What is the P0012 trouble code?
P0012 trouble code, applicable to all car manufacturers, means “A Camshaft Position – Timing Over-Retarded (Bank 1)“.
Background Information: The camshaft controls the opening and closing of the valves. In a variable valve timing system, the electronic camshaft control valve (or oil control valve, OCV) adjusts the camshaft angle by changing the oil pressure to the camshaft adjuster (mechanical type) according to instructions from the engine control module (ECM) to ensure that the valves open and close at the optimal time. The causes of the P0012 fault include improper setting of the A intake/left/front camshaft timing, and mechanical jamming of the camshaft retardation mechanism. In short, it refers to a timing issue. The “A” camshaft must be the “intake,” “left,” or “front” camshaft, determined by viewing from the driver’s position to determine left/right and front/rear. Bank 1 refers to the cylinder bank that includes cylinder 1, and Bank 2 is the bank opposite to Bank 1.
Symptoms of P0012 Error Code
- Unstable engine operation
- Starting difficulties
- Reduced power
- Increased fuel consumption
- Check engine light on the dashboard
- Unusual noises from the engine compartment
Main Causes of P0012 Error Code
- Contamination or failure of the VVT solenoid valve
- Low or dirty engine oil
- VVT system malfunction (electrical or mechanical failure)
- Displacement or stretching of the timing chain
- Mechanical damage to the camshaft or timing components
P0012 Error Code in Different Vehicles
Ford P0012: In Ford EcoBoost engines, the error may occur due to VVT solenoid valve contamination or low oil pressure. The problem is usually solved by changing the oil and cleaning the solenoid valve.
BMW P0012: BMW engines (especially the N52/N54 series) have problems with the phase shifter. Replacing the VANOS system or flushing the lines is usually required.
Toyota P0012: The P0012 fault code in Toyota models may be caused by a stretched timing chain, especially at high mileage. Sometimes replacing the tensioner or the chain itself helps.
Mazda P0012: Models with SkyActiv engines are prone to this error due to unstable VVT operation with old engine oil. Regular oil changes are crucial.
Hyundai P0012: In Hyundai/Kia engines, the error may be due to clogged mesh in the VVT valve. An effective solution is to replace the valve and flush the oil system.
How to Diagnose P0012 Error Code?
Step 1: Read the error code using an OBD2 scanner
Step 2: Check the engine oil level and condition
Step 3: Visually inspect the timing chain or timing belt
Step 4: Check the operation of the VVT solenoid valve
Step 5: Check the signal of the camshaft position sensor
Possible Causes and Diagnostic Methods
| Possible Cause | How to Check？ |
|---|---|
| Low oil level | Check the oil level and condition |
| Dirty or faulty VVT solenoid valve | Disassemble, clean, or replace |
| Camshaft position sensor malfunction | Test with a multimeter and oscilloscope |
| Timing phase violation | Check timing phase markings and chain or belt condition |
| Wiring fault or VVT connector issue | Check and test for open/short circuits |
Tools needed: OBD2 scanner, multimeter, mechanical or digital pressure gauge, a set of hand tools (screwdrivers, wrenches), oil passage or solenoid valve cleaner
How to fix P0012 error code? (Solutions to the problem)
Simple troubleshooting methods
- Check and top up engine oil
- If the oil is dirty or old, replace the oil and filter.
- Clean or replace the VVT solenoid valve.
- After resolving the cause, use a scanner to reset the error.
In-depth diagnostic and repair solutions
- Replace the tensioner chain or timing belt
- Check and replace the hydraulic tensioner
- Testing and replacement of camshaft/crankshaft position sensors
- Check the ECU and its firmware for errors
Troubleshooting by symptoms
| Symptom | Possible solution |
|---|---|
| Increased fuel consumption | Check timing phase, replace solenoid valve or engine oil |
| Engine misfire | VVT system diagnosis, camshaft inspection |
| Difficulty starting | Oil change, phase sensor check |
| Error returns after reset | Check the entire VVT and timing system |
P0012 Frequently Asked Questions
Can I drive a car with error code P0012?
Not recommended. Engine operation may be unstable, potentially leading to power loss and increased fuel consumption, increasing the risk of further damage.
What happens if I ignore error P0012?
Ignoring it can lead to serious engine damage, including failure of the phase shifter, sensors, or even the timing chain.
Is it possible to reset the P0012 code without fixing the problem?
The fault code can be temporarily reset using an OBD diagnostic tool or by disconnecting the battery, but the error will reappear if the fault is not eliminated.
Can error P0012 occur due to poor engine oil?
Yes. Dirty or old oil can interfere with the VVT system and potentially cause malfunctions.
When error P0012 occurs, do I need to replace the timing chain?
Not always, but if the chain is stretched or the phase markings are off, replacement may be necessary to correct the root cause of the error.
Related OBD2 Errors:
P0010 – A Camshaft Position Actuator Circuit/Open (Bank 1))
P0011 – A Camshaft Position – Timing Over-Advanced or System Performance (Bank 1)
P0022 – A Camshaft Position – Timing Over-Retarded (Bank 2)
Important! If the P0012 error is not corrected promptly, it can cause serious damage to the engine, including timing wear and a shortened engine lifespan. Regular oil changes, VVT system diagnostics, and timely maintenance can help prevent P0012 errors and extend engine life.