If your OBD-II scanner displays P0012, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected that the “A” camshaft on Bank 1 is more retarded than commanded or remains in a retarded position for too long.
On most engines, the “A” camshaft is the intake camshaft, while Bank 1 is the side of the engine containing cylinder number one. The intake camshaft is part of the variable valve timing system, which adjusts valve timing to improve power, fuel economy, idle quality and emissions.
P0012 is commonly caused by:
- Low engine oil
- Dirty or incorrect engine oil
- A sticking variable valve timing solenoid
- Restricted oil passages
- A worn camshaft phaser
- Low engine oil pressure
- A stretched timing chain
- Incorrect mechanical timing
- Damaged actuator wiring
Unlike P0010, which primarily identifies an electrical problem in the actuator circuit, P0012 usually indicates that the camshaft is not physically reaching the position commanded by the ECM.
The problem may be as simple as overdue engine oil or as serious as a stretched timing chain. Prompt diagnosis can help prevent poor performance and possible engine damage.
Looking for more diagnostic resources? Browse our complete OBD-II libraries:
- Complete OBD-II Code Library: https://my.prostreetonline.com/dtc-obdii/
- Body (B) Codes: https://my.prostreetonline.com/dtc-doctor/b-code-obd-ii-codes/
- Chassis (C) Codes: https://my.prostreetonline.com/dtc-doctor/c-code-obd-ii-codes/
P0012 Quick Facts
| Item | Information |
|---|---|
| OBD-II code | P0012 |
| Official description | “A” Camshaft Position Timing Over-Retarded Bank 1 |
| Category | Powertrain |
| System | Variable valve timing and engine timing |
| Code type | Generic SAE powertrain code |
| Severity | Moderate to high |
| Safe to drive? | Limited driving may be possible |
| Most common causes | Dirty oil, failed VVT solenoid, low oil pressure, worn timing chain |
| Typical repair cost | $60–$4,000+ |
What Does the P0012 Code Mean?
P0012 means “‘A’ Camshaft Position Timing Over-Retarded Bank 1.”
The ECM monitors the relationship between the crankshaft and camshaft using the:
- Crankshaft position sensor
- Camshaft position sensor
- Variable valve timing solenoid
- Camshaft actuator or phaser
- Engine-oil pressure system
The ECM commands the camshaft to advance or retard based on engine speed, load, temperature and throttle position.
When the actual Bank 1 “A” camshaft position remains more retarded than expected, or fails to move toward the commanded position quickly enough, the ECM stores P0012.
The code may indicate that:
- The camshaft is physically stuck in a retarded position.
- The VVT solenoid is not directing oil correctly.
- Oil pressure is too low to move the camshaft phaser.
- The timing chain has stretched.
- Mechanical timing is incorrect.
- The camshaft position signal does not match the expected value.
P0012 is closely related to:
- P0010: “A” Camshaft Position Actuator Circuit Bank 1
- P0011: “A” Camshaft Position Timing Over-Advanced Bank 1
- P0013: “B” Camshaft Position Actuator Circuit Bank 1
- P0014: “B” Camshaft Position Timing Over-Advanced Bank 1
- P0015: “B” Camshaft Position Timing Over-Retarded Bank 1
- P0016: Crankshaft Position–Camshaft Position Correlation Bank 1 Sensor A
P0012 is primarily a timing-performance code, not simply an electrical circuit code.
What Does “Over-Retarded” Mean?
Camshaft timing is described as advanced or retarded relative to the crankshaft.
When camshaft timing is retarded, the valves open and close later in the combustion cycle.
The ECM may intentionally retard camshaft timing under certain operating conditions. However, P0012 is stored when the camshaft remains farther retarded than commanded.
This can happen when:
- The phaser cannot move.
- Oil pressure is inadequate.
- The solenoid is sticking.
- Oil flow is restricted.
- The timing chain is worn.
- The camshaft timing was installed incorrectly.
An over-retarded intake camshaft can reduce low-speed torque, disrupt idle quality and increase emissions.
What Does Camshaft “A” Mean?
