Engine-Codes - Mercedes-Benz - P0412 Mercedes-Benz

P0412 Mercedes-Benz Code - Secondary Air Injection System Switching Valve 'A' Circuit Malfunction

- Code Popularity: 11,948 Views
- Repair Importance Level: 2/3
- Repair Difficulty Level: 2/3
Table of contents
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What are the Possible Causes of the DTC P0412 Mercedes-Benz?

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 Air Pump inoperative
  • Air bypass solenoid harness is open or shorted
  • Air bypass solenoid circuit poor electrical connection
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How to Fix the DTC P0412 Mercedes-Benz?

Check 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 pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0412 Mercedes-Benz code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

When is the Code Detected?

The DTC P0412 is detected the the AIR vacuum control solenoid circuit not operating as desired by the PCM.

What are Code Possible Symptoms?

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

What Does the P0412 Mercedes-Benz Code Mean?

An air pump is used on the vehicle to lower tail pipe emissions on start-up. The Powertrain Control Module (PCM) grounds the Air pump relay control circuit which energizes the Air pump. The PCM also grounds the Air combination valve vacuum control solenoid circuit, which energizes the Air vacuum control solenoid. Vacuum is then applied to both Air combination valve diaphragms which opens the shut off valves. The PCM enables both circuits simultaneously when Air system operations id desired. When the AIR system is active, then Air pump forces fresh air into the exhaust stream in order to accelerate catalyst operation. The AIR combination valves replace the conventional check valves. When the AIR system is inactive the shut off valves prevent air flow in either direction.

P0412 Mercedes-Benz Code - Secondary Air Injection System Switching Valve 'A' Circuit Malfunction

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