P0335: Crankshaft Position Sensor "A" Circuit

What does P0335 mean?

The crankshaft position (CKP) sensor reports the speed and position of the crankshaft. The ECM uses it to time the spark and fuel injection, so a missing signal can stop the engine from running.

P0335 sets when the signal is missing, intermittent or does not make sense. Some engines keep running on backup logic, while others stall or will not start.

Common symptoms

• Check engine light on
• Hard starting or cranking without starting
• Stalling or the engine dying while driving
• Rough running or hesitation
• Sometimes no other symptom if the fault is intermittent

Common causes

The causes below are the ones commonly seen with P0335. The actual cause can vary by vehicle, engine and mileage, so treat this list as a starting point, not a diagnosis.

• A faulty crankshaft position sensor
• Damaged, chafed or corroded sensor wiring or connector

What to check with a scanner

• If the engine cranks but will not start, watch the rpm reading in Live data while cranking. No rpm signal is consistent with a crankshaft sensor circuit problem.
• Check freeze frame data to see whether the code set at a particular temperature or speed, which can point to an intermittent wiring fault.
• Inspect the sensor connector and wiring for damage or oil contamination.
• Note any camshaft position codes, such as P0340, stored at the same time.

How to read and clear P0335 with OBD Master Pro

1. Plug in your adapter. Connect a generic ELM327 (or ELM329) OBD2 adapter to the diagnostic port, usually under the dashboard on the driver's side. Bluetooth Classic, Bluetooth LE, Wi-Fi and USB OTG adapters are supported.
2. Switch the ignition on. Turn the key to ON or start the engine, depending on your car.
3. Connect in OBD Master Pro. Open the app, go to Connection and pick your adapter. Classic Bluetooth adapters connect from the Bluetooth tab, Bluetooth LE adapters from the BLE tab with no pairing needed. Use the generic OBD2 / EOBD profile or your car's brand profile.
4. Read the codes. Open the fault codes screen to see stored, pending and permanent codes. Confirm P0335 is listed and note any other codes, since they often explain the cause.
5. Check the details. Look at freeze frame data, Live data and, where your car supports it, Mode 06 test results (see the checks above).
6. Fix, then clear. After the repair, clear the codes to turn off the check engine light. Clearing also resets the emissions readiness monitors, so drive normally and check the readiness screen before any inspection. Permanent codes cannot be erased with a scan tool; they clear on their own once the car's self test passes.

Tip: you can also look up P0335 and other codes in the app's DTC search without connecting to a car. If your adapter will not connect, use Connection > Share connection log and email it to support. Many cheap ELM327 clones only handle basic engine OBD2, which is all you need for P0335.

When to see a mechanic

Get professional help if any of these apply:

• The engine will not start or stalls while driving
• The code returns after replacing the sensor
• You need scope or resistance tests on the sensor circuit

If you are unsure, a qualified technician can confirm the cause with tests such as smoke testing, pressure testing or scope readings. Clearing a code does not repair the fault.

Related trouble codes

See all OBD2 trouble code guides

Related guides

Check engine light on: what to do · How to read an OBD2 code (P, B, C, U) · Stored, pending and permanent codes and freeze frame · OBD2 readiness monitors explained · OBD2 glossary · OBD2 by car brand