What causes fault code P0393?

• Most likely: Faulty Camshaft Position Sensor (internal short circuit) • Likely: Damaged wiring harness or short to voltage in the signal wire • Possible: Oil or moisture contamination in the connector causing bridging • Rare: Reluctor wheel damage or excessive camshaft end play

Powertrain (Engine & Gearbox)Standard EOBD

P0393 - Camshaft Position Sensor B Circuit High Intermittent (Bank 2)

Q: What are the symptoms of fault code P0393?

• Check Engine Light (MIL) illumination • Hard starting or long cranking times • Engine stalling or hesitating during acceleration • Reduced engine performance and poor fuel economy • Vehicle may enter 'Limp mode'

Q: How do you fix fault code P0393?

STEP 1: Inspect the connector at sensor B, bank 2 for corrosion, oil intrusion, or bent pins. Clean as necessary. STEP 2: Inspect wiring between the sensor and ECU. Use a multimeter to verify stable reference voltage (5V/12V) and ground. Ensure the signal wire is not shorted to power. STEP 3: Use an oscilloscope to monitor the sensor signal waveform while the engine is running. Look for a clean square wave (Hall) or sine wave (VR). Monitor for voltage spikes while wiggling the harness. STEP 4: If wiring is intact but the signal is erratic or stuck high, replace the camshaft position sensor. Clear codes and perform a test drive.

Last updated:1 February 2026

Related:Camshaft Position Sensor (CMP), Crankshaft Position Sensor (CKP), Engine Control Unit (ECU), Wiring Harness, Kamrem/Kamkedja

System

Powertrain (Engine & Gearbox)

Related Fault Codes

P0300

Random or Multiple Cylinder Misfire Detected

P0301

Cylinder 1 Misfire Detected

P0302

Cylinder 2 Misfire Detected

P0303

Cylinder 3 Misfire Detected

Technical Description

The P0393 code is set when the Engine Control Unit (ECU) detects an intermittent high voltage signal from the Camshaft Position Sensor 'B' on Bank 2. Bank 2 refers to the side of the engine that does not contain cylinder 1, and sensor 'B' typically indicates the exhaust camshaft sensor. The sensor is a Hall-effect or variable reluctance type used to monitor camshaft speed and position. When the circuit voltage exceeds a calibrated threshold (often close to the 5V or 12V reference) intermittently, the ECU loses the ability to synchronize fuel injection and spark timing effectively.

Possible Causes

Faulty Camshaft Position Sensor (internal short circuit)

Damaged wiring harness or short to voltage in the signal wire

Oil or moisture contamination in the connector causing bridging

Reluctor wheel damage or excessive camshaft end play

Symptoms

Check Engine Light (MIL) illumination

Hard starting or long cranking times

Engine stalling or hesitating during acceleration

Reduced engine performance and poor fuel economy

Vehicle may enter 'Limp mode'

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P0393 - Camshaft Position Sensor B Circuit High Intermittent (Bank 2)

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P0393 - Camshaft Position Sensor B Circuit High Intermittent (Bank 2)

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