BatteryHigh
PHEV drive battery capacity down, shorter electric range than claimed
- Typically appears
- 60,000+ miles
- What to inspect
- Charge fully and check the EV range readout against the original figure, then read cell balance on a diagnostic
MI
2012–2021 Mitsubishi Outlander · common problems & known faults
A practical seven-seat SUV and the UK's best-selling plug-in hybrid for years, but the PHEV drive battery, brake system and 12V electrics are where the money hides.
Compiled & reviewed by the VehicleFaults Research Team · last reviewed August 2026
Quick answer
The most commonly reported faults on the 2012–2021 Mitsubishi Outlander are PHEV drive battery capacity down, shorter electric range than claimed, Diesel DPF blocking on short urban runs and No cabin heat when running in pure EV mode due to a failed electric PTC heater element. 3 of the documented issues are rated high severity · inspect these first. Full inspection points, onset mileage and what to check are listed below.
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Build the inspection planReliability snapshot
Based on the documented faults on this page for the Mitsubishi Outlander.
3.9/ 10
- Critical
- 0
- High
- 3
- Medium
- 5
- Low
- 0
Guidance only · reflects reported patterns, not a specific car's condition.
Known faults to check
ElectricalMedium
12V battery flattening when the car sits, refusing to wake the hybrid system
- Typically appears
- Age-related
- What to inspect
- Leave the car locked for an hour then check it starts and the charge timer works
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Build the inspection planBrakesMedium
Rear discs corroding early because regen does most of the braking
- Typically appears
- 40,000+ miles
- What to inspect
- Inspect rear discs for lipping and heavy surface rust, and feel for pulsing under braking
EngineHigh
Diesel DPF blocking on short urban runs
- Typically appears
- 50,000+ miles
- What to inspect
- Check for repeated regeneration attempts in the service history and warning lights on a cold start
SuspensionMedium
Front lower arm bushes knocking over broken surfaces
- Typically appears
- 60,000+ miles
- What to inspect
- Listen for clonks over speed bumps and check for uneven front tyre wear
HVACHigh
No cabin heat when running in pure EV mode due to a failed electric PTC heater element.
- Typically appears
- 50,000-80,000 miles
- What to inspect
- Turn the car to 'Ready' mode with sufficient battery. Set climate control to maximum heat, turn off AC, and ensure the petrol engine hasn't started. Feel the vents for hot air after 60 seconds.
Body / ElectricalMedium
Front wipers stop working or operate erratically due to water ingress into the motor or the linkage ball joint failing.
- Typically appears
- 40,000-70,000 miles
- What to inspect
- Operate the front wipers on all speed settings. Listen for grinding noises from the scuttle panel and check for excessive play by gently lifting the wiper arms while they are parked.
Engine (2.2 DI-D)Medium
Loss of power, engine management light illuminated, and a loud hissing noise under acceleration caused by a split top intercooler hose.
- Typically appears
- 60,000-100,000 miles
- What to inspect
- Open the bonnet and locate the large rubber boost hose leading to the throttle body at the top front of the engine. Squeeze it and feel the underside for oily residue or visible splits.
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Build my inspection planFrequently asked questions
Is the Outlander PHEV battery expensive to replace?
A full pack replacement is one of the biggest costs on the car, so a battery health report matters more than mileage.
Why do the rear brakes rust?
Regenerative braking means the rear pads rarely bite hard, so discs corrode rather than wear.
Is the diesel a safer buy?
Only for high-mileage motorway use; on short trips the DPF causes more trouble than the PHEV.
What service history should I look for?
Annual servicing plus evidence the hybrid system and brake fluid have been checked.
Why does the PHEV petrol engine start even when the battery is fully charged?
The internal combustion engine will automatically engage under heavy acceleration, at higher motorway speeds, or if the climate control demands sudden heat. The system also forces the engine to run periodically to prevent petrol going stale and to lubricate internal components if the vehicle is driven exclusively in EV mode.
What causes the power tailgate to beep but fail to open?
This is typically caused by failing gas struts that can no longer support the weight of the boot lid, which triggers the anti-pinch safety mechanism. It can also result from a misaligned latch. Replacing the gas struts usually resolves the issue and restores normal electronic operation.
Sources & further reading
Faults are compiled from documented recalls, technical bulletins, owner reports and mechanic sources, then reviewed for accuracy. This is guidance only · not a substitute for a professional inspection.
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