Engine-CodesInfiniti – P0078 Infiniti

P0078 Infiniti Code - Exhaust Valve Timing Control Magnet Retarder Circuit Bank 1

Quick Answer

The P0078 code for Infiniti vehicles refers to a problem with the Exhaust Valve Timing Control (EVTC) magnet retarder circuit on Bank 1. Common causes include Faulty EVTC Magnet Retarder: The magnet itself may be faulty, causing timing control issues, Wiring Issues: Damaged or corroded wiring in the circuit can disrupt the signal between the ECM and the EVTC magnet, ECM Malfunction: A malfunction in the engine control module can prevent proper communication with the EVTC magnet. 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
P0078 Infiniti indicates Exhaust Valve Timing Control Magnet Retarder Circuit Bank 1.
Common causes
Common causes include Faulty EVTC Magnet Retarder: The magnet itself may be faulty, causing timing control issues, Wiring Issues: Damaged or corroded wiring in the circuit can disrupt the signal between the ECM and the EVTC magnet, ECM Malfunction: A malfunction in the engine control module can prevent proper communication with the EVTC magnet.
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.
Table of contents Created and updated by William Orellana on Sep 09, 2024
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Code P0078 Infiniti Description

The P0078 code for Infiniti vehicles refers to a problem with the Exhaust Valve Timing Control (EVTC) magnet retarder circuit on Bank 1. This circuit is responsible for controlling the timing of the exhaust valves, which play a crucial role in the engine's performance and emissions. When this code is triggered, it indicates that there is an issue with the electrical circuit that controls the EVTC magnet, leading to potential timing control problems.

OBDII Code P0078 Infiniti - Exhaust Valve Timing Control Magnet Retarder Circuit Bank 1
P0078 Infiniti Code - Exhaust Valve Timing Control Magnet Retarder Circuit Bank 1

Common Causes of P0078 Infiniti

  1. Faulty EVTC Magnet Retarder: The magnet itself may be faulty, causing timing control issues.
  2. Wiring Issues: Damaged or corroded wiring in the circuit can disrupt the signal between the ECM and the EVTC magnet.
  3. ECM Malfunction: A malfunction in the engine control module can prevent proper communication with the EVTC magnet.
  4. Poor Electrical Connection: Loose or poor electrical connections can lead to intermittent signal transmission.
  5. Sensor Issues: Problems with sensors that provide input to the ECM for timing control can trigger the P0078 code.

Symptoms of P0078 Infiniti

  1. Check Engine Light: The most common symptom associated with the P0078 code is the illumination of the Check Engine Light on the dashboard.
  2. Reduced Power: The vehicle may experience a loss of power or acceleration due to incorrect timing control.
  3. Rough Idling: Engine may idle roughly or inconsistently, indicating timing issues.
  4. Increased Emissions: The vehicle may produce higher emissions due to improper timing control.
  5. Engine Misfires: Misfires or hesitation during acceleration can occur as a result of the timing control problem.

How to Fix P0078 Infiniti

  1. Diagnostic Scan: Begin by using an OBD-II scanner to retrieve the specific code and identify the source of the issue.
  2. Check Wiring: Inspect the wiring harness for any damage, corrosion, or loose connections. Repair or replace as necessary.
  3. Test EVTC Magnet: Test the EVTC magnet to ensure it is functioning correctly. Replace if defective.
  4. Check ECM: Verify the functionality of the engine control module and address any malfunctions or faults.
  5. Clear Codes: After repairs are completed, clear the code and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0078 Infiniti

The cost of repairing the P0078 code on an Infiniti vehicle can vary depending on the specific cause of the issue and the labor rates in your area. On average, the repair costs for this issue can range from $200 to $500. This estimate includes the cost of parts such as the EVTC magnet, wiring harness, and any necessary diagnostic tests. It's important to note that labor rates at auto repair shops can vary significantly, so it's recommended to obtain quotes from multiple shops to get an accurate estimate for your specific situation. Additionally, the cost may be higher if additional components need to be replaced or if there are underlying issues that require further investigation.

When is the Code Detected?

An improper voltage is sent to the Engine Control Module (ECM) through exhaust valve timing control magnet retarder.

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Information for Specific Infiniti Models

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.

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