P1338–P1392 Camshaft Position Sensor (G40), Bank 1: Open Circuit/Short to B+
A wire in this circuit is touching a live positive feed, so the part sees power when it shouldn't.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P1338 | Camshaft Position Sensor (G40), Bank 1: Open Circuit/Short to B+ | Investigate soon |
P1392 | Camshaft Position Sensor (G163), Bank 2: Open Circuit/Short to B+ | Investigate soon |
The definition
P1338: Camshaft Position Sensor (G40), Bank 1: Open Circuit/Short to B+.
P1338 is a manufacturer-specific powertrain code (the engine or gearbox). Its meaning is set by the carmaker rather than by the SAE standard, so a generic OBD-II reader will often show it as an unknown code or misread it.
What to check first
Cheapest and fastest checks first:
- With the connector unplugged and ignition on, check whether the signal pin already has battery voltage on it. It should not.
- Check for a chafed wire lying against a live feed, especially in looms that run alongside the starter or alternator cabling.
What actually causes this on a VAG
G40 is the camshaft position sensor - a small Hall sensor at the cylinder head that watches a toothed wheel or lobe on the camshaft, so the ECU knows which cylinder is on its firing stroke. This code says the ECU is receiving nothing from it, or a signal stuck permanently at supply voltage. That is an electrical fault in the sensor's circuit, not a mechanical one. Typically you get long cranking (worst when the engine is hot), the odd refusal to start, and an engine that then runs on the crankshaft sensor alone with fuelling and timing less precise - and on an engine with variable valve timing, cam adjustment shut down as well, which makes it feel noticeably duller.
Most likely causes, in order
- Oil or heat damage in the sensor's connector. The plug sits right at the cylinder head where it bakes, and if the sensor's O-ring or the cam cover gasket leaks, engine oil wicks along the wires and fills the connector. Unplug it and look for oil inside the plug body and for blackened or green pins. Cleaning or renewing the connector cures a good number of these on its own.
- The sensor itself has failed. Hall sensors are a routine failure item on VAG engines and commonly go open circuit as they die. If the plug is clean and dry, the supply and earth are present, and there is still no signal while cranking, the sensor is the part.
- Chafed or heat-hardened wiring to the ECU. The short run of loom across the head suffers from constant heat cycling until the insulation cracks, and it chafes where it passes a strut brace, a coolant pipe or a bracket. Wiggle-test it with the ignition on while watching the fault memory, and pay particular attention to any section that has been disturbed at a service.
Worth knowing: Read this one literally - it is an electrical fault in the sensor circuit. It is not the code a stretched timing chain or a slipped belt produces; those show up as camshaft-to-crankshaft correlation faults such as P0016, usually alongside other codes and a car that runs badly or not at all. If a garage quotes a timing job on the strength of a P1338 alone, ask to see a correlation code or a live timing measurement first. And if you find oil inside the sensor's plug, fix whatever is leaking at the same time, or the new sensor will be ruined the same way.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P1338 mean?
P1338 means Camshaft Position Sensor (G40), Bank 1: Open Circuit/Short to B+. A wire in this circuit is touching a live positive feed, so the part sees power when it shouldn't.
Can I drive with P1338?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.