How is fault code P0338 fixed?

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Read the freeze-frame data with a scanner and note whether the fault landed during cranking, hot running, or cold starts. That tells you a lot about where to look 2. Unplug the sensor and check the connector for oil, corrosion, and pushed-back pins. A connector full of oil is a frequent culprit and a cheap fix 3. Back-probe the signal and supply wires with the ignition on, you're looking for the expected reference of around 5 volts, not a stuck-high reading 4. Watch the live sensor signal while cranking to see if the voltage exceeds the upper limit or drops out altogether 5. Measure the sensor resistance with a multimeter and compare against the manufacturer's figure for that engine 6. Inspect the reluctor ring through the sensor hole for chipped or damaged teeth before condemning anything electrical

Crankshaft Position Sensor A Circuit High Input

Jump to the fix

Severity

High

Can I keep driving?

Avoid extended driving; visit a service soon.

First step

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Read the freeze-frame data with a scanner and note whether the fault landed during cranking, hot running, or cold starts. That tells you a lot about where to look 2. Unplug the sensor and check the connector for oil, corrosion, and pushed-back pins.

PPowertrain
0Generic code
3Ignition / Misfire
38Sequence number

What does it mean?

Three things are needed for the engine to run: air, fuel, and spark. To run well, the ECM (engine control module) precisely meters how much fuel to inject for the measured mass of air at any given moment, and then deliver a spark to ignite a power stroke, hundreds of times per second. Of course, this all requires precise timing, for which the ECM uses the camshaft and crankshaft position sensors (CMP and CKP). The crankshaft position signal serves two important functions.

First, it functions as a speed sensor, which the ECM uses to calculate engine speed in revolutions per minute (rpm). Second, CKP functions as a position sensor, which the ECU uses to calculate the position of cylinder #1 at top-dead-center (TDC). The ECU uses rpm and TDC measurements to calculate injector pulse width (IPW), ignition timing, and variable valve timing (VVT), among other things, and can even detect cylinder misfires.

If ECU detects too much voltage coming from the CKP sensor, it sets DTC P0338 Crankshaft Position Sensor “A” Circuit High Input.

Symptoms

Likely causes

How to fix it

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This information follows the generic OBD-II definition and does not replace a vehicle-specific diagnosis. The severity rating is rule-based; an authorised diagnostic reading is required for a definitive answer.