2021 Citroen C4 diesel: common problems and MOT failures

What goes wrong more than usual on a 2021 Citroen C4 diesel?

Parts flagged at MOT more often on the 2021 Citroen C4 diesel than on all cars registered in 2021.

• Brake discs2.4× usual
  Citroen C4

  14.2% All 2021 cars

  6%

  Failed outright at MOT: 0.5%, against 0.3% of all 2021 cars. The rest were advisories or minor defects.

  Rough price £150–£350 our estimate

  At the viewing: Look through the wheel at the brake disc: a deep lip at the edge or heavy scoring means they're worn. Feel for judder when braking.

Common 2021 Citroen C4 diesel MOT failures and advisories

The share of 2021 Citroen C4 diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• Tyres
  22% of testsRough price £70–£150

  At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

• Brakes
  19% of testsRough price £150–£350

  At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

• Wipers, windscreen and mirrors
  7% of testsRough price £15–£250

  At the viewing: Check for chips in the driver's view, and test the wipers and washers.

• Suspension
  6% of testsRough price £120–£400

  At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

• Seats and seatbelts
  3% of testsRough price £80–£250

  At the viewing: Pull each seatbelt sharply. It should lock, and retract cleanly.

• Lights and electrics
  3% of testsRough price £10–£80

  At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

Known faults on the 2021 Citroen C4 diesel

Reported by owners, mechanics and buying guides for this model and age. Check which engine the car has, as some apply to one engine only.

• Air-con wiring recall can shut down the powertrain

  Cars built Jul-Nov 2022

  A May 2023 recall covered 6,867 vehicles built from July to November 2022. Faulty wiring to the air-con compressor could make the whole powertrain shut down. The fix is a software update to the powertrain diagnosis control unit.

  At the viewing: Check the build date. For cars built July-November 2022, confirm the recall is done using Citroen's online recall checker.

  Source: Auto Express: used Citroen C4 Mk3 (2020-date) review

• Cambelt due at 10 years or 116,000 miles

  Petrol and diesel engines

  The petrol and diesel engines use a cambelt, which needs changing every 10 years or 116,000 miles at a cost of about £499.

  At the viewing: Check the service history for the cambelt change on high-mileage cars, or budget for it.

  Source: Auto Express: used Citroen C4 Mk3 (2020-date) review

Questions to ask the seller before buying a 2021 Citroen C4 diesel

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

1. If the car was built between July and November 2022, has the air-con wiring recall software update been done?
2. Any recent work on the brake discs? (Flagged at MOT 2.4× as often on the 2021 Citroen C4 diesel as on other cars the same age.)
3. Can I see the service history and receipts for any big jobs?