P1343 — 6 documented meanings by make

P1343 does not mean the same thing on every car — manufacturers reuse the number for different faults. 9 makes document it: Audi, BMW, Ford, Mazda, Opel / Vauxhall, Saab, SEAT, Skoda, Volkswagen. Find your make below.

P1343 on Audi, SEAT, Skoda, Volkswagen

On Audi, SEAT, Skoda, Volkswagen vehicles P1343 is documented as: Ignition output 2, short circuit to ground. P1343 is stored when the ECU sees short to ground on the circuit named in the code. That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.

Usually one of: Wiring insulation chafed through where the loom passes a bracket or edge; Water or salt in a connector bridging the signal pin to the body; The component itself shorted internally; A harness pinched during earlier repair work.

Check first, cheapest first:

1. Unplug the component and re-read the code — if it changes, the fault is in the component, not the wiring
2. Inspect the loom where it passes metal edges, brackets and hinges
3. Open the connector and check for green corrosion or moisture
4. Measure resistance from the signal pin to a body ground; near-zero confirms the short
5. Repair the harness section, or replace the component if it shorted internally

Related Audi, SEAT, Skoda, Volkswagen codes:

P1343 on BMW

On BMW vehicles P1343 is documented as: Misfire cylinder 1 with fuel cut-off. P1343 points at engine misfire (cylinder 1). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.

Usually one of: Worn or fouled spark plugs; Failed ignition coil on that cylinder; Injector blocked or leaking; Loss of compression — worn valve or head gasket; Unmetered air leaking into the intake.

Check first, cheapest first:

1. Swap the coil with a neighbouring cylinder and see whether the misfire follows it — this identifies a coil fault in minutes and costs nothing
2. Pull the plug on that cylinder and read its condition
3. Swap the injector the same way if the misfire stayed put
4. Check for vacuum leaks around the intake
5. Compression-test the cylinder if the electrical and fuel sides are both good

Related BMW codes:

P1343 on Ford, Mazda

On Ford, Mazda vehicles P1343 is documented as: Accelerator pedal position sensor B circuit. P1343 points at accelerator pedal sensor. The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.

Related Ford, Mazda codes:

P1343 on Opel / Vauxhall

On Opel / Vauxhall vehicles P1343 is documented as: Cylinder 3 misfire detected. P1343 points at engine misfire (cylinder 3). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.

Usually one of: Worn or fouled spark plugs; Failed ignition coil on that cylinder; Injector blocked or leaking; Loss of compression — worn valve or head gasket; Unmetered air leaking into the intake.

Check first, cheapest first:

1. Swap the coil with a neighbouring cylinder and see whether the misfire follows it — this identifies a coil fault in minutes and costs nothing
2. Pull the plug on that cylinder and read its condition
3. Swap the injector the same way if the misfire stayed put
4. Check for vacuum leaks around the intake
5. Compression-test the cylinder if the electrical and fuel sides are both good

Related Opel / Vauxhall codes:

P1343 on Saab

On Saab vehicles P1343 is documented as: Ionization signal or trigg, coil 3 to CDM, open circuit; Ionization signal or trigg, coil 3 to CDM, short circuit. P1343 is stored when the ECU sees open circuit on the circuit named in the code. That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.

Usually one of: Broken wire, most often at a flex point such as a door hinge or engine mount; Corroded or pushed-back terminal in the connector; Blown fuse on the supply side; Component failed with an internally open winding or element.

Check first, cheapest first:

1. Check the relevant fuse first — it is the cheapest thing that produces this code
2. Unplug and inspect both halves of the connector for corrosion and terminal fit
3. Continuity-test the wire end to end while flexing the loom by hand
4. Measure the component itself against its specification
5. Repair the break or replace the component, whichever the measurement points to

Related Saab codes:

Which one is yours

A generic OBD reader gives you the number, not which of these meanings your manufacturer assigned to it. To get to the specific one:

1. Use a brand-specific scanner — VCDS for VAG, INPA or ISTA for BMW, XENTRY for Mercedes, Forscan for Ford. It shows the manufacturer's own text rather than the generic one.
2. Read all stored codes together — the neighbouring ones usually point at which system is involved and narrow the list.
3. Check freeze-frame data: the RPM, temperature and load at the moment it triggered indicate which system was active.
4. If you have no brand scanner, tell me the make and model below and I will tell you which of these applies to your car.

Code family

P1xxx is manufacturer-specific code (VW/Audi, BMW, Mercedes, Toyota etc. have different meanings for the same code number).

Severity

Manufacturer-specific codes need a brand scanner (VCDS for VAG, INPA for BMW, STAR for Mercedes).

That is what holds for P1343 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.