P0335 on Ford: How to Diagnose & Fix
Crankshaft Position Sensor A Circuit Malfunction
1 Ford model · 1 documented issue · 1 critical · $250-$600 repair
P0335 on Ford by model: symptoms, diagnosis and fix
Owners report the Auto Start-Stop system killing the engine at traffic lights, at low speed and mid-turn, and then failing to restart — leaving the vehicle dead in a live traffic lane. A related and sometimes identical-looking complaint is a wholesale loss of electrical power while driving, with the cluster lighting up with oil pressure, ABS, check-engine and charge warnings at once before the engine dies. Dealer findings have pointed at the battery and battery monitoring sensor (Start-Stop depends on the BMS correctly modelling state of charge, so a marginal battery causes both misbehaviour and failed restarts), at loose electrical wiring and connectors, and in some cases at the crankshaft position sensor. Multiple owners report repeat visits without a durable fix, including cars that stalled again after a battery replacement and recalibration. Note that a stall accompanied by an oil-pressure warning on a 1.0L car is the oil-pump-belt failure signature and must be investigated as an engine failure, not as a Start-Stop fault.
Common Symptoms
- Engine shuts off at a stoplight and will not restart
- Stall while turning or at low speed
- Entire cluster lights up (oil, ABS, charge, check engine) then the engine dies
- 'Auto Start-Stop not ready' or the system refusing to engage
- Slow or laboured cranking
- Repeated dead battery with no obvious parasitic draw
How to Fix
Have the battery load-tested AND the battery monitoring sensor checked and recalibrated — a new battery installed without a BMS reset will reproduce the fault. Inspect the underhood and underdash grounds and connectors for looseness and corrosion, which dealers have identified as a cause of power loss in motion. Scan for stored codes rather than clearing them; crankshaft position sensor faults present the same way. Auto Start-Stop can be disabled on each key cycle via the dash button as a stopgap, but that masks a marginal battery or charging condition rather than fixing it. Battery plus BMS calibration is typically $250-$450; a CKP sensor is roughly $150-$300 fitted. If a 1.0L car stalls with a low oil pressure warning, stop driving it and check recall 23S64 / 23V905000 status immediately.
What you need to diagnose it
The repair instructions explicitly call for reading stored codes. Use a scanner that can read the named code families before choosing a repair.The recommended scanner supports these code families; confirm your exact year, model and module coverage before buying.
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Read & clear engine (P) codes
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Reading and clearing the code is DIY work. Module replacement or reprogramming is not — most modules are VIN-programmed, so a new one does nothing until a shop codes it to your car. Check for an open recall or service bulletin before buying anything.
Sources for this issue (3)
P0335 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0335 mean on a Ford?
P0335 stands for "Crankshaft Position Sensor A Circuit Malfunction." This code means the engine computer has lost or detected a faulty signal from the crankshaft position sensor (sensor A), which tells the computer exactly how fast and in what position the crankshaft is rotating. That signal is essential for timing the spark and fuel injection, so a problem here can cause hard starting, stalling, or a no-start condition. The computer sets this code when the crank sensor signal is missing, erratic, or out of its expected pattern. Causes range from a failed sensor or damaged wiring to a problem with the reluctor (tone) ring the sensor reads. On Ford it is documented across 1 model: EcoSport.
What are the most common causes of P0335?
The most common causes of P0335 are: Failed crankshaft position sensor, Damaged, corroded, or loose sensor wiring/connector, Metal debris or oil contamination on the sensor tip, Damaged or misaligned reluctor (tone) ring, Excessive air gap between sensor and tone ring, Wiring shorted or open in the sensor circuit, Faulty PCM/ECM (rare). The specific cause varies by vehicle.
How much does it cost to fix P0335 on a Ford?
Published repair estimates on Ford range from $250 to $600 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0335 on a different make?
View P0335 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.