On most dual-overhead-cam engines:
- Camshaft A refers to the intake camshaft.
- Camshaft B refers to the exhaust camshaft.
However, manufacturer terminology can vary.
Always verify the camshaft designation using vehicle-specific repair information before replacing a sensor, solenoid or actuator.
What Is Bank 1?
Bank 1 is the side of the engine containing cylinder number one.
On an inline four-cylinder or inline six-cylinder engine, there is only one cylinder bank, so the entire engine is Bank 1.
On V6, V8, V10 and horizontally opposed engines, Bank 1 may be on either side.
Do not assume Bank 1 is always the driver side or passenger side. Confirm cylinder numbering using:
- Manufacturer service information
- A firing-order diagram
- Engine identification labels
- A repair manual
How Variable Valve Timing Works
Variable valve timing allows the ECM to adjust camshaft timing while the engine is running.
A typical VVT system includes:
- A camshaft phaser
- A VVT solenoid or oil control valve
- Pressurized engine oil
- Camshaft position sensors
- A crankshaft position sensor
- The ECM
- Internal oil passages
The VVT solenoid directs engine oil into chambers inside the camshaft phaser.
Oil pressure moves the phaser, which rotates the camshaft slightly relative to the timing chain or belt.
The ECM uses variable timing to improve:
- Low-speed torque
- High-RPM horsepower
- Fuel economy
- Idle quality
- Cold-start performance
- Exhaust emissions
When the intake camshaft cannot move out of a retarded position, the engine may lose performance and run inefficiently.
Symptoms of the P0012 Code
Some vehicles may show only a Check Engine Light, while others may experience noticeable drivability problems.
Common P0012 symptoms include:
- Illuminated Check Engine Light
- Rough idle
- Poor acceleration
- Reduced engine power
- Engine hesitation
- Hard starting
- Extended cranking
- Engine stalling
- Poor fuel economy
- Increased exhaust emissions
- Engine misfires
- Rattling noise during startup
- Uneven engine operation
- Limp mode
- Failed emissions inspection
- Engine cranks but will not start
The symptoms often become more noticeable when the engine is:
- Cold
- Idling
- Accelerating
- Operating at low RPM
- Running with dirty or low oil
A brief startup rattle may indicate a worn camshaft phaser, weak timing-chain tensioner or delayed oil pressure.
Common Causes of P0012
1. Low Engine Oil Level
Low oil is one of the first conditions to check when diagnosing P0012.
The variable valve timing system relies on engine-oil pressure to move the camshaft actuator.
Low oil can cause:
- Slow phaser response
- Insufficient chain tension
- Inconsistent camshaft movement
- Startup rattling
- Reduced oil pressure
- VVT-related trouble codes
Check the dipstick before replacing any parts.
If the oil level is low, inspect for:
- External oil leaks
- Oil consumption
- Improper previous servicing
- Worn piston rings
- Valve-seal problems
2. Dirty or Contaminated Engine Oil
Dirty oil can restrict the small passages that supply the VVT solenoid and camshaft phaser.
Possible contaminants include:
- Sludge
- Varnish
- Carbon deposits
- Metal particles
- Fuel
- Coolant
- Excessive sealant
Contaminated oil may cause the solenoid or phaser to stick in a retarded position.
An oil and filter change may correct the problem when contamination is minor, but severe sludge may require additional cleaning or mechanical repair.
3. Incorrect Engine-Oil Viscosity
The VVT system is calibrated for a specific oil viscosity.
Oil that is too thick may flow slowly through the actuator passages, especially during cold starts.
Oil that is too thin may fail to maintain adequate pressure in worn components.
Always use the oil grade specified by the manufacturer.
Incorrect oil viscosity is especially likely when P0012 appears immediately after an oil change.
4. Faulty VVT Solenoid
The variable valve timing solenoid controls oil flow to the camshaft phaser.
A failed or sticking solenoid may prevent the intake camshaft from advancing properly.
Possible solenoid problems include:
- Internal electrical failure
- Sticking control valve
- Sludge contamination
- Clogged filter screen
- Metal debris
- Damaged connector
- Excessive resistance
- Open or shorted windings
A solenoid can pass an electrical resistance test and still stick mechanically.
