Signal wire shorted to earth or chafed against the body or engine; Faulty actuator position sensor, or an actuator with an integrated sensor that has failed; Damaged, corroded or loose connector terminals at the sensor or control unit; Open circuit or high resistance in the sensor reference supply wire; Oil contamination or oil ingress into the connector or sensor; Faulty engine control unit; Mechanical fault in the actuator or camshaft phasing mechanism causing an implausible signal.

P03E7

A Camshaft Position Actuator Position Sensor C Circuit Low Bank 1.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
3: AreaIgnition system or misfire
E7: FaultThe specific fault in that area

What it means

P03E7 means the engine control unit has seen a voltage that is too low on the circuit for camshaft position actuator position sensor 'C' on Bank 1. This sensor reports the position of a camshaft phasing or lift actuator back to the control unit. Which actuator counts as sensor 'C' (intake or exhaust, or a particular actuator) depends on the engine and model. The code sets when the signal voltage stays below the expected range, which points to a short to earth, an open supply or a faulty sensor.

Symptoms

Engine warning light on
Reduced power or hesitation, as the control unit may limit variable valve timing or lift
Rough idle or occasional stalling
Poor fuel economy
Hard starting in some cases

Possible causes

Signal wire shorted to earth or chafed against the body or enginelikely
Faulty actuator position sensor, or an actuator with an integrated sensor that has failedlikely
Damaged, corroded or loose connector terminals at the sensor or control unitlikely
Open circuit or high resistance in the sensor reference supply wirepossible
Oil contamination or oil ingress into the connector or sensorpossible
Faulty engine control unitrare
Mechanical fault in the actuator or camshaft phasing mechanism causing an implausible signalrare

How to diagnose

Read all stored codes and freeze frame data, noting engine temperature, speed and load when the fault set, and check for other cam or actuator codes.
Check for oil level or condition problems, as these can affect actuator operation, and look for oil in the sensor connector.
Visually inspect the Bank 1 sensor wiring and connector for chafing, heat damage, corrosion, pushed-out pins or oil contamination.
Using the manufacturer's wiring diagram to identify which sensor is 'C' on this engine, check the sensor reference supply and earth with a multimeter.
Check the signal wire for a short to earth and for continuity back to the control unit with the connectors disconnected.
Wiggle test the harness with the engine running and watch live sensor data for dropouts or a signal stuck low.
Compare the live actuator position data with the commanded position, using the manufacturer's procedure for that engine.
Inspect the actuator and sensor for mechanical damage or play, only after the wiring has been proven good.

How to fix

Repair or replace the damaged section of wiring, especially any short to earth or open circuit.
Clean or replace the corroded or damaged connector and terminals.
Replace the faulty position sensor or actuator assembly, depending on how the sensor is fitted on that engine.
Fix any oil leak or contamination feeding into the connector, and replace the affected harness section if oil has wicked into it.
If all wiring and the sensor test good and the control unit is suspected, have it checked and, if needed, replaced or reprogrammed to the manufacturer's procedure.

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but power may be limited and the fault can worsen or affect timing control. Get it diagnosed soon, and stop driving if it runs very roughly or stalls.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.