Code P1386 – Variable Cam Timing Over-Advanced, Bank 2

Possible Causes

NOTE: The listed causes may not be a complete list of all potential issues, and other causes may be present.

1. Incorrectly adjusted camshaft timing: Improper timing adjustment can lead to reduced engine efficiency and increased pollutant emissions.
2. Continuous oil flow to the VCT piston chamber: Excessive oil flow can disrupt camshaft timing management, resulting in poor engine performance.
3. VCT solenoid valve stuck in open position: If the solenoid valve remains permanently open, it prevents the timing adjustment mechanism from functioning correctly, which can cause timing discrepancies in the camshaft.
4. Blockage of the camshaft advance mechanism (VCT unit): A blockage in the mechanism can prevent precise timing adjustment, leading to engine performance issues.

Problem Description

The variable camshaft timing solenoid only affects the intake camshaft timing, adjusting its position based on driving conditions. It uses engine oil to activate a helical splined actuator that allows for a rotation of 50 degrees. This action optimizes engine efficiency, fuel consumption, and emissions by adjusting the fuel injection timing according to the engine’s needs.

The component monitoring system (CCM) is responsible for detecting any excessive delay in camshaft timing. If the timing exceeds a calibrated maximum value or remains in a retarded position, the system detects a malfunction and triggers an error code.

How to Fix the Problem

1. Check the possible causes listed above.
2. Visually inspect the wiring harness and related connectors, as faulty or damaged connectors can cause signal issues.
3. Inspect the components for any failures, including the solenoid valves and the VCT unit mechanism. If any of these components are defective, they may need to be replaced.
4. Check the oil pressure and flow to ensure that engine oil is properly delivered to the timing system.

Possible Symptoms

• Check engine light on (or engine warning light soon to come on)
• Loss of engine power
• Poor engine performance, especially during startup or acceleration
• Increased fuel consumption
• Unusual engine noise due to incorrect camshaft timing

Additional Tips

• If the problem persists after inspecting and cleaning the components, it may be necessary to replace parts such as the timing solenoid or the VCT solenoid valve.
• A detailed electronic diagnosis using an OBD2 diagnostic tool can provide additional information about the exact nature of the problem and facilitate the repair process.