5. Restricted Oil Passages
Small oil passages carry pressurized oil to the VVT solenoid and camshaft phaser.
These passages may become restricted by:
- Sludge
- Carbon
- Metal particles
- Gasket material
- Excessive silicone sealant
- Broken timing-guide debris
Restricted flow can slow actuator movement and cause the camshaft to remain retarded.
6. Low Engine Oil Pressure
The oil level may be correct while actual oil pressure remains too low.
Possible causes include:
- Worn oil pump
- Restricted oil pickup
- Excessive bearing clearance
- Internal oil leaks
- Failed pressure-control valve
- Clogged oil filter
- Damaged oil-pump drive
- Worn camshaft journals
Low pressure can affect both the camshaft phaser and timing-chain tensioner.
A mechanical oil-pressure test may be necessary.
7. Worn or Sticking Camshaft Phaser
The camshaft phaser physically changes camshaft timing.
A worn or sticking phaser may:
- Remain in the retarded position
- Move too slowly
- Fail to hold commanded timing
- Rattle during startup
- Leak oil internally
- Develop excessive mechanical play
A damaged phaser may produce P0012 along with:
- P0011
- P0016
- P0008
- Timing-chain noise
- Camshaft correlation faults
8. Stretched Timing Chain
A worn timing chain can cause the camshaft to operate later than expected relative to the crankshaft.
Timing-chain “stretch” occurs as the chain pins, links and sprockets wear.
Common signs include:
- Startup rattling
- Multiple camshaft timing codes
- Poor acceleration
- Extended cranking
- High camshaft phase error
- Timing marks that no longer align
- Excessive tensioner extension
A stretched chain is more likely on engines with:
- High mileage
- Extended oil-change intervals
- Low oil levels
- Sludge buildup
- Known timing-system problems
9. Failed Timing-Chain Tensioner
The tensioner keeps the timing chain tight.
Many tensioners depend on engine-oil pressure.
A failed tensioner can allow chain slack, causing the intake camshaft timing to remain retarded.
Possible tensioner failures include:
- Weak internal spring
- Hydraulic leakage
- Sludge blockage
- Mechanical collapse
- Loss of pressure after shutdown
- Excessive wear
A tensioner that loses pressure often creates a brief rattle when the engine is started.
10. Worn or Broken Timing Guides
Timing guides keep the chain aligned.
The guides can:
- Crack
- Wear through
- Break apart
- Separate from their mounts
- Allow excessive chain movement
Broken guide material can enter the oil pan and restrict the oil pickup, worsening the oil-pressure problem.
11. Incorrect Mechanical Timing
P0012 may appear after timing-chain, cylinder-head or engine repairs if the engine was assembled incorrectly.
Possible mistakes include:
- Intake camshaft installed one tooth off
- Crankshaft timing mark misaligned
- Chain placed on the wrong marked links
- Phaser installed incorrectly
- Tensioner released incorrectly
- Engine rotated before timing was secured
- Wrong replacement parts
- Incorrect locking-tool use
If P0012 appears immediately after engine work, verify mechanical timing before replacing sensors or solenoids.
12. Damaged VVT Solenoid Wiring
Although P0012 is a performance code, wiring problems can prevent the ECM from controlling the solenoid properly.
Inspect for:
- Broken wires
- Chafed insulation
- Short to ground
- Short to voltage
- Corroded terminals
- Loose connector
- Oil contamination
- Harness damage near the exhaust
Electrical faults may also store P0010.
13. Faulty Camshaft Position Sensor
The camshaft position sensor tells the ECM where the camshaft is located.
A faulty signal may make the ECM believe the camshaft is more retarded than it actually is.
Possible causes include:
- Internal sensor failure
- Metal debris on the sensor
- Damaged wiring
- Connector corrosion
- Incorrect sensor clearance
- Damaged reluctor wheel
A failed camshaft sensor usually causes additional sensor-circuit or correlation codes.
