P1238 — 13 documented meanings by make

P1238 does not mean the same thing on every car — manufacturers reuse the number for different faults. 15 makes document it: Audi, Citroen, Ford, Honda, Jaguar, Mazda, Peugeot, Porsche, Saab, SEAT, Skoda, Subaru, Toyota, Volkswagen, Volvo. Find your make below.

P1238 on Audi, SEAT, Skoda, Volkswagen

On Audi, SEAT, Skoda, Volkswagen vehicles P1238 is documented as: Injector cylinder 2, N31, open circuit. P1238 is stored when the ECU sees open circuit on fuel injector (cylinder 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: 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:

P1238 on Citroen

On Citroen vehicles P1238 is documented as: Fuel pump secondary circuit. P1238 points at fuel supply. 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 filter blocked; Pump worn and no longer making pressure; Pressure regulator faulty; Wiring or relay fault to the pump; Blocked strainer in the tank.

Check first, cheapest first:

1. Measure actual fuel pressure against specification — this code is about pressure, so guessing without a gauge wastes parts
2. Replace the fuel filter if it is due; it is the cheapest thing in the circuit
3. Check the pump relay and its supply voltage
4. Listen for the pump priming when the ignition is switched on
5. Replace the pump once the filter, wiring and regulator are ruled out

Related Citroen codes:

P1238 on Ford

On Ford vehicles P1238 is documented as: VSV 3 (release) circuit; Fuel pump secondary circuit (fuel pump driver module).

Related Ford codes:

P1238 on Honda

On Honda vehicles P1238 is documented as: Boost pressure control, open circuit. P1238 is stored when the ECU sees open circuit on turbocharger or boost control. 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 Honda codes:

P1238 on Jaguar

On Jaguar vehicles P1238 is documented as: VSV 3 circuit.

Related Jaguar codes:

P1238 on Mazda

On Mazda vehicles P1238 is documented as: Fuel pump primary circuit. P1238 points at fuel supply. 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 filter blocked; Pump worn and no longer making pressure; Pressure regulator faulty; Wiring or relay fault to the pump; Blocked strainer in the tank.

Check first, cheapest first:

1. Measure actual fuel pressure against specification — this code is about pressure, so guessing without a gauge wastes parts
2. Replace the fuel filter if it is due; it is the cheapest thing in the circuit
3. Check the pump relay and its supply voltage
4. Listen for the pump priming when the ignition is switched on
5. Replace the pump once the filter, wiring and regulator are ruled out

Related Mazda codes:

P1238 on Peugeot

On Peugeot vehicles P1238 is documented as: Fuel Pump Driver Module Off Line. P1238 points at fuel supply. 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 filter blocked; Pump worn and no longer making pressure; Pressure regulator faulty; Wiring or relay fault to the pump; Blocked strainer in the tank.

Check first, cheapest first:

1. Measure actual fuel pressure against specification — this code is about pressure, so guessing without a gauge wastes parts
2. Replace the fuel filter if it is due; it is the cheapest thing in the circuit
3. Check the pump relay and its supply voltage
4. Listen for the pump priming when the ignition is switched on
5. Replace the pump once the filter, wiring and regulator are ruled out

Related Peugeot codes:

P1238 on Porsche

On Porsche vehicles P1238 is documented as: Injector circuit, cylinder 2. P1238 points at fuel injector (cylinder 2). The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.

Related Porsche codes:

P1238 on Saab

On Saab vehicles P1238 is documented as: Injector circuit cylinder 2, open or short circuit to ground. P1238 is stored when the ECU sees short to ground on fuel injector (cylinder 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: 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 Saab codes:

P1238 on Subaru

On Subaru vehicles P1238 is documented as: Exhaust emission valve positive pressure solenoid circuit (high). P1238 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 Subaru codes:

P1238 on Toyota

On Toyota vehicles P1238 is documented as: Injector. P1238 points at fuel injector. 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:

P1238 on Volvo

On Volvo vehicles P1238 is documented as: Turbo control valve.

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 P1238 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.