What causes fault code P0338?

• Most likely: Faulty Crankshaft Position (CKP) sensor (internal short) • Likely: Short to voltage in the sensor signal wiring harness • Possible: Poor ground connection for the sensor circuit • Rare: Reluctor ring (tone wheel) damage or misalignment • Rare: Internal PCM/ECU failure

Powertrain (Engine & Gearbox)Standard EOBD

P0338 - Crankshaft Position Sensor 'A' Circuit High Input

Q: What are the symptoms of fault code P0338?

• Check Engine Light (MIL) illuminated • Engine may not start (no-start condition) • Engine stalling or hesitating • Tachometer does not move while cranking • Vehicle may enter Limp Home Mode

Q: How do you fix fault code P0338?

STEP 1: Visually inspect the CKP sensor connector and wiring for signs of corrosion, damage, or oil contamination. STEP 2: Use a multimeter to check the reference voltage (typically 5V or 12V) and ground at the sensor plug. Verify that the signal wire is not shorted to the power wire. STEP 3: Perform an oscilloscope test while cranking. A healthy sensor produces a pulse pattern. If the signal remains high at all times, the sensor or harness is faulty. STEP 4: Replace the CKP sensor if testing confirms an internal fault. Clear codes and perform a Crankshaft Variation Learn procedure if required by the vehicle manufacturer.

Last updated:1 February 2026

Related:Crankshaft Position Sensor, Triggerhjul (Reluctor Ring), Engine Control Unit (ECU/PCM), Kablage och kontaktstycken

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

P0338 is an OBD-II diagnostic trouble code (DTC) indicating that the Powertrain Control Module (PCM) has detected a voltage signal from the Crankshaft Position (CKP) sensor 'A' that is higher than the expected range. The CKP sensor monitors engine RPM and crankshaft position for ignition timing and fuel injection synchronization. A 'High' condition typically means the signal wire is shorted to a power source or there is a loss of ground, preventing the PCM from seeing the normal pulse pattern required for engine operation.

Possible Causes

Faulty Crankshaft Position (CKP) sensor (internal short)

Short to voltage in the sensor signal wiring harness

Poor ground connection for the sensor circuit

Reluctor ring (tone wheel) damage or misalignment

Internal PCM/ECU failure

Symptoms

Check Engine Light (MIL) illuminated

Engine may not start (no-start condition)

Engine stalling or hesitating

Tachometer does not move while cranking

Vehicle may enter Limp Home Mode

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P0338 - Crankshaft Position Sensor 'A' Circuit High Input

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P0338 - Crankshaft Position Sensor 'A' Circuit High Input

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