P1328 — 6 documented meanings by make

P1328 does not mean the same thing on every car — manufacturers reuse the number for different faults. 10 makes document it: Audi, BMW, Ford, Mazda, Opel / Vauxhall, Saab, SEAT, Skoda, Volkswagen, Volvo. Find your make below.

P1328 on Audi, SEAT, Skoda, Volkswagen

On Audi, SEAT, Skoda, Volkswagen vehicles P1328 is documented as: Knock control, cylinder 4, control limit reached. P1328 is stored when the ECU sees below threshold on the circuit named in the code (cylinder 4). 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: The monitored part has degraded rather than failed; An upstream fault is loading the part beyond its design; Sensor used to judge the threshold is itself inaccurate; Normal wear reaching the end of its service life.

Check first, cheapest first:

1. Fix any other stored codes first — this class is very often a consequence, not a cause
2. Verify the sensors that judge the threshold before replacing the expensive part
3. Check for leaks or restrictions that would make a healthy part read as failed
4. Compare readings before and after the component
5. Replace the component once it is proven to be the one that has degraded

Related Audi, SEAT, Skoda, Volkswagen codes:

P1328 on BMW

On BMW vehicles P1328 is documented as: Knock sensor 2 - bank 1 high input. P1328 is stored when the ECU sees signal too high on knock sensor (bank 1, sensor 2). 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: Open ground for the sensor, letting the signal float up; Signal line shorted to a supply voltage; Sensor failed open, which the module reads as maximum; Connector fault interrupting the return path.

Check first, cheapest first:

1. Read the live value and compare with what the conditions should produce
2. Check the sensor ground continuity back to the module
3. Unplug the sensor: if the reading changes, the wiring is intact and the sensor is suspect
4. Inspect the connector for corrosion or a spread terminal
5. Replace the sensor once ground and signal wiring are confirmed good

Related BMW codes:

P1328 on Ford, Mazda

On Ford, Mazda vehicles P1328 is documented as: Cylinder 12 high to low side, open circuit. P1328 is stored when the ECU sees open circuit on the circuit named in the code (cylinder 12). 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 Ford, Mazda codes:

P1328 on Opel / Vauxhall

On Opel / Vauxhall vehicles P1328 is documented as: Knock control, maximum spark limit, cylinder 3. P1328 is stored when the ECU sees below threshold on the circuit named in the code (cylinder 3). 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: The monitored part has degraded rather than failed; An upstream fault is loading the part beyond its design; Sensor used to judge the threshold is itself inaccurate; Normal wear reaching the end of its service life.

Check first, cheapest first:

1. Fix any other stored codes first — this class is very often a consequence, not a cause
2. Verify the sensors that judge the threshold before replacing the expensive part
3. Check for leaks or restrictions that would make a healthy part read as failed
4. Compare readings before and after the component
5. Replace the component once it is proven to be the one that has degraded

Related Opel / Vauxhall codes:

P1328 on Saab

On Saab vehicles P1328 is documented as: Knock control maximum spark level cylinder 3.

Related Saab codes:

P1328 on Volvo

On Volvo vehicles P1328 is documented as: Fault in ECM knock control circuit. P1328 is stored when the ECU sees malfunction on control module. 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 or connector fault in the circuit; Component failed electrically; Supply or ground problem feeding the circuit; Controlling module fault, though this is the least common of the four.

Check first, cheapest first:

1. Read all stored codes — a general fault code is often the symptom of a more specific one
2. Inspect the connector and wiring for the named component
3. Check supply and ground at the component
4. Measure the component against specification
5. Replace the component once wiring and supply are ruled out

Related Volvo 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 P1328 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.