P033F

What it means

P033F is a generic powertrain code meaning the engine control unit has detected that the crankshaft and camshaft position signals have lost their expected relationship, so engine timing cannot be trusted. The ECU compares the pattern from the crankshaft sensor with the camshaft sensor signal and sets the code when they fall out of step with each other. The exact strategy and tolerance vary by manufacturer and engine.

Symptoms

• Engine cranks but is slow to start or fails to start
• Rough running, misfire or hesitation
• Loss of power or limp mode
• Engine cutting out while driving
• Check engine light on, possibly flashing if misfire is present
• Poor fuel economy or erratic idle

Possible causes

• Faulty or contaminated crankshaft or camshaft position sensorlikely
• Damaged wiring, poor connectors or a bad earth affecting the sensor signalslikely
• Stretched or worn timing chain or belt, or tensioner and guide wear, putting timing outlikely
• Timing belt or chain fitted one tooth or more out after earlier repairpossible
• Damaged or loose reluctor wheel or trigger wheel, or a worn variable valve timing phaserpossible
• Low battery voltage during cranking causing signal dropoutspossible
• Fault within the engine control unitrare

How to diagnose

1. Read all stored and pending codes and record the freeze frame data, noting engine speed, load and temperature when the fault set
2. Check battery condition and charging voltage, as low voltage can corrupt sensor signals
3. Inspect the crankshaft and camshaft sensor wiring and connectors for chafing, oil ingress, corrosion and loose pins
4. Inspect the sensors for damage, metal debris and correct fitting, and check the air gap where the design requires it
5. Compare live crankshaft and camshaft signal data, and view both waveforms on an oscilloscope if available, checking for dropouts or a shifted relationship
6. Check cam timing correlation against the manufacturer's timing marks and specification, and look at timing chain stretch data if the model supports it
7. Inspect the trigger wheels and the variable valve timing components for damage or excessive play, following model-specific procedures
8. Check for related codes such as misfire or camshaft position correlation faults, which may point toward the cause

How to fix

• Replace the faulty crankshaft or camshaft sensor and clear the code once repaired
• Repair damaged wiring, connectors or earths found during inspection
• Replace the timing chain, tensioners and guides, or the timing belt and associated parts, and set the timing exactly to specification
• Correct incorrectly set timing and check for any resulting engine damage
• Replace a damaged trigger wheel or a faulty variable valve timing component as diagnosed
• Repair the battery or charging system if low voltage is confirmed

Can I keep driving?

Nearby codes

• P033EGenericKnock/Combustion Vibration Sensor D Circuit Intermittent
• P0340GenericCamshaft Position Sensor A Circuit Bank 1 or Single Sensor