How do you fix fault code P0370?

STEP 1: Visually inspect wiring and connectors to the crankshaft and camshaft sensors for corrosion or loose pins. STEP 2: Verify reference voltage (typically 5V or 12V) and ground at the sensor using a multimeter. Ensure signal wire resistance is near 0 Ohms. STEP 3: Use an oscilloscope to analyze the waveform of signal 'A'. The signal should exhibit clean square waves without noise or dropouts. STEP 4: Clean the sensor tip and inspect the reluctor ring for physical damage. If the signal remains erratic despite verified wiring, replace the sensor.

Powertrain (Engine & Gearbox)Standard EOBD

P0370 - Timing Reference High Resolution Signal A Malfunction

Q: What are the symptoms of fault code P0370?

• Check Engine Light (MIL) illuminated • Engine hard to start (extended cranking) • Engine misfiring at high RPM • Engine stalling or entering Limp Home Mode • Reduced engine power and erratic idling

Q: What causes fault code P0370?

• Most likely: Faulty optical or electromagnetic sensor (crankshaft/camshaft) • Likely: Wiring issues (poor connections or chafed wires) causing EMI/RFI interference • Possible: Contamination or debris on the reluctor ring/tone wheel • Rare: Internal Engine Control Module (ECM) failure

Last updated:1 February 2026

Related:Crankshaft Position Sensor (CKP), Camshaft Position Sensor (CMP), Engine Control Module (ECM), Reluctor Ring, Wiring Harness

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

P0370 is set when the Engine Control Module (ECM) detects an instability or failure in the high-resolution timing reference signal 'A'. The ECM uses this high-frequency pulse signal to precisely determine ignition timing and fuel injection duration. If the number of pulses per revolution deviates from the expected value or if the signal is noisy, the ECM cannot accurately synchronize the engine cycles, leading to performance issues and potential limp mode.

Possible Causes

Faulty optical or electromagnetic sensor (crankshaft/camshaft)

Wiring issues (poor connections or chafed wires) causing EMI/RFI interference

Contamination or debris on the reluctor ring/tone wheel

Internal Engine Control Module (ECM) failure

Symptoms

Check Engine Light (MIL) illuminated

Engine hard to start (extended cranking)

Engine misfiring at high RPM

Engine stalling or entering Limp Home Mode

Reduced engine power and erratic idling

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P0370 - Timing Reference High Resolution Signal A Malfunction

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P0370 - Timing Reference High Resolution Signal A Malfunction

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