Failed crankshaft position sensor (CKP) due to heat, contamination, or internal winding failure; Damaged or chafed wiring between the CKP sensor and the ECM, often near exhaust manifolds or sharp brackets; Corroded or loose CKP sensor connector pins causing intermittent signal loss; Reluctor wheel (tone ring) damage, missing teeth, or excessive runout on the crankshaft; Metal debris stuck to the magnetic pickup of the CKP sensor; Faulty ECM driver circuit or poor ground connection at the engine block; Aftermarket flywheel or harmonic balancer with incorrect reluctor ring spacing

DTC codes / GM codes / P1335

P1335 · GMCrankshaft Positioning Sensing Circuit

Q: What does code P1335 mean?

Crankshaft Positioning Sensing Circuit. P1335 on a GM vehicle means the engine control module (ECM) has detected an implausible or missing signal from the crankshaft position (CKP) sensor circuit while the engine is running or cranking. The ECM compares the crankshaft signal with the camshaft position signal and sets this code when the expected pulses are absent, erratic, or out of sequence.

P1335 on a GM vehicle means the engine control module (ECM) has detected an implausible or missing signal from the crankshaft position (CKP) sensor circuit while the engine is running or cranking. The ECM compares the crankshaft signal with the camshaft position signal and sets this code when the expected pulses are absent, erratic, or out of sequence.

SystemPowertrain

Code typeGM specific

SeverityHigh

Fix difficultyProfessional

AreaIgnition system and misfire

Symptoms you may notice

Engine cranks but does not start, or starts only after a long crank
Intermittent stalling while driving, especially when the engine is hot
Rough running or misfire at idle and under load
Tachometer needle drops to zero or behaves erratically
Often no symptoms besides the warning light if the fault is intermittent
Reduced engine power or limp mode on some GM models

Common causes, most likely first

Failed crankshaft position sensor (CKP) due to heat, contamination, or internal winding failure
Damaged or chafed wiring between the CKP sensor and the ECM, often near exhaust manifolds or sharp brackets
Corroded or loose CKP sensor connector pins causing intermittent signal loss
Reluctor wheel (tone ring) damage, missing teeth, or excessive runout on the crankshaft
Metal debris stuck to the magnetic pickup of the CKP sensor
Faulty ECM driver circuit or poor ground connection at the engine block
Aftermarket flywheel or harmonic balancer with incorrect reluctor ring spacing

How to diagnose and fix it

Scan all modules for stored and pending codes, then record freeze-frame data for P1335 and any camshaft or misfire codes
Inspect the CKP sensor connector and wiring harness for chafing, corrosion, and loose pins, repairing as needed
Measure the CKP sensor resistance and compare to the GM specification for the engine; replace the sensor if out of range
Check the reluctor wheel for damaged or missing teeth and for excessive crankshaft end play using a dial indicator
Back-probe the CKP signal wire at the ECM and observe the AC voltage or waveform with an oscilloscope while cranking
Verify the CKP sensor air gap and mounting surface are clean and within specification
If the signal is present at the sensor but not at the ECM, test continuity and resistance on both signal and ground circuits to rule out a harness or ECM fault

What a P1335 crankshaft code really means

A P1335 can be set by a failing camshaft position sensor or a stretched timing chain because the ECM compares crank and cam signals and flags the crank circuit when the relationship is wrong.
Many technicians replace the CKP sensor only to find the real fault is a corroded ground strap at the engine block, which corrupts the signal reference voltage.
Intermittent P1335 codes that appear only when the engine is hot often point to a failing sensor winding that opens with heat, not to a wiring problem.
After a clutch or flywheel replacement, a missing or incorrectly indexed reluctor ring can set P1335 even though the sensor and wiring are perfect.
Some GM vehicles will run with a failed CKP sensor using the camshaft signal alone, so the engine may start and drive normally while P1335 is stored, leading owners to ignore a fault that will eventually cause a no-start.

Can I keep driving with P1335?

Do not continue driving with an active P1335 because the engine can stall without warning and may not restart, leaving you stranded in traffic. If the code is intermittent and the engine runs normally, drive only to a repair shop and avoid high-speed roads or heavy traffic.

Tools that help

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Guidance is general and written for GM vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.