P0012: Intake camshaft timing behind target (bank 1)
Intake camshaft timing over-retarded (bank 1)
Severity: Inspect soon
P0012 means the bank 1 intake camshaft is not where the engine computer wants it. The engine usually keeps running with reduced performance or rough running; OBD rules treat it as an emissions fault and Ford's owner guidance for a steady light is to have it serviced, so get it inspected soon.
It gets more serious if:
- Stop: The check engine light starts flashing (misfire heavy enough to damage the catalytic converter). Avoid further driving and get it checked.
P0012 in short
P0012 means the bank 1 intake camshaft is more retarded than the engine computer commanded. Low or wrong-grade oil is the first thing to check, because the phaser falls back toward retard without oil pressure, then the oil control solenoid. It is usually drivable short-term, but get it inspected soon.
Variable valve timing uses engine oil, steered by a solenoid, to rotate a phaser on the camshaft. The engine computer sets a target cam angle and reads the actual angle from the camshaft sensor.
P0012 sets when the bank 1 intake cam stays behind (retarded from) its target. On the ASE reference design the phaser defaults to fully retarded when oil pressure is low, so oil level and condition come first, then a sticking or failed solenoid, a sticking phaser, or timing drive wear.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Low oil level, old or sludged oil, or the wrong viscosity
Common general cause- Why it ranks here
- The phasers are moved by oil pressure, and on the ASE reference design the actuator falls back to fully retarded when there is little or no oil pressure. Ford's first step for P0012 on the 2019-2020 F-150 5.0L is to correct the oil level.
- What would change this
- Rises if the dipstick is low, the oil is overdue or dark and thick, or the grade differs from the owner's manual; falls if the oil is full, fresh and correct.
Cause 2: Oil control (VVT) solenoid stuck by debris or a blocked screen
Common general cause- Why it ranks here
- Debris and sludge can block the solenoid's inlet screen or stick its valve. Ford issued a service message for P0011, P0012 and related codes on many 2017 models from exactly this.
- What would change this
- Rises if the cam angle does not follow commands but recovers after the solenoid is cycled or the screen is cleaned; falls if it responds normally.
Cause 3: Failed VVT solenoid or its wiring
Common general cause- Why it ranks here
- A solenoid with a failed winding or wiring cannot steer oil to the phaser. An electrical fault usually sets its own circuit code too.
- What would change this
- Rises if a solenoid circuit code is stored, the resistance is out of spec or it does not click when commanded.
Cause 4: Sticking cam phaser (worn lock pin or broken spring)
Possible — needs testing- Why it ranks here
- OBD rules name stuck phasers and broken return springs as failure modes the monitor must catch, but a phaser is usually only blamed after oil and the solenoid check out.
- What would change this
- Rises if the solenoid works but the cam angle still lags or does not move, especially with a brief rattle at cold start.
Cause 5: Camshaft position sensor or wiring fault
Possible — needs testing- Why it ranks here
- The computer judges cam position from this sensor, so a bad signal can look like a timing error, though a failed sensor usually sets its own code.
- What would change this
- Rises if a cam sensor circuit code is also stored or the signal drops out on a scope.
Cause 6: Stretched timing chain or jumped belt
Possible — needs testing- Why it ranks here
- Base cam timing only moves if a chain stretches or a belt skips. It is not the usual cause of this code, so treat it as something to test for, not assume.
- What would change this
- Rises with crank/cam correlation codes (P0016/P0017), a timing-area rattle or high mileage; a scope check of crank and cam signals confirms it.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: With the engine off on level ground, check the oil level and condition, and confirm the oil grade matches the owner's manual.
IfOil is low, overdue, sludgy or the wrong viscosity
It meansCorrect the oil first, clear the code and drive; many VVT codes return no further.
Points to: Low oil level, old or sludged oil, or the wrong viscosity
IfOil is full, fresh and the right grade
It meansLook at what the cam is actually doing.
Step 2: With the engine warm, watch desired versus actual intake cam angle on a scan tool while varying engine speed.
IfActual angle follows desired closely
It meansThe fault is intermittent; check for other codes and recheck after the next drive.
IfActual angle lags, overshoots or does not move
It meansOil control or the phaser is not responding.
Step 3: Command the intake oil control solenoid on and off with a bidirectional scan tool and watch the cam angle; if the manufacturer allows, cycle it several times to try to clear debris.
Warning:The engine runs during this test. Keep hands, hair and clothing away from belts and the cooling fan, and do it in a ventilated space.
IfCam angle responds and the fault clears after cycling
It meansDebris was sticking the valve.
Points to: Oil control (VVT) solenoid stuck by debris or a blocked screen
IfNo click and no change in cam angle
It meansSolenoid or wiring fault.
IfSolenoid clicks but cam angle barely changes
It meansOil is not reaching the phaser or the phaser is stuck.
Step 4: Remove the oil control solenoid and inspect it and any inlet screen for sludge or debris.
Warning:Let the engine cool first; oil and engine parts stay hot enough to burn for a long time after shutdown.
IfScreen or valve is blocked with debris
It meansClean or replace as the service information says, and change the oil.
Points to: Oil control (VVT) solenoid stuck by debris or a blocked screen
IfClean
It meansPhaser or timing drive is suspect.
