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Mitsubishi Eclipse Cross: 4B40 Turbocharger Wastegate Actuator Position Sensor Fault (P0243 / Limp Mode)

4B40 Turbocharger Wastegate Actuator Position Sensor Fault (P0243 / Limp Mode) is a common engine fault on the Mitsubishi Eclipse Cross on the 2017 onward cars, and we rate it major. Putting it right costs $650 to $1,400 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 21 documented faults on the Mitsubishi Eclipse Cross.

Vehicle: Mitsubishi Eclipse Cross
Engine: 4B40
Years: 2017 onward
Fuel: petrol
System: Engine

This page covers the Mitsubishi Eclipse Cross as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Mitsubishi Eclipse Cross faults21 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Turbocharger yet. We would rather show none than show a picture of a different part.

What goes wrong

The 4B40 1.5-litre turbocharged engine uses an electronic wastegate actuator with an integrated position sensor. The sensor feedback signal degrades due to heat cycling and connector corrosion at the actuator harness plug, causing the ECU to log P0243 (Turbocharger Wastegate Solenoid A) and default to limp mode capping boost. In some cases the actuator motor itself seizes, requiring full actuator replacement rather than sensor-only repair.

What you would notice

Engine enters limp mode with reduced power above 2500 rpm, often triggered after a long highway run
MIL illuminated with P0243 stored; turbo boost gauge or live-data shows underboost or zero boost
Intermittent loss of power that clears after engine cool-down then returns with heat soak
Rough acceleration feel as boost cuts in and out during partial-throttle driving

How to check it

Where to look. Turbocharger wastegate actuator, passenger-side of engine bay

Scan for P0243, P0244, P0299. Live-data the wastegate actuator position versus commanded duty cycle — a stuck or erratic reading confirms the fault. Inspect the 3-pin actuator connector for green corrosion and back-probe pin voltages. Physically attempt to rotate the actuator rod by hand with ignition off; stiff or seized movement indicates actuator failure.

Parts involved: Turbocharger.

What it costs to put right

$650 to $1,400 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the check engine light ever come on, particularly after motorway driving?”
“Has the car ever gone into a low-power mode where it wouldn't accelerate past 80 km/h?”
“Has the turbo actuator or any boost-related component been replaced?”

Now check the Mitsubishi Eclipse Cross you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Mitsubishi Eclipse Cross buyer questions

Is 4b40 turbocharger wastegate actuator position sensor fault (p0243 / limp mode) serious on a Mitsubishi Eclipse Cross?

We rate it major and common on the Mitsubishi Eclipse Cross. The 4B40 1.5-litre turbocharged engine uses an electronic wastegate actuator with an integrated position sensor. The sensor feedback signal degrades due to heat cycling and connector corrosion at the actuator harness plug, causing the ECU to log P0243 (Turbocharger Wastegate Solenoid A) and default to limp mode capping boost. In some cases the actuator motor itself seizes, requiring full actuator replacement rather than sensor-only repair.

How much does it cost to fix on a Mitsubishi Eclipse Cross?

$650 to $1,400 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Mitsubishi Eclipse Cross years are affected?

Our research records this fault on the 2017 onward Mitsubishi Eclipse Cross. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.