What Does P0335 Mean?
The ECM is not receiving a valid signal from the crankshaft position (CKP) sensor A. This sensor is critical for determining engine RPM and crankshaft position for ignition timing and fuel injection. Without a CKP signal, the engine may crank but not start, stall intermittently, or exhibit severe misfires since the ECM cannot synchronize spark and fuel delivery.
Safety Warning
Do not drive if the engine stalls or fails to start reliably. A complete CKP signal loss causes a no-start condition. Intermittent CKP failures can cause sudden engine stalling at any speed, including highway driving, creating a serious safety hazard with loss of power steering and reduced brake assist. Have the vehicle towed if stalling is occurring.
Common Causes
40%
Failed crankshaft position sensor (internal open circuit or dead Hall-effect/reluctance element)
25%
Damaged or corroded wiring or connector in the CKP sensor circuit causing signal loss
15%
Damaged or missing teeth on the crankshaft reluctor ring (tone wheel) preventing proper signal generation
10%
Excessive air gap between CKP sensor and reluctor ring due to sensor mounting issue or ring wobble
10%
ECM driver circuit failure for the CKP sensor input
Diagnostic Steps
1
Check for engine RPM reading on live data while cranking — a reading of 0 RPM during cranking confirms total CKP signal loss; an erratic reading suggests intermittent signal.
2
Inspect the CKP sensor connector for oil contamination, corrosion, or damaged pins — the sensor location near the crankshaft pulley makes it prone to oil leaks and road debris.
3
Measure CKP sensor resistance (for magnetic type): typically 200–2,000 ohms depending on manufacturer; infinite resistance indicates an open sensor. For Hall-effect sensors, verify 5V reference and ground are present at the connector.
4
With the sensor removed, inspect the reluctor ring through the sensor bore for damaged, chipped, or missing teeth using a borescope or small mirror — any tooth damage will cause signal errors.
5
Check the sensor mounting and air gap — most CKP sensors require 0.5–1.5mm clearance to the reluctor ring; excessive gap produces a weak or no signal.
6
If the sensor and wiring test good, use an oscilloscope on the signal wire while cranking to verify a clean, consistent waveform pattern — irregular or missing pulses indicate a reluctor ring or intermittent wiring issue.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The ECM is not receiving a valid signal from the crankshaft position (CKP) sensor A. This sensor is critical for determining engine RPM and crankshaft position for ignition timing and fuel injection. Without a CKP signal, the engine may crank but not start, stall intermittently, or exhibit severe mi...
The most common cause of P0335 (Crankshaft Position Sensor A Circuit Malfunction) is: Failed crankshaft position sensor (internal open circuit or dead Hall-effect/reluctance element)
Typical repair costs for P0335 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Do not drive if the engine stalls or fails to start reliably. A complete CKP signal loss causes a no-start condition. Intermittent CKP failures can cause sudden engine stalling at any speed, including highway driving, creating a serious safety hazard with loss of power steering and reduced brake assist. Have the vehicle towed if stalling is occurring.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0335 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Generic (SAE)
Recommended Tools
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