P0021 – Meaning, Causes, Symptoms, & Fixes

Code P0021 Definition

Camshaft Position “A” – Timing Over -Advanced or System Performance (Bank 2)

What Does P0021 Mean?

Variable Valve/Camshaft Timing in the internal combustion engine control the intake and exhaust gases in and out of the gas combustion chamber. You want to vary the way your engine operates at different points of the engine’s rev range. Varying the different valve events: valve timing, valve duration, and valve lift allows the ECU to constantly make a call to the most power, the best mpg, and the lowest emissions. The different pistons that pump up and down leave the exhaust valves with the maximum air space that the engine can take in fuel and air to give you maximum power. When trouble code P0021 is set, it means that camshaft position “A” in Bank 2 is more advanced than the ECM has told it to be.

P0021 Symptoms

  • Check Engine Light
  • Hard start of the engine
  • Rough running engine
  • Increased fuel economy
  • Failed emissions test

P0021 Causes

  • The exhaust shaft has advanced too much when the ECM has told it to slow down to a lower timing level.
  • Camshaft variable timing solenoid failure
  • Camshaft phaser is seized in the advanced position
  • Continuous oil flow to Variable Camshaft Timing chamber
  • Viscosity of oil is too thick or too thin

Code P0021 Severity – Moderate   

The engine may have erratic and other engine problems that could affect driving and fuel economy may decrease due to increase fuel consumption. As for any Diagnostic Trouble Code it should be repaired as soon as possible for no internal damage.

Code P0021 Common Diagnosis Mistakes

Replacing sensors or components without any indication of a problem with the sensors or components.

P0021 Diagnosis

  • Tools Needed to Diagnose:
    • FIXD
    • Car specific service manual

Difficulty of Diagnosis and Repair – (1-4)

  1. Visually inspect the connector, wiring, or valve problems with the Oil Control Valve for Bank 2 exhaust valve.
  2. Check the engine’s oil level and viscosity to see if they are correct.
  3. Check the live freeze frame data
    1. Monitor the timing of the data and disconnect the Oil Control Valve to the exhaust camshaft. If there is a change it means that the valve is working correctly and there is an electrical problem within the ECM.
  4. Find your vehicle specific service manual and follow the pinpoint tests to repair them as needed.

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Comments 9

Lee C Pelzer

September 15, 2018

Alright very good information

Denny Christensen

December 16, 2018

Love this site very helpful

FIXD Marketing

December 17, 2018

Thanks Denny! Glad we can help!



June 4, 2019

I have a Ford expedition 2007 5.4 engine has codes p0021,p0011 plus p0240 truck runs fine but sometimes when i try to accelerate quick truck stalls any ideas?thanks in advance.

jimmy Tinsley

June 29, 2019

Victor I have this same problem what did you do to fix it ?

Peter Wallin

September 13, 2019

Getting yearly check up next week on 2004 Cayenne, will ask them to check this issue

Thank you


September 15, 2019

I have the code p0021,I have recently changed out both camshaft sensors bank 1 and 2,the crankshaft position sensor. It will start and drive without any problems, but when I shut it off and try and start it again, it will crank but won’t start.ill try again after an hr and it will start right up and drive. This is a 2003 Infiniti g35 sedan


September 15, 2019

I have a 2003 Infiniti g35 sedan. A code p0021 is showing on my ob2 reader. The problem is it will cold start and drive with no issues,but when I turn it off and try and restart it will only crank and not start. I’ll try again in about an hour and it starts right up and drives fine. I just replaced camshaft sensors bank 1 and 2 and the crankshaft position sensor as well


October 3, 2019

Recently got an oil change on a 2004 Nissan quest. Didn’t have this issue before hand. It appears they put 5 quarts of oil in, but it says it only takes 4.2. couple this be the cause and if so, would taking some out fix it?

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