P1342
Ignition Coil Power Output State 1 Short To B+.
- Volkswagen
- Powertrain
- Manufacturer code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 1
- Defined byThe manufacturer
- 3
- AreaIgnition system or misfire
- 42
- FaultThe specific fault in that area
What it means
P1342 on a Volkswagen means the engine control unit has detected that the ignition coil power output stage for cylinder bank or channel 1 is shorted to battery positive (B+). The control unit monitors the feedback from the coil driver circuit and sees a voltage level that matches a short to supply rather than a normal switching signal. The exact coil layout and wiring depend on the model and engine, so confirm against the wiring diagram for the vehicle.
Symptoms
- Engine management light on
- Misfire or rough running, especially on one cylinder
- Hesitation or reduced power
- Hard starting or no start
- Engine running in a reduced-performance mode
Possible causes
- Faulty ignition coil or integrated driver stage with an internal short to supplylikely
- Damaged wiring to the coil control or supply circuit shorted to B+ (chafed loom, rubbed insulation)likely
- Corroded, damaged or contaminated coil connector causing a bridged circuitpossible
- Water or oil ingress into the coil connector or coil wellpossible
- Previous repair or aftermarket wiring error that has crossed the coil circuits with a live feedpossible
- Fault inside the engine control unit output stagerare
How to diagnose
- Read all stored codes and freeze frame data, noting engine load, temperature and whether other misfire codes are present
- Visually inspect the coil connector, loom and surrounding area for chafing, heat damage, oil, water and corrosion
- Check the coil connector pins for tension, green deposits and bent or pushed-back terminals
- Swap the suspect coil with another cylinder's coil, clear the code and see whether the fault follows the coil (where the engine layout allows)
- With the ignition off and the connector unplugged, check the coil control wire for continuity and for any short to battery positive using the wiring diagram
- Check the coil supply and earth feeds for correct voltage and a good connection
- Inspect spark plugs for condition and correct type, as worn plugs can stress the coil
- If wiring and coil check out, have the control unit output tested following the manufacturer's procedure
How to fix
- Replace the faulty ignition coil, and consider the plugs at the same time if they are worn
- Repair or replace the damaged section of wiring, using correct insulation and routing
- Clean or replace the corroded connector or terminals and seal against moisture
- Dry out and cure the source of water or oil ingress, such as a leaking valve cover seal or plug well seal
- Correct any faulty previous repair or wiring modification back to the original wiring diagram
- Replace or repair the engine control unit only after all wiring and coil faults have been ruled out
Can I keep driving?
The car can usually be driven short distances, but a persistent misfire can overheat and damage the catalytic converter, so get it fixed soon. If the engine is misfiring badly or the warning light flashes, stop and avoid heavy throttle.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.