Camshaft Position Sensor A Circuit Range/Performance (Bank 1 or Single Sensor)
What it means
The signal from camshaft position sensor A is present, but the engine computer finds it implausible: the pulse count or timing does not match the crankshaft sensor signal. The cause may be a weak sensor or electrical noise, but it can also indicate an engine timing problem that deserves a serious check.
Symptoms5
- Check engine light on.
- Long cranking or rough running right after starting.
- Reduced power and hesitation on acceleration.
- Rattle from the timing chain area on cold starts in some cases.
- Intermittent stalling.
Possible causes6
- Weak sensor producing a noisy or incomplete signal.
- Stretched timing chain or a timing belt that has jumped one or more teeth.
- Damaged or bent tooth wheel read by the sensor.
- Electrical noise from ignition wiring or the alternator on the sensor wires.
- Incorrect sensor or a sensor not seated properly.
- Low cranking voltage from a weak battery or starter.
How to diagnose5
- Read stored codes; P0016 or cam timing codes such as P0011 alongside it point to a mechanical timing problem.
- View the cam and crank sensor signals together on an oscilloscope and compare the pattern with the known-good pattern for the engine.
- Check that the sensor wiring is routed away from ignition wires and that the ground is sound.
- Inspect the sensor tip for metal debris or damage and confirm it is seated firmly.
- If timing looks off, check the timing marks and chain or belt condition per the manufacturer procedure.
How to fix5
- Repair or reroute the wiring away from noise sources and clean the connector.
- Clean debris from the sensor tip or replace the sensor with a matching part.
- Fix a weak battery or low cranking voltage.
- Replace the timing chain or belt, along with the tensioner and gears, if stretch or a jumped tooth is confirmed.
- Clear the codes, road test and confirm the code does not return and the two signals match.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
The cost is low when a sensor or wiring is to blame, and reaches the upper end when the engine needs a timing chain or cam gear replacement.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
Does this code mean the timing chain is stretched?
Not always. A weak sensor or wiring noise can cause it, but if P0016 is also stored or there is a rattle on startup, check the timing before anything else.
Why did the code come back after a new sensor?
Because the sensor reads what is really happening. If the timing is off or the tooth wheel is damaged, even a new sensor will keep sending an implausible signal.
This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.
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