EN

Severity: Moderate Code type: Generic (all makes)

P0012 Code: "A" Camshaft Position Timing Over-Retarded (Bank 1)

The bank 1 intake cam lags behind the angle the PCM wants, often from chain stretch or weak oil supply.

At a glance

Severity: 3/5 – Moderate3/5

Severity: Moderate

Meaning
"A" Camshaft Position Timing Over-Retarded (Bank 1)
System
Fuel & Air Metering · Powertrain
Safe to drive?
With caution
Typical repair cost
$120–$2,400
DIY difficulty
Moderate

When you accelerate or cruise, the PCM rotates the bank 1 intake camshaft ahead of its base position to fill the cylinders better and trap some exhaust for internal EGR. P0012 means the measured angle is later, or more retarded, than commanded by more than the allowed margin for a set time. Where P0011 is usually about a phaser that won't return home, this code is about a cam that can't reach its target or reads late all the time. Typical reasons are a phaser that loses oil pressure once the oil is hot and thin, a lock pin that stays engaged, or a timing chain that has stretched so the whole camshaft trails the crankshaft. A chain or belt job done one tooth off gives exactly the same result.

Can I keep driving? The engine usually idles fine but feels flat below the mid-range. Short trips are acceptable; if you hear the timing chain rattle or clatter, stop and have it towed, because a stretched chain can jump a tooth.

How to read P0012

How to read P0012P10203124
  1. P Powertrain
  2. 0 Generic (SAE)
  3. 0 Fuel/air & emissions (aux.)
  4. 12 Specific fault

Symptoms

  • Noticeably weaker pull from low rpm, as if the engine were down on power
  • Idle often sounds normal and the problem only shows while driving
  • Worse highway fuel economy
  • Code sets after a long drive or in hot weather when the oil is thin
  • One- or two-second rattle on a cold start from the lock pin or chain tensioner
  • Check engine light, sometimes with P0016 stored alongside

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Timing chain stretched or guides worn, so the intake cam always reads late 24%
  2. Phaser lock pin stuck engaged, or phaser vanes worn and leaking 20%
  3. Oil pressure too low at hot idle: low level, worn oil pump or worn bearings 18%
  4. Oil control valve stuck in the retard or drain position, or its screen blocked 16%
  5. Cam timing set one tooth late during an earlier chain or belt job 12%
  6. Oil thinned by fuel dilution from constant short trips or a leaking injector 10%

Diagnosis step by step

Diagnostic flow: P00121Read the freeze frame first2Check cam angle with the phaserparked3Command advance above idle4Measure oil pressure with amechanical gauge5Inspect the control valve and itsO-rings6Verify the timing marks after anyengine work

  1. Read the freeze frame first

    Note engine rpm, load and oil or coolant temperature when the code set. A code that only appears hot and at low rpm leans toward oil pressure; one that sets anywhere, even right after a cold start, leans toward a fixed mechanical offset.

    Tools: OBD-II scanner

  2. Check cam angle with the phaser parked

    At warm idle, with the phaser commanded to its base position, the actual intake angle should read at or very close to zero. A steady offset of several degrees late while parked means the phaser isn't the issue at all; the chain or the cam timing itself is off. Compare with the crank/cam correlation value if your scan tool shows one.

    Tools: OBD-II scanner

  3. Command advance above idle

    Hold about 1,500 to 2,000 rpm in Park and command 20 to 30 degrees of intake advance. Actual should follow within roughly a second. If it creeps up slowly or stalls halfway, the phaser isn't getting enough oil or is leaking internally.

    Tools: OBD-II scanner

  4. Measure oil pressure with a mechanical gauge

    Fit a mechanical gauge in place of the oil pressure switch and compare hot-idle and 2,000 rpm readings with the factory spec. Low hot-idle pressure starves the phaser first and also explains a tensioner that rattles. Reinstall the switch to its torque spec with fresh sealant.

    Tools: Torque wrench, Flashlight

  5. Inspect the control valve and its O-rings

    Pull the valve and check for cut O-rings that bleed pressure, a blocked screen, or a spool stuck toward the drain side. A valve that won't open the advance port keeps the cam fully retarded no matter what the PCM commands.

    Tools: Screwdriver, Multimeter

  6. Verify the timing marks after any engine work

    If the engine has had chain, belt or head work, remove the valve cover and check the marks or fit the locking tools at top dead center. One tooth late shows up as the same fixed retard on every scan, and no amount of solenoid work will cure it.

    Tools: Flashlight, Torque wrench

Where the parts are

Ignition: coils and spark plugs per cylinder – P00121234567
Ignition: coils and spark plugs per cylinder
  1. 1Ignition coil
  2. 2Spark plug
  3. 3Fuel injector
  4. 4Camshaft sensor
  5. 5Crankshaft sensor
  6. 6Engine computer (ECM)
  7. 7Intake manifold

Repair options & costs

RepairDIY?Estimated cost
Replace intake oil control valve and O-rings Yes $120–$350
Re-time the engine after an incorrect chain or belt job No $300–$900
Replace intake cam phaser No $600–$1,500
Oil pump replacement No $500–$1,400
Timing chain kit with guides and tensioner No $1,000–$2,400

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Notes by brand

Honda

Honda's K24 four-cylinder in the Accord, CR-V and Element is known for a VTC actuator, its intake cam phaser, whose lock pin wears and makes a loud grinding rattle for a second or two on cold starts. A worn actuator can also log intake cam timing codes; the usual fix is a new actuator, often together with the chain and tensioner.

Field data

Ford 23 Escape, F-150 SUPERCAB, Ecosport
Toyota 5 Avalon, RAV4, Sienna

Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.

Emissions / smog test impact

Will fail

OBD-II emissions stations fail any car whose check engine light is commanded on, so P0012 has to be repaired before the test. Afterward, allow a few days of normal driving so the monitors are ready; clearing codes just before the visit gets you turned away as not ready.

Frequently asked questions

Can a timing belt or chain job cause P0012?

Yes, it's one of the most common causes right after a repair. If a cam sprocket went on one tooth late, the cam reads retarded all the time. The cure is re-timing the engine, not new parts.

Will thicker oil fix P0012?

It may hide the fault for a while by raising hot oil pressure, but the phaser is built for the specified grade and your next code may be P0011. Find out why pressure is low instead: fuel-diluted oil, a tired pump or worn bearings.

Why does the code only show up on long highway drives?

Oil gets hotter and thinner the longer you drive. A marginal pump or a leaky phaser keeps up while the oil is cool and falls behind once it's hot, so the cam never quite reaches its target.

Is it safe to keep driving with P0012?

For a short time, if the engine is quiet. When the cause is a stretched chain, it can eventually skip a tooth, and on interference engines that bends valves. Any new rattle means park the car.

Sources