"A" Camshaft Position Timing Over Retarded (Bank 1).


Code P0012 denotes that camshaft timing for engine bank 1 is retarded beyond an acceptable limit. Note: The “A” identifies the intake camshaft, which is located to the intake side of the cylinder head. “Bank 1” denotes the engine bank that contains the number one cylinder.

Code Set Parameters

Variations of 10-degrees (at idle) between the camshaft/s and the crankshaft will result in a code P0012 being stored in the PCM.


Symptoms include roughness when idling and/or accelerating accompanied with reduced fuel economy and engine performance. A code will be stored in the PCM and a malfunction indicator lamp will be illuminated.

Common Causes

Typical causes for this code are a faulty VVT or VCT solenoid, incorrect camshaft timing, or a fault in the connectors or electrical wiring circuitry. Since many VVT and VCT components are stabilized using oil pressure, a low oil level or oil pressure condition could also be a cause of this circumstance. If this code is exhibited immediately after a timing belt or chain replacement, then suspect misalignment of timing components as the primary cause.

Common Misdiagnosis

System sensors and the PCM are often replaced in error, when incorrect timing alignment is the problem.


  • Crankshaft and camshaft positions are monitored using electromagnetic sensors
  • These sensors utilize relief holes in camshaft and crankshaft drive gears to provide signal interruption of the electromagnetic field
  • Interruptions in the electromagnetic field are seen by the PCM as square waveform patterns, which represent varying degrees of voltage
  • These variations in voltage are created using electromagnetic resistance in the 5-volt circuit
  • Some manufacturers use multiple crankshaft sensors to feed separate data streams to the PCM
  • Typically, these data streams provide input for engine ignition and fuel injection timing
  • Engines that are equipped with multiple camshafts generally use a camshaft sensor for each camshaft
  • Other automakers use notches cut into shafts or nodules that are permanently attached to interrupt the electromagnetic field
  • Often these notches or nodules are located near the rear or middle of the shaft, depending upon sensor placement
  • One manufacturer even places the crankshaft sensor on top of the transmission bell-housing and reads crankshaft position from interrupter holes in the flex plate
  • A proper diagnosis should begin with making sure that all engine timing indicators are properly aligned
  • After making sure that timing marks are aligned, test belt or chain deflection using manufacturer’s specifications
  • VVT or VCT solenoids and circuitry should be tested if timing components prove to be properly aligned and in good working order
  • PCM and sensor failure are rare
  • Electrical wiring and connectors are more prone to fail than sensors, especially where oil or other corrosive fluids are present. Several tools will be instrumental in successfully diagnosing this code
  • A suitable OBD-II scanner (or code reader), a digital volt/ohmmeter, and an oscilloscope will be most helpful in performing a successful diagnosis
  • A manufacturer’s service manual (or the equivalent) will also be necessary
  • Begin with a visual inspection of all wiring and connectors
  • Repair or replace damaged, disconnected, shorted, or corroded wiring, connectors, and components as necessary
  • Always retest the system after repairs are completed to ensure success. If all system wiring, connectors, and components (Including fuses) appear to be in normal working order, connect the scanner (or code reader) to the diagnostic connector and record all stored codes and freeze frame data
  • This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
  • Continue by clearing the code and operating the vehicle to see if it returns
  • This will help to determine whether or not the malfunction is intermittent
  • After the codes are cleared, test drive the vehicle to see if the code returns
  • If the code fails to immediately return, you may have an intermittent condition
  • Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made. After disconnecting the connector from the affected sensor, check for a reference voltage signal (usually 5-volts.) and a ground at the connector end (key on/engine off)
  • If reference voltage and/or ground are not detected, disconnect the connector from the PCM and test all circuits for resistance and continuity
  • Consult the manufacturer’s service manual for wiring diagrams, technical service bulletins, and/or flow charts that may be helpful
  • Repair or replace circuits, connectors, or components that do not comply with manufacturer’s specifications, as required
  • After repairs are made, clear codes and test drive the vehicle to ensure that your repair has been successful. If reference voltage and ground signals are present, reconnect the sensor and use the oscilloscope to monitor live data wave form patterns
  • Look for abnormalities in the wave form and replace the sensor in question if present
  • After repairs are made, clear codes and test drive the vehicle to ensure that your repair has been successful. If wave for patterns appear to be normal, suspect a defective PCM
  • Remember, PCM failure is rare and replacement will require reprogramming
  • Some applications require camshaft and crankshaft sensor replacement in sets
  • Consult your service manual for specific instructions