P0021 on Mazda: How to Diagnose & Fix
Intake Camshaft Position Timing - Over-Advanced (Bank 2)
1 Mazda model · 1 documented issue · 1 critical · $400-$1,200 repair
P0021 on Mazda by model: symptoms, diagnosis and fix
The exhaust-side VVT actuator (cam phaser) fails due to oil sludge and wear, causing timing codes and engine rattle. The actuator solenoid can also stick, leading to incorrect valve timing. Oil change neglect accelerates failure. Common on both MZR and early SkyActiv 2.5L engines.
Common Symptoms
- Rattling noise on cold start (chain slap)
- Check engine light with P0012 or P0022 cam timing codes
- Rough idle and stalling at stop lights
- Reduced power and poor fuel economy
How to Fix
Replace VVT actuator/cam phaser assembly and VVT solenoid. Use Mazda-spec 0W-20 full synthetic oil and replace at 5,000-mile intervals to prevent sludge. Check timing chain stretch while servicing.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Mazda genuine electric intake VVT actuator PE01-12-4X0BOEMMazda PE01-12-4X0B
Electric intake VVT actuator after the bulletin PID test confirms actuator failure Fitment/availability: The inspected direct page identifies genuine Mazda PE01-12-4X0B as the actuator and lists 2014-2017 Mazda6 2.5L applications.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Owner tips & cautions
- TipUse full synthetic 0W-20 (Mazda spec) and change oil every 5,000 miles max - Mazda6Club.com VVT thread
- TipInspect timing chain stretch when replacing VVT - may need chain replacement at high mileage
P0021 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0021 mean on a Mazda?
P0021 stands for "Intake Camshaft Position Timing - Over-Advanced (Bank 2)." P0021 means the engine computer detected that the intake camshaft on bank 2 is timed too far advanced and won't return to its commanded position. Most modern engines use variable valve timing (VVT), where an oil-pressure-driven actuator rotates the camshaft to optimize power and efficiency; the PCM compares the camshaft's actual position to its target. When the cam stays over-advanced beyond an acceptable limit, this code sets. Bank 2 refers to the side of the engine that does not contain cylinder number one. You may notice rough idle, reduced performance, or lower fuel economy. On Mazda it is documented across 1 model: Mazda6.
What are the most common causes of P0021?
The most common causes of P0021 are: Dirty or low engine oil restricting the VVT system, Stuck or failed camshaft oil control valve (VVT solenoid) on bank 2, Clogged VVT solenoid screen or oil passage, Faulty camshaft position actuator / phaser, Wiring or connector fault at the VVT solenoid, Camshaft or crankshaft position sensor problems, Worn timing chain, guides, or stretched chain altering cam timing. The specific cause varies by vehicle.
How much does it cost to fix P0021 on a Mazda?
Published repair estimates on Mazda range from $400 to $1,200 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0021 on a different make?
View P0021 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.