14. Faulty Crankshaft Position Sensor
The crankshaft position sensor provides the reference signal used to calculate camshaft timing.
A distorted crankshaft signal may cause inaccurate camshaft correlation readings.
Possible causes include:
- Sensor failure
- Damaged wiring
- Loose reluctor wheel
- Incorrect sensor air gap
- Connector contamination
- Crankshaft end-play problems
15. Faulty ECM or PCM
An ECM failure is possible but uncommon.
The ECM should only be suspected after verifying:
- Oil level and condition
- Oil pressure
- Mechanical timing
- VVT solenoid operation
- Camshaft phaser movement
- Wiring integrity
- Camshaft and crankshaft signals
Replacement modules may require programming and security-system relearning.
How Serious Is the P0012 Code?
P0012 is generally considered moderately serious, but it can become severe when caused by timing-chain wear or low oil pressure.
Possible consequences include:
- Reduced performance
- Poor fuel economy
- Rough running
- Increased emissions
- Engine stalling
- Catalytic converter damage from misfires
- Timing-chain failure
- Valve-to-piston contact
- Internal engine damage
The code should be treated as urgent if it is accompanied by:
- Loud timing-chain rattle
- Low-oil-pressure warning
- Severe misfires
- Engine stalling
- Multiple correlation codes
- Metal debris in the oil
- No-start condition
Can You Drive With P0012?
A short drive may be possible if:
- The engine runs smoothly.
- Oil pressure is normal.
- No loud timing noise is present.
- The Check Engine Light remains steady.
- The vehicle does not stall.
- Power loss is minor.
Continued driving is not recommended until the cause is diagnosed.
Stop driving immediately if:
- The oil-pressure warning light appears.
- The engine makes loud rattling or knocking noises.
- The engine misfires severely.
- The Check Engine Light flashes.
- The vehicle loses significant power.
- The engine stalls.
- The engine will not restart.
Towing the vehicle may prevent a minor VVT problem from becoming a major engine repair.
How to Diagnose P0012
Step 1: Scan for Additional Codes
Use an OBD-II scanner to check for related trouble codes.
Common companion codes include:
- P0010
- P0011
- P0013
- P0014
- P0016
- P0017
- P0008
- Misfire codes
- Oil-pressure codes
- Camshaft sensor codes
Record:
- Freeze-frame data
- Engine speed
- Engine load
- Oil temperature
- Coolant temperature
- Commanded camshaft angle
- Actual camshaft angle
- Battery voltage
Do not clear the codes before recording this information.
Step 2: Check the Engine Oil Level
Park the vehicle on level ground and follow the manufacturer’s oil-checking procedure.
Check for:
- Low oil level
- Overfilled oil
- Incorrect oil viscosity
- Dirty oil
- Sludge
- Fuel smell
- Coolant contamination
- Metal particles
Correct the oil level before performing advanced testing.
Step 3: Review Maintenance History
Determine:
- When the oil was last changed
- Which viscosity was used
- Whether the oil level has been low
- Whether timing work was recently performed
- Whether the engine has a history of startup rattle
- Whether the vehicle has missed scheduled maintenance
P0012 appearing after an oil change may indicate incorrect oil viscosity, a poor-quality filter or an underfilled engine.
Step 4: Inspect the VVT Solenoid and Wiring
Locate the Bank 1 “A” camshaft actuator solenoid.
Inspect for:
- Broken wires
- Loose connector
- Corrosion
- Oil contamination
- Bent terminals
- Harness rubbing
- Heat damage
- Previous repairs
Repair visible wiring faults before replacing the solenoid.
Step 5: Test the VVT Solenoid Electrically
With the ignition off and connector disconnected:
- Measure solenoid resistance.
- Compare the reading with manufacturer specifications.
- Check the circuit for an open.
- Test for a short to ground.
- Test for a short to voltage.
- Verify power and ECM control.
A solenoid with infinite or extremely low resistance is likely defective.
Step 6: Command the Solenoid With a Scan Tool
A bidirectional scan tool may allow the technician to command the actuator on and off.
