RF turn signal to flash. If the BCM does not detect an oscillating voltage on the RH turn signal monitor circuit, the BCM interprets this as the RF turn signal being OFF. The BCM will then energize the RH DRL relay and continue normal DRL operation. The BCM monitors the RH turn signal monitor circuit and determines how long voltage is applied. If the voltage is applied for longer than expected, a malfunction is present and a DTC will set.

OBDII Code B2578 - Right Front Turn Signal Monitor Circuit - AutoCodes.com
B2578 Code - Right Front Turn Signal Monitor Circuit

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