P1342–P1346 Ignition Coil Power Output Stage 1: 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 |
|---|---|---|
P1342 | Ignition Coil Power Output Stage 1: Short to B+ | Investigate soon |
P1344 | Ignition Coil Power Output Stage 2: Short to B+ | Investigate soon |
P1346 | Ignition Coil Power Output Stage 3: Short to B+ | Investigate soon |
The definition
P1342: Ignition Coil Power Output Stage 1: Short to B+.
P1342 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
The power output stage is the transistor that switches the ignition coil - built into the coil itself or the ECU on modern VAG engines, and into a separate amplifier module on older ones. 'Short to B+' means the ECU saw that coil's control line sitting at battery voltage when it should have been switched, so it disabled the output. On most engines with a coil per cylinder, stage 1 is the driver for cylinder 1, though some older engines run one stage for a pair of cylinders - worth confirming before anything comes off. In practice you'll usually have a misfire on that cylinder, a warning light and reduced power.
Most likely causes, in order
- Oil or water in the spark plug well. On many VAG engines the cam cover gasket and spark plug tube seals eventually leak, filling the plug wells with oil, and damp can get in from above as well. Oil and moisture track between the connector pins and the ECU reads the control line as pulled high. Lift the coil out and look straight down the well - what you find there is usually the answer.
- Coil breaking down internally. A failing coil can present as either kind of short depending on how it fails. Swap it with the coil from a neighbouring cylinder, clear the code and re-test: if the fault moves cylinder, the coil is at fault, and if it doesn't, stop buying coils.
- Chafed loom touching a live feed. The coil harness sits on top of a hot engine and the insulation goes brittle, so a control wire can end up touching the coils' own supply or another permanent live. Check every point where the loom crosses metal or has been pulled tight, especially after recent engine work.
- ECU internal driver stage. The output transistor inside the ECU can fail, but it's the last conclusion rather than the first. Only consider it once the plug wells, connectors, coil and loom have all been checked and cleared.
Worth knowing: If you find oil in the plug wells, fix the leak - cam cover gasket or plug tube seals - at the same time as the coil. Fitting a new coil into an oil-filled well simply buys you the same fault again in a few months, at full price. And if the engine warning light is flashing rather than steady, don't keep driving: that means a misfire severe enough to damage the catalytic converter.
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 P1342 mean?
P1342 means Ignition Coil Power Output Stage 1: 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 P1342?
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.