Step 5: Have a shop compare crank and cam sensor signals on a scope (or the manufacturer's correlation data) and check base timing.
Warning:Timing checks may need covers removed and special tools; incorrect work can wreck the engine. Leave this to a shop.
IfCam signal is offset from crank at rest
It meansThe timing drive has stretched or jumped. Timing drive wear is a known cause of crank/cam correlation codes on some engines.
IfBase timing is correct but the cam will not move
It meansThe phaser is sticking.
Points to: Sticking cam phaser (worn lock pin or broken spring)
Symptoms
- Rough idle
- Reduced power or poor fuel economy
- Hard starting or stalling Gets more serious: stop and have it checked.
- Rattle from the timing area, especially at cold start Gets more serious: stop and have it checked.
- Check engine light flashing Gets more serious: stop and have it checked.
Compare with: Rough idle with the check engine light on, Check engine light with loss of power
How to fix
Step 1: Check the oil level and top it up to the full mark with the grade listed in your owner's manual.
Warning:Engine off and on level ground; wait a few minutes for oil to drain back.
Step 2: If the oil is overdue or the wrong grade, change the oil and filter with the specified oil, clear the code and drive normally to see whether it returns.
Warning:Let the engine cool before draining; hot oil burns. Support the car on ramps or stands, never just a jack.
Step 3: Record codes and freeze-frame data before clearing, so a returning code can be compared.
On your vehicle
FordYour car
2017
Supported by vehicle dataFor P0012 on 2017 Ford and Lincoln models, Ford's special service message says to cycle the VCT solenoid ten times with a scan tool to clear debris before replacing it.
NHTSA owner complaints mentioning P0012: 28. That shows what owners reported, not how often a cause sets the code.
2019–2020 · F-150 · 5.0L V8
Supported by vehicle dataOn the 5.0L, Ford says to correct the oil level first for P0012 and phaser noise, then replace only the VCT solenoid for the code present.
SSM 46450Status unverified
Ford SSM 46450: MIL with VCT codes from debris sticking the VCT solenoid
2017edge, escape, explorer, f-150, fusion, mustang, transit · issued · NHTSA 10099458
Before diagnosing or replacing a VCT solenoid for P0011, P0012, P0014-P0019, P0021, P0022, P0024 or P0025, cycle the solenoid 10 times with pinpoint test HK11 to clear debris. NHTSA lists most 2017 Ford and Lincoln models; only a selection of models is listed here.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
SSM 49583Status unverified
Ford SSM 49583: P0011, P0012, P0021, P0022 and phaser noise, F-150 5.0L
2019–2020f-150 · 5.0L V8 · issued · NHTSA 10187998
On 2019-2020 F-150 with the 5.0L, these cam timing codes may come with noise near the front of the valve covers from the intake phasers. Verify and correct the oil level; if it persists, replace only the VCT solenoid(s) for the codes present, then continue normal diagnosis.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
ToyotaYour car
2005–2007 · Corolla
Supported by vehicle dataToyota has a bulletin covering P0011, P0012 or P0016 on the Corolla. The summary does not give the repair, so ask a dealer to check bulletin 00507.
2005–2007 · Corolla Matrix
Supported by vehicle dataToyota has a bulletin covering P0011, P0012 or P0016 on the Matrix. The summary does not give the repair, so ask a dealer to check bulletin 00507.
00507Status unverified
Toyota 00507: MIL with P0011, P0012 or P0016
2005–2007corolla, corolla-matrix · issued · NHTSA 10021407
Covers a check engine light with P0011, P0012 or P0016 on 2005-2007 Corolla and Matrix. NHTSA's summary does not give the cause or repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
P0012 questions
Can bad or low oil cause P0012?
Yes, and it is the first thing to check. The phasers that move the camshafts are driven by engine oil, so low level, sludge or the wrong viscosity can make the cam miss its target. Top up or change to the grade in your owner's manual and see if the code returns.
Is it safe to drive with P0012?
Usually for a short while, with care. Expect reduced power or rough running. Get it inspected soon, and stop driving if the light flashes, the engine starts rattling or knocking, or it stalls.
What is the difference between P0011 and P0012?
Both concern the bank 1 intake cam. P0011 means it is more advanced than commanded or slow to respond; P0012 means it is stuck behind its target. Both start with checking the oil and the oil control solenoid.
Sources and review
- Cal. Code Regs. tit. 13, § 1968.2 - Malfunction and Diagnostic System Requirements (OBD II)
- 2001 Lincoln Continental Owner's Guide - Warning lights (Check engine)
- Variable Valve Timing
- ASE L1 Advanced Engine Performance Specialist Test: Composite Vehicle Type 4 Reference Booklet
- Ford SSM 49583: P0011, P0012, P0021, P0022 and phaser noise, 2019-2020 F-150 5.0L
- Ford Special Service Message 46450: MIL with VCT codes (P0011, P0014, P0016, P0017 and others) from debris sticking the VCT solenoid
- ASE A1 study guide: VVT phaser diagnostics
- Toyota 00507: MIL with P0011, P0012 or P0016
- NHTSA ODI consumer complaints flat files
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
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