P2533: Ignition Switch On/Start Position Circuit
What to do
If the engine fires and dies the instant you let the key spring back, that pattern points straight at this circuit. It is the signal that tells the module the engine should keep running across the changeover from cranking to running. Worth mentioning that it is not the same as a fuel problem, and worth trying whether releasing the key more gently changes anything. Try the spare key too — that separates an ignition switch fault from an immobiliser one, which produces a similar start-then-stall.
What this code means
A fault in the circuit reporting that the ignition is in either the run or the start position.
Why this is a separate signal from the run position at P2530 is the useful part, and it explains a specific and puzzling symptom.
During cranking the starter motor draws an enormous current, and system voltage falls sharply as a result. To give the starter as much as possible, some circuits are deliberately dropped while the key is held at start — and the plain run contact is often one of them. So during cranking, the run signal may be absent even though the engine is supposed to run.
The run-and-start line exists to cover that gap. It is live in both positions, so the module has a continuous "you should be running" signal across the whole start event, including the moment the key springs back from start to run.
Which produces the characteristic failure: an engine that fires and immediately dies as the key is released. It catches, runs for a fraction of a second, and stops as the key returns — because the module momentarily has neither signal and concludes it should shut down. That pattern is distinctive enough to point here directly, and it is frequently mistaken for a fuel delivery or immobiliser fault. The corpus notes at the immobiliser that a start-then-stall pattern is characteristic of that too, so the two are worth separating: an immobiliser fault usually behaves identically with every attempt, while a switch fault often responds to how the key is turned or released.
Likely causes
Start here
- Worn ignition switch contacts · moderate
- Faulty ignition switch · moderate
- Corroded or loose connector · easy
Less common
- Damaged wiring harness · moderate
- Failed starter relay · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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