P0338
Crankshaft Position Sensor A Circuit High Input
If your vehicle's onboard computer has flagged the diagnostic trouble code P0338, it refers to a detected anomaly regarding "Crankshaft Position Sensor A Circuit High Input". This systemic engine fault needs a targeted check before symptoms expand.
Driver's Summary
Your vehicle's computer logged P0338 after detecting a malfunction in the crankshaft position sensor a circuit high input system. On the road, this usually shows up as no start condition, engine misfires severely, mil illuminated. Stop driving as soon as it is safe to do so. This fault can lead to expensive secondary damage if left unaddressed.
Symptoms
No start condition, engine misfires severely, MIL illuminated
Common Causes
- Short to battery voltage in circuit
- Open ground connection for sensor
- Defective crankshaft position sensor
- Broken reluctor ring
How to Fix
- 1 Repair short to voltage
- 2 Fix broken ground wire
- 3 Replace crankshaft position sensor
- 4 Inspect and replace reluctor ring
Technical Explanation
The PCM triggers P0338 after its internal monitoring routine detects that a specific circuit or sensor has exceeded its acceptable operating range. The PCM monitors crankshaft rotational velocity via the CKP sensor at a resolution of individual tooth gaps on the reluctor ring. A combustion event in each cylinder produces a measurable acceleration spike; its absence or weakness is flagged as a misfire event within a 200-revolution or 1000-revolution test window. Once confirmed, the code is stored as a permanent DTC and the MIL is activated. The freeze frame snapshot — recording RPM, load, coolant temperature, and fuel trim at fault detection — is also saved and is critical for accurate diagnosis.
Is It Safe to Drive?
This fault carries real mechanical risk. The root causes — including short to battery voltage in circuit — can trigger a chain reaction of component failures if the vehicle continues to be driven. Have it towed or drive directly to a shop without delay.
Mechanic's Pro Tip
The most common mistake with P0338 is replacing the sensor without verifying the reference voltage and ground integrity first. Use a scan tool to monitor the sensor's live output; a truly failed sensor shows a stuck, flatlined reading — a sensor that fluctuates but reads slightly off usually indicates a wiring or vacuum issue, not a dead sensor. Always spray electrical contact cleaner on the connector pins before condemning the sensor.
Related Fault Codes
Frequently Asked Questions
What does OBD2 code P0338 mean?
OBD2 code P0338 refers to Crankshaft Position Sensor A Circuit High Input. If your vehicle's onboard computer has flagged the diagnostic trouble code P0338, it refers to a detected anomaly regarding "Crankshaft Position Sensor A Circuit High Input". This systemic engine fault needs a targeted check before symptoms expand.
What are the most common symptoms of DTC P0338?
Drivers experiencing code P0338 typically report: No start condition, engine misfires severely, MIL illuminated.
Is it safe to drive with trouble code P0338 active?
This fault carries real mechanical risk. The root causes — including short to battery voltage in circuit — can trigger a chain reaction of component failures if the vehicle continues to be driven. Have it towed or drive directly to a shop without delay.
How much does it cost to fix code P0338?
The estimated repair cost for P0338 ranges from $100 to $600 USD. Sensor: 150 - 350; Reluctor ring: 400 - 600
Sensor: 150 - 350; Reluctor ring: 400 - 600
Need Professional Diagnostic Assistance?
Always verify sensor signals and wiring integrity with an OBD2 scanner before purchasing replacement parts.
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