P1492 — 9 documented meanings by make

P1492 does not mean the same thing on every car — manufacturers reuse the number for different faults. 13 makes document it: Audi, Chrysler, Citroen, Ford, Mazda, Mitsubishi, Nissan, Peugeot, Saab, SEAT, Skoda, Subaru, Volkswagen. Find your make below.

P1492 on Audi, SEAT, Skoda, Volkswagen

On Audi, SEAT, Skoda, Volkswagen vehicles P1492 is documented as: Activated charcoal filter system solenoid 2, N333, electrical failure. P1492 is stored when the ECU sees malfunction 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 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 Audi, SEAT, Skoda, Volkswagen codes:

P1492 on Chrysler

On Chrysler vehicles P1492 is documented as: Ambient/battery temperature sensor input, voltage too high. P1492 is stored when the ECU sees signal too high on charging system. 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 Chrysler codes:

P1492 on Citroen, Mazda, Peugeot

On Citroen, Mazda, Peugeot vehicles P1492 is documented as: APLSOL solenoid circuit.

Related Citroen, Mazda, Peugeot codes:

P1492 on Ford

On Ford vehicles P1492 is documented as: Port air relief valve solenoid.

Related Ford codes:

P1492 on Mitsubishi

On Mitsubishi vehicles P1492 is documented as: Battery temperature sensor high input. P1492 is stored when the ECU sees signal too high on charging system. 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 Mitsubishi codes:

P1492 on Nissan

On Nissan vehicles P1492 is documented as: Purge control solenoid.

Related Nissan codes:

P1492 on Saab

On Saab vehicles P1492 is documented as: Evaporative emission system, fuel level sensor; Evaporative emission system, tank pressure sensor value too low. P1492 points at evaporative emissions system. 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: Fuel cap not sealing or the wrong cap fitted; Cracked or perished breather hose; Purge valve stuck open; Charcoal canister split; Leaking tank seal around the pump flange.

Check first, cheapest first:

1. Refit the fuel cap firmly, clear the code and drive for a few days — a surprising share of these are the cap
2. Inspect the visible EVAP hoses for cracks and loose clamps
3. Command the purge valve with a scanner and listen for it clicking
4. Smoke-test the system if the simple checks find nothing — a small leak is very hard to see

Related Saab codes:

P1492 on Subaru

On Subaru vehicles P1492 is documented as: Exhaust gas recirculation solenoid signal nr. 1, low input. P1492 is stored when the ECU sees signal too low on EGR system. 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: High resistance in the supply or ground path, dragging the signal down; Corroded connector adding resistance the module reads as a low reading; Sensor drifted out of tolerance with age; Partial short to ground somewhere in the signal line.

Check first, cheapest first:

1. Read the live value on a scanner and compare with a known-good reading
2. Clean and re-seat the connector, then re-test before replacing anything
3. Check the ground point for that circuit — a poor ground causes this far more often than a bad sensor
4. Measure the sensor against specification with the connector back-probed
5. Replace the sensor only once the wiring and ground have been ruled out

Related Subaru 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 P1492 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.