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P0012 OBD Fault Code: Signs, Causes & How to Fix

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Last Updated on: 21st November 2023, 02:58 am

P0012 OBD fault code stands for: Intake Camshaft Position Timing- Over-Retarded (Bank 1)

Quick Summary
  • The P0012 code, typically a moderate issue in severity, indicates a problem with the camshaft timing in a vehicle’s engine.
  • This issue can lead to decreased engine performance and efficiency, with symptoms like rough idling and increased fuel consumption.
  • While a vehicle with this code can still be driven, it’s crucial to address it quickly. Ignoring it could result in worsening issues and potential damage to the engine, making repair essential to prevent more severe problems.

This fault code is related to the engine’s timing mechanisms, specifically pointing to irregularities in the camshaft position.

In this article, we’ll go deeper into what this code means, its causes, symptoms, and potential fixes.

What the P0012 Code Means

The P0012 code is an OBD-II generic code indicating that the Engine Control Module (ECM) has detected the intake camshaft in bank 1 is positioned more retarded (delayed) than what the ECM has commanded.

In simpler terms, this means the timing of the camshaft is not aligned as per the engine’s predetermined specifications.

This misalignment can adversely affect engine performance and efficiency.

How Serious Is It?

Based on our OBD Fault Code Severity Rating scale, a P0012 code is typically classified as a moderate issue.

  1. Drivability: While a vehicle with this code might still be operable, its engine performance may be compromised. This can manifest as reduced power, rough idling, or difficulty in starting the engine.
  2. Potential for Worsening Issues: If the issue underlying the P0012 code is not addressed promptly, it can lead to more significant engine problems. For example, continuous operation with improper camshaft timing can cause strain to other engine components, increasing wear and potentially leading to more costly repairs.
  3. Risk of Damage: Prolonged driving with this issue can potentially cause further damage to the engine, especially if it involves critical components like the timing chain or VVT/VCT system.

Therefore, while the vehicle can still be driven for a short time, it is advisable to have it repaired as soon as possible to prevent further damage and to maintain optimal engine performance and efficiency.

It’s important to note that the severity can escalate if the issue is ignored over time, potentially moving towards the “severe” category in extreme cases.

OBD Fault Code Severity Rating
  • minor (non-issue or doesn’t need fixing in any immediate manner, can still be driven)
  • moderate (can be driven still but needs repairing asap, symptoms may worsen or could lead to damage if left unfixed)
  • severe (do not drive or start the engine)

Technical Overview

  • Variable Valve Timing (VVT) and Variable Camshaft Timing (VCT): A P0012 code is often associated with these systems. VVT and VCT are technologies designed to improve engine performance and fuel efficiency by altering the timing of valve opening and closing. If these systems malfunction, it can lead to the P0012 code.
  • Bank 1: This refers to the side of the engine that houses the first cylinder. In a V-shaped engine, bank 1 is typically located on the side of the engine closest to the front of the vehicle.


Several factors can trigger the P0012 code, including the following.

  1. Faulty camshaft phaser: This component adjusts the timing of the camshaft. If it’s defective, timing cannot be correctly adjusted.
  2. Dirty or low-quality engine oil: Oil quality is crucial for the proper functioning of VVT/VCT systems. Dirty or degraded oil can lead to poor lubrication and mechanical hindrances.
  3. Sensor malfunction: Faulty readings from the camshaft or crankshaft sensors can result in incorrect timing adjustments.
  4. Timing chain issues: A stretched or worn timing chain can also cause timing discrepancies.


The symptoms accompanying a P0012 code may vary but commonly include.

  • Decreased engine performance.
  • Increased fuel consumption.
  • A rough engine idle.
  • The “Check Engine” light illuminated on the dashboard.
  • In some cases, the engine may not start.

Diagnosing & How to Fix

Addressing a P0012 code involves a series of steps:

  1. Diagnostic scanning: Use an OBD-II scanner to confirm the presence of the P0012 code and check for any other related codes.
  2. Visual inspection: Examine the timing chain and related components for wear or damage.
  3. Oil quality check: Ensure the engine oil is at the right level and quality. Change if necessary.
  4. Sensor testing: Test the camshaft and crankshaft position sensors for proper functioning.
  5. Component replacement: Depending on the diagnosis, replace faulty components like the camshaft phaser, sensors, or timing chain.


The P0012 code is a clear indicator of timing issues in the engine, particularly relating to the camshaft position in bank 1.

Regular maintenance, including oil changes and timely component checks, can help prevent such problems from arising.

  • Andy Lewin

    Andy Lewin is a senior mechanic, ASE qualified master technician, and an experienced automotive engineer. He's passionate about serving the automotive community with the highest-quality and trustworthy information on all things automotive. He loves to write about car repairs, maintenance, car modifications and tuning, faults, and much more.

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