P0339

Crankshaft Position Sensor A Circuit High Input

Powertrain Ignition System Crankshaft Position Sensor Circuit 🟡 Moderate — Fix within a week ⚠️ Drive with Care
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What This Actually Means

In plain language — no jargon

The crankshaft position sensor is sending a voltage signal that's too high to the engine computer, like a radio stuck on maximum volume. The ECU can't properly read engine timing, which disrupts ignition and fuel injection.

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Symptoms You May Notice

3 known symptoms for this code
Engine won't start or starts intermittently
Check Engine Light illuminated
Rough idle and stalling at stops
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECM monitors the analog voltage output from the crankshaft position sensor (CKP), which typically fluctuates between 0.5V and 4.5V as the crankshaft rotates. When voltage remains consistently above the upper threshold (usually >4.8V), the ECM detects a circuit high condition and triggers P0339.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
CKP Sensor Voltage 0.5V to 4.5V (varying with RPM) Above 4.8V continuously
Signal Pattern Regular pulse frequency matching crankshaft rotation No valid signal or stuck high signal
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Wiring harness and connectors
Inspect CKP sensor connector for corrosion, loose pins, or damaged wires; clean or reseat connections.
2
Crankshaft Position Sensor
Unplug the sensor from its location near the crankshaft pulley, visually inspect for damage, and test with a multimeter or replace if faulty.
3
Engine Control Module (ECM) wiring
Check ECM connector pins for corrosion or bent terminals; clean and reseat if needed, or replace ECM if internal failure is suspected.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code P0339 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.
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How to Clear Code P0339

What happens after you fix the fault

Once the fault is repaired, P0339 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When
  • Fault has been diagnosed and repaired
  • You want to confirm the repair worked
  • Code appeared after a sensor was cleaned
⚠️ Do Not Clear When
  • Preparing for an emissions/PUC test
  • Root cause is still undiagnosed
  • Check engine light is flashing
Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.