P0393

What it means

P0393 is the generic code for a high signal in the Camshaft Position Sensor B circuit on Bank 2. The engine control unit has seen the sensor signal or circuit voltage sit above the expected range, or the signal pattern is not plausible, so it has set the fault. Sensor B is usually the exhaust camshaft sensor, but the exact naming and location depend on the engine.

Symptoms

• Engine management light on
• Hard starting or extended cranking
• Rough idle or misfire
• Loss of power or poor acceleration
• Engine stalling
• Poor fuel economy

Possible causes

• Faulty camshaft position sensor B on Bank 2likely
• Damaged, chafed or corroded wiring in the sensor signal, reference or ground circuit, including a short to voltagelikely
• Loose, corroded or contaminated connector at the sensor or control unitlikely
• Damaged or loose reluctor or trigger wheel, or an air gap problem at the sensorpossible
• Camshaft timing out of position due to a stretched chain, worn tensioner or jumped beltpossible
• Oil contamination or metallic debris on the sensor tippossible
• Faulty engine control unitrare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, such as engine speed, load and temperature, to see when the fault set.
2. Check for related codes, such as other camshaft or crankshaft sensor faults, misfire or timing correlation codes, as these help separate a sensor fault from a timing problem.
3. Visually inspect the Bank 2 sensor B, its connector and the wiring for damage, chafing, oil ingress, heat damage and corrosion.
4. Check the sensor tip for debris or damage and check it is seated correctly and secured, referring to the model-specific procedure for its location.
5. Wiggle test the harness and connector with the engine running while watching live data for signal dropouts or spikes.
6. Check the sensor supply, signal and ground circuits for a short to voltage, open circuit or high resistance, following the wiring diagram for the engine.
7. Compare live camshaft and crankshaft signal data, or view the waveform on an oscilloscope, to check the signal pattern and timing correlation.
8. If the sensor and wiring are sound, check mechanical cam timing and the condition of the trigger wheel against the manufacturer's specification.

How to fix

• Replace the Bank 2 camshaft position sensor B if it has failed testing.
• Repair or replace damaged wiring and fix any short to voltage in the circuit.
• Clean, repair or replace corroded or loose connectors and terminals.
• Refit or replace a loose or damaged trigger wheel, and correct the sensor air gap where applicable.
• Correct camshaft timing by replacing worn chain, tensioner, guides or belt components as the engine requires.
• Only if all else is sound, diagnose the control unit fault and repair or replace it as advised by the manufacturer.

Can I keep driving?

Nearby codes

• P0392GenericCamshaft Position Sensor B Circuit Low Bank 2
• P0394GenericCamshaft Position Sensor B Circuit Intermittent Bank 2