Observe:
- Solenoid duty cycle
- Actual camshaft angle
- Engine idle quality
- Current draw
- Response time
- Whether the camshaft moves toward the commanded position
If the electrical command changes but the camshaft does not move, suspect:
- Restricted oil flow
- A sticking solenoid
- A failed phaser
- Low oil pressure
- Mechanical timing problems
Step 7: Remove and Inspect the VVT Solenoid
Remove the solenoid according to manufacturer instructions.
Inspect for:
- Sludge
- Varnish
- Metal debris
- Clogged screens
- Damaged O-rings
- Sticking valve movement
- Broken components
A contaminated solenoid may be cleaned in some applications, but replacement is often more reliable.
Heavy metal contamination may indicate timing-chain, phaser or internal engine wear.
Step 8: Compare Commanded and Actual Camshaft Timing
Monitor scan-tool data while the engine is:
- Idling
- Accelerating
- Decelerating
- Warm
- Cold
A healthy camshaft should closely follow the commanded position.
A camshaft that remains consistently retarded may indicate:
- Chain stretch
- Incorrect mechanical timing
- Low oil pressure
- Sticking phaser
- Restricted oil passage
A camshaft that moves slowly may point toward oil viscosity or flow problems.
Step 9: Check Engine Oil Pressure
Install a mechanical pressure gauge when low pressure is suspected.
Test pressure at:
- Cold idle
- Warm idle
- Increased engine speed
Compare results with factory specifications.
Do not assume oil pressure is adequate because the dashboard warning light is off. The warning switch may activate only when pressure becomes dangerously low.
Step 10: Listen for Timing-System Noise
Start the engine when cold and listen near the timing cover.
Warning sounds include:
- Brief startup rattle
- Continuous chain noise
- Metallic ticking
- Slapping noise
- Rattle that changes with RPM
Startup noise may indicate:
- Weak timing-chain tensioner
- Worn guide
- Stretched chain
- Failing camshaft phaser
Step 11: Inspect Camshaft and Crankshaft Signals
An oscilloscope can display the camshaft and crankshaft waveforms simultaneously.
A trained technician can use waveform correlation to identify:
- Timing-chain stretch
- Incorrect timing
- Shifted reluctor wheel
- Sensor dropout
- Wiring faults
- Unstable camshaft position
This may confirm a timing problem without removing the timing cover.
Step 12: Verify Mechanical Timing
If scan data or waveform analysis indicates a mechanical timing problem, the timing system must be inspected.
This may require removing:
- Valve cover
- Timing cover
- Front engine accessories
- Camshaft access plugs
- Engine mounts
Position the engine at top dead center and compare all timing marks with factory specifications.
Inspect:
- Chain slack
- Tensioner extension
- Guide condition
- Sprocket wear
- Phaser condition
- Camshaft alignment
- Crankshaft alignment
Special locking tools may be required.
Step 13: Check Technical Service Bulletins
Some engines have known issues involving:
- VVT solenoids
- Camshaft phasers
- Timing-chain stretch
- Revised tensioners
- Updated oil recommendations
- ECM calibration
- Oil-filter drain-back problems
- Extended warranty coverage
Review manufacturer service information before performing major repairs.
Step 14: Verify the Repair
After repairs:
- Clear the stored codes.
- Start the engine from cold.
- Listen for abnormal noise.
- Monitor commanded and actual camshaft position.
- Allow the engine to reach operating temperature.
- Complete the required drive cycle.
- Rescan for pending codes.
- Restart the engine several times.
A successful repair should eliminate the code and restore normal camshaft response.
Common P0012 Repairs and Costs
| Repair | Estimated cost |
| Diagnostic inspection | $100–$250 |
| Engine oil and filter change | $60–$180 |
| Repair VVT wiring | $100–$500 |
| Replace VVT connector | $75–$300 |
| Replace VVT solenoid | $150–$500 |
| Clean oil passage or solenoid | $100–$400 |
| Replace camshaft position sensor | $150–$450 |
| Replace camshaft phaser | $600–$1,800 |
| Replace timing-chain tensioner | $500–$1,500 |
| Replace timing chain, guides and tensioners | $1,200–$4,000 |
| Repair cylinder-head damage | $2,500–$6,000+ |
| Replace engine | $4,000–$12,000+ |
| ECM software update | $100–$300 |
| Replace and program ECM | $1,000–$2,500+ |
The final cost depends heavily on engine design.
