A starting problem accompanied by a crankshaft or camshaft code needs the exact vehicle and signal information. Changing the named sensor without checking the circuit may leave the fault unresolved. Keep the original scan and note whether the engine fails to turn, turns without starting or stops after running.
What the codes point to
P0335 concerns the crankshaft-position sensor circuit. P0340 concerns the camshaft-position sensor circuit. The wording does not identify a particular failed component.
Code descriptions: HELLA generic diagnostic-code reference. Confirm the full code, suffix and test procedure against the exact vehicle.
Sensor type changes the test method
HELLA advises identifying the sensor design before testing; appearance or a three-pin connector alone cannot reliably distinguish the sensor type. The correct specifications matter, along with checks for damaged connections, wiring and contamination. Source: HELLA crankshaft-sensor guidance.
HELLA describes the camshaft signal working with crankshaft information for engine position and control. It also lists wiring interruption and mechanical damage among possible fault areas. Source: HELLA camshaft-sensor guidance.
What a workshop report should preserve
Ask for the full codes, fault status and relevant recorded signals where available. Include the conditions under which measurements were taken. A waveform without the vehicle, sensor identification, time scale or operating state can be difficult to interpret.
Explain any recent timing work, engine replacement, sensor substitution or connector repair. If the fault is temperature-related, describe the pattern from normal use rather than repeatedly running an unreliable vehicle to provoke it. Record whether the replacement changed anything at all.
Choose electrical or mechanical assessment appropriately
A signal-circuit enquiry and a mechanical timing concern are different jobs. Ask the diagnosing garage which route its evidence supports. For wiring or controller questions, use AXION electrical diagnostics; keep the original ECU if a controller assessment is proposed.
AXION Automotive handles specialist electronics enquiries from Didcot and UK garages. Use our assessment checklist, then send the vehicle details and scan report. Vehicle and component support must be confirmed before booking or posting a unit.