P1577 — 13 documented meanings by make

P1577 does not mean the same thing on every car — manufacturers reuse the number for different faults. 15 makes document it: Audi, Chevrolet (USA), Citroen, Ford, Honda, Jaguar, Mazda, Opel / Vauxhall, Peugeot, Saab, SEAT, Skoda, Subaru, Toyota, Volkswagen. Find your make below.

P1577 on Audi, SEAT, Skoda, Volkswagen

On Audi, SEAT, Skoda, Volkswagen vehicles P1577 is documented as: Right electrohydraulic engine mounting solenoid, N145, open circuit. P1577 is stored when the ECU sees open circuit on the circuit named in the code (right). 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 Audi, SEAT, Skoda, Volkswagen codes:

P1577 on Chevrolet (USA)

On Chevrolet (USA) vehicles P1577 is documented as: Brake booster vacuum sensor circuit, low voltage. P1577 is stored when the ECU sees signal too low 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: 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 Chevrolet (USA) codes:

P1577 on Citroen, Jaguar, Peugeot

On Citroen, Jaguar, Peugeot vehicles P1577 is documented as: Pedal position sensor disagreement between sensors. P1577 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 Citroen, Jaguar, Peugeot codes:

P1577 on Ford

On Ford vehicles P1577 is documented as: Pedal position sensor outputs disagree. P1577 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 codes:

P1577 on Honda

On Honda vehicles P1577 is documented as: High voltage detection signal circuit. P1577 is stored when the ECU sees signal too high 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: 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 Honda codes:

P1577 on Mazda

On Mazda vehicles P1577 is documented as: Accelerator pedal position sensor output incongruent. P1577 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 Mazda codes:

P1577 on Opel / Vauxhall

On Opel / Vauxhall vehicles P1577 is documented as: Exhaust brake valve 2, open circuit; Exhaust brake valve 2, short circuit. P1577 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 Opel / Vauxhall codes:

P1577 on Saab

On Saab vehicles P1577 is documented as: Brake light switch, open circuit; Brake light switch, short circuit to ground; Brake light switch, short circuit to positive. P1577 is stored when the ECU sees open circuit on brake switch. 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:

P1577 on Subaru

On Subaru vehicles P1577 is documented as: IMM control unit EEPROM. P1577 points at control module. The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.

Related Subaru codes:

P1577 on Toyota

On Toyota vehicles P1577 is documented as: Steering angle sensor. P1577 points at steering. The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.

Related Toyota 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 P1577 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.