On some vehicles, the VVT solenoid is externally mounted and easy to replace. On others, camshaft phaser or timing-chain repairs require extensive engine disassembly.
Common Diagnostic Mistakes
Replacing the Camshaft Position Sensor First
P0012 does not automatically mean the camshaft position sensor has failed.
The sensor may be accurately reporting that the camshaft is in the wrong position.
Replacing the VVT Solenoid Without Checking the Oil
Low, dirty or incorrect engine oil is one of the most common contributors to camshaft timing codes.
Always inspect the oil first.
Assuming an Oil Change Will Fix Chain Stretch
Fresh oil may improve a sticking solenoid or hydraulic phaser.
It cannot repair:
- A stretched timing chain
- Worn guides
- A failed tensioner
- A damaged phaser
- Incorrect mechanical timing
Confusing P0012 With P0010
P0010 primarily indicates an actuator electrical-circuit fault.
P0012 indicates the camshaft timing is more retarded than commanded.
The two codes can appear together, but they do not mean the same thing.
Confusing Bank 1 and Bank 2
Bank 1 is the side containing cylinder number one.
Do not assume it is always on a particular side of the vehicle.
Confusing Intake and Exhaust Camshafts
Camshaft A is usually the intake camshaft, but manufacturer terminology should be confirmed.
Skipping Oil-Pressure Testing
Low oil pressure can prevent the phaser from moving even when the solenoid and wiring are functioning correctly.
Ignoring Startup Rattle
Startup rattling may indicate timing-chain, tensioner or phaser wear.
Ignoring it can lead to more serious engine damage.
Replacing the ECM Too Early
ECM failure is much less common than:
- Oil problems
- VVT solenoid failure
- Restricted passages
- Camshaft phaser wear
- Timing-chain problems
Test the entire system before replacing the module.
Vehicles Commonly Affected by P0012
P0012 can appear on nearly any OBD-II vehicle equipped with variable valve timing.
Potentially affected manufacturers include:
- Ford
- Lincoln
- Mazda
- Toyota
- Lexus
- Honda
- Acura
- Nissan
- Infiniti
- Hyundai
- Kia
- Chevrolet
- GMC
- Buick
- Cadillac
- Chrysler
- Dodge
- Jeep
- BMW
- Mini
- Mercedes-Benz
- Volkswagen
- Audi
- Subaru
- Volvo
P0012 is commonly associated with engines that use:
- Oil-controlled camshaft phasers
- Hydraulic VVT solenoids
- Dual-overhead camshafts
- Timing chains
- Small actuator oil passages
- Extended oil-change intervals
Certain engines may have manufacturer-specific diagnostic procedures, updated parts or service bulletins.
The code alone does not prove that a specific model has a known defect.
How to Prevent P0012
Helpful preventive measures include:
- Check the engine oil regularly.
- Use the manufacturer-specified oil viscosity.
- Change the oil and filter on schedule.
- Use a quality oil filter.
- Avoid extended oil-change intervals.
- Repair oil leaks promptly.
- Investigate oil consumption.
- Address startup rattles early.
- Keep VVT solenoids and passages clean.
- Avoid excessive gasket sealant.
- Repair wiring damage promptly.
- Diagnose low-oil-pressure warnings immediately.
- Use complete timing-component kits when required.
- Follow exact mechanical timing procedures.
Clean oil is especially important because the VVT system depends on precise oil flow through small internal passages.
Frequently Asked Questions About P0012
What does code P0012 mean?
P0012 means the Bank 1 “A” camshaft is more retarded than commanded by the ECM or is responding too slowly.
Is Camshaft A the intake camshaft?
On most vehicles, yes.
Camshaft A usually refers to the intake camshaft, but manufacturer terminology should be verified.
Which side is Bank 1?
Bank 1 is the side of the engine containing cylinder number one.
