P1972 — 2 documented meanings by make

P1972 does not mean the same thing on every car — manufacturers reuse the number for different faults. 5 makes document it: Audi, Mitsubishi, SEAT, Skoda, Volkswagen. Find your make below.

P1972 on Audi, SEAT, Skoda, Volkswagen

On Audi, SEAT, Skoda, Volkswagen vehicles P1972 is documented as: Secondary air pump relay 4, J705, short circuit to ground. P1972 is stored when the ECU sees short to ground on secondary air injection. 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:

P1972 on Mitsubishi

On Mitsubishi vehicles P1972 is documented as: Inquiry/response error.

Related Mitsubishi 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 P1972 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.