P0246
PowertrainTurbocharger/Supercharger Wastegate Solenoid "A" High
The ECU watches the voltage on the control wire feeding the turbo wastegate solenoid, and when that voltage reads too high (or the circuit shows too much resistance) it logs P0246. For you as the driver, it means the computer has lost reliable control of the valve that manages boost pressure, so the turbo can't be told when to dump excess pressure. Most of the time this is an electrical fault in the solenoid or its wiring rather than the turbo itself being knackered.
ⓘ Information only. This page provides general educational information about fault code P0246. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0246 mean?
P0246 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Turbocharger/Supercharger Wastegate Solenoid "A" High.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine warning light on, usually the first thing you notice
- • Noticeable drop in power, the car feels flat when you put your foot down
- • Sluggish pulling on hills and slow to respond when overtaking on the motorway
- • Worse fuel economy because the boost isn't being controlled properly
- • Limp mode kicking in on some cars to protect the turbo, which caps your speed and revs
- • Occasional overboost or underboost depending on how the valve fails
Possible causes
Causes commonly associated with P0246, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Damaged or chafed wiring in the wastegate solenoid harness, often where the loom rubs against a heat shield or bracket near the turbo
- 2. Corroded or loose connector at the solenoid, very common on diesels where the plug sits low and cops road spray
- 3. The wastegate solenoid itself has failed internally with an open circuit or sky-high resistance
- 4. Water or muck getting into the connector terminals, which throws the readings off
- 5. A short to voltage somewhere in the control circuit wiring
- 6. Faulty ECM, which does happen but it's well down the list and worth ruling everything else out first
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Pull the codes and freeze frame data so you can see what the engine was doing when it logged. Note any boost-related codes sitting alongside it
- 2. Get your hands on the solenoid connector and wiring and have a proper look. Green crusty terminals, a loose plug, or chafed insulation will often show you the fault straight away
- 3. With the ignition on, check you've got the right supply voltage at the solenoid connector against the spec for that vehicle
- 4. Measure the solenoid resistance with a multimeter and compare it to the workshop figure. A typical solenoid sits in the region of a few to twenty ohms, so an open circuit or a wildly high reading points to the part
- 5. Check continuity and look for shorts right through the control circuit wiring back towards the ECU
- 6. Clear the code and take it for a road test under boost to see whether it comes back
Common questions about P0246
If I clear the code, will it stay gone? +
If the cause is a genuine electrical fault, which is the usual story with P0246, clearing it just turns the light off for a bit. It'll be back as soon as the ECU sees that high voltage again, often within a few miles of driving under boost. The only time clearing it sticks is if you've already sorted a loose connector or dodgy bit of wiring. Treat a code that keeps returning as confirmation the fault is real, not intermittent.
What am I risking if I just keep driving on it? +
You're driving with no proper control over boost. If the wastegate ends up stuck the turbo can overboost or underboost, and sustained overboost is the one that does damage to the turbo internals over time. Immediate blow-ups are uncommon, but you're gambling the longer you leave it. You'll also be putting up with reduced power and worse economy the whole time, and on many cars it'll drop into limp mode anyway.
How quickly do I need to sort this? +
It's not a roadside emergency, but don't sit on it for weeks. Book it in within the next few days, especially if the car keeps going into limp mode or you can feel a clear lack of boost. The sooner you confirm whether it's wiring or the solenoid, the smaller the chance of it leading to turbo wear that costs you a lot more than the original repair.
Is it the solenoid itself or the wiring to it? +
Could be either, and that's exactly what the diagnosis is for. Wiring and connector faults are very common with this code because the harness lives in a hot, dirty, vibration-heavy part of the engine bay. Check the connector and loom before you condemn the solenoid. Cleaning a corroded plug might cost you next to nothing, whereas a new solenoid is typically a low to mid three-figure job fitted depending on the car and how buried it is. A main dealer chasing a wiring fault by labour time can push that higher.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →