P1512–P1513 Intake Manifold Change-Over Valve (N156) - Short to B+
A wire in this circuit is touching a live positive feed, so the part sees power when it shouldn't.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P1512 | Intake Manifold Change-Over Valve (N156) - Short to B+ | Investigate soon |
P1513 | Intake Manifold Change-Over Valve 2 (N261) - Short to B+ | Investigate soon |
The definition
P1512: Intake Manifold Change-Over Valve (N156) - Short to B+.
P1512 is a manufacturer-specific powertrain code (the engine or gearbox). Its meaning is set by the carmaker rather than by the SAE standard, so a generic OBD-II reader will often show it as an unknown code or misread it.
What to check first
Cheapest and fastest checks first:
- With the connector unplugged and ignition on, check whether the signal pin already has battery voltage on it. It should not.
- Check for a chafed wire lying against a live feed, especially in looms that run alongside the starter or alternator cabling.
What actually causes this on a VAG
Many VAG engines have a variable-length or two-stage inlet manifold - a flap inside changes the length of the inlet tracts so the engine breathes well low down and again high up the rev range. N156 is the small solenoid valve that switches the vacuum which moves that flap, and on engines fitted with two of these valves this code is the first one; the second, N261, has codes of its own. This code is purely electrical: the ECU has found the valve's circuit sitting at battery voltage when it should be being switched. The symptoms are usually mild - a soft patch in the power delivery at one end of the rev range, and the warning light on.
Most likely causes, in order
- Connector or wiring at the valve. These solenoids live in the hot part of the engine bay, and the plug and the last few centimetres of wire take the worst of the heat, oil and vibration. Unplug it and check for corroded pins, a pin pushed back in the housing, and insulation that has gone brittle and cracked where the loom is clipped down. Free to check, and the most likely answer.
- Loom chafed against a live feed elsewhere. A short to battery voltage does not have to be at the valve. Anywhere the loom is pulled tight over a stud, bracket or engine mount, the insulation can wear through and touch a permanently live wire in the same bundle. Follow the whole run, not just the end nearest the valve, and pay particular attention to any section disturbed during previous work. Still free, and it has to be ruled out before you spend anything - a new valve will not fix a chafed loom.
- The solenoid has failed. The winding inside can short or go open with age and heat, and some ECUs report an open output the same way they report a short to B+. Confirm before you buy rather than after: unplug the valve, clear the fault memory and run the engine briefly. If the same short-to-B+ fault is still reported with the valve disconnected, the fault is in the loom and the valve is innocent. If it changes to an open-circuit style fault, the wiring is doing its job and the valve is the part - a small, comparatively inexpensive component.
Worth knowing: Don't let this become a manifold replacement. A flap that is physically stuck, or a manifold whose internal linkage has broken, sets a different fault - a stuck-open, stuck-closed or implausible-signal style code, not a short to B+. All this one says is that the ECU cannot switch the valve electrically, so start at the plug and the solenoid, which cost a fraction of a manifold. Worth checking while you are there: these systems run on stored vacuum, so a perished vacuum hose or a leaking reservoir will cause flap complaints of its own, though not this code.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P1512 mean?
P1512 means Intake Manifold Change-Over Valve (N156) - Short to B+. A wire in this circuit is touching a live positive feed, so the part sees power when it shouldn't.
Can I drive with P1512?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.