On an inline engine, the entire engine is Bank 1.
What does over-retarded timing mean?
It means the camshaft is opening and closing the valves later than the ECM expects.
Is P0012 an electrical code?
P0012 is primarily a camshaft timing-performance code.
Electrical faults in the VVT solenoid circuit can contribute, but a direct actuator-circuit fault usually stores P0010.
Can dirty oil cause P0012?
Yes. Dirty oil can clog the VVT solenoid or actuator passages and prevent the camshaft from moving properly.
Can low oil cause P0012?
Yes. Low oil can reduce pressure to the camshaft phaser and timing-chain tensioner.
Can the wrong oil viscosity cause P0012?
Yes. Oil that is too thick or too thin may affect VVT response and oil pressure.
Can a bad VVT solenoid cause P0012?
Yes. A sticking or clogged VVT solenoid is one of the most common causes.
Can a stretched timing chain cause P0012?
Yes. A stretched chain can cause the intake camshaft to remain retarded relative to the crankshaft.
Can a bad camshaft sensor cause P0012?
It is possible, but the sensor should be tested before replacement.
The sensor may simply be reporting an actual timing problem.
Can I drive with P0012?
Limited driving may be possible if the engine runs normally and makes no unusual noise.
However, the code should be diagnosed promptly because it may indicate low oil pressure or timing-chain wear.
Can P0012 cause rough idle?
Yes. Incorrect intake camshaft timing can cause unstable idle, hesitation and poor acceleration.
Can P0012 cause a no-start?
Yes. Severe timing problems or a jumped timing chain may prevent the engine from starting.
Will an oil change fix P0012?
It may help if the problem is caused by dirty, low or incorrect oil.
It will not repair a failed solenoid, worn phaser, stretched timing chain or damaged wiring.
How much does it cost to fix P0012?
A basic oil service may cost less than $200.
A VVT solenoid replacement commonly costs $150 to $500, while timing-chain or camshaft phaser repairs may cost $1,000 to $4,000 or more.
Will clearing P0012 fix the vehicle?
No. Clearing the code only turns off the warning temporarily.
The code will return if the camshaft timing remains outside specification.
Will P0012 fail an emissions test?
Yes. An active Check Engine Light or stored emissions-related code will generally cause an OBD-based emissions inspection failure.
Final Thoughts
The P0012 code means the Bank 1 “A” camshaft is more retarded than the ECM expects.
The most common causes include:
- Low engine oil
- Dirty or incorrect oil
- A sticking VVT solenoid
- Restricted oil passages
- Low oil pressure
- A worn camshaft phaser
- A stretched timing chain
- A failed chain tensioner
- Incorrect mechanical timing
- Damaged wiring
Begin diagnosis by checking the engine-oil level, condition and viscosity. Inspect the VVT solenoid and wiring, then compare commanded and actual camshaft position using a capable scan tool.
If the electrical system is working but the camshaft remains retarded, test oil pressure and inspect the camshaft phaser and timing-chain system.
Addressing P0012 early may prevent a relatively inexpensive oil-control problem from becoming a major timing-system or engine repair.
For more diagnostic guides, browse our growing OBD-II libraries:
- Complete OBD-II Code Library: https://my.prostreetonline.com/dtc-obdii/
- Body (B) Codes: https://my.prostreetonline.com/dtc-doctor/b-code-obd-ii-codes/
- Chassis (C) Codes: https://my.prostreetonline.com/dtc-doctor/c-code-obd-ii-codes/
Related Articles
- P0010 Code Explained: “A” Camshaft Position Actuator Circuit Bank 1
- P0011 Code Explained: “A” Camshaft Position Timing Over-Advanced Bank 1
- P0013 Code Explained: “B” Camshaft Position Actuator Circuit Bank 1
- P0014 Code Explained: “B” Camshaft Position Timing Over-Advanced Bank 1
- P0015 Code Explained: “B” Camshaft Position Timing Over-Retarded Bank 1
- P0016 Code Explained: Crankshaft Position–Camshaft Position Correlation Bank 1 Sensor A
