KNOWN FAULTS · Renault

Renault Mégane (IV) 1.5 dCi / Blue dCi (K9K) common problems.

2016–2023 · Diesel

Sources are not verified in real time and no entry confirms that your car is affected.

3 known faults with sources

Applies if: Only Euro 6b 1.5 dCi (not the later Blue dCi), if the symptoms began after the 2024 update.

Judder and flat spots when accelerating on Euro 6b 1.5 dCi and 1.6 dCi engines after the 2024 emissions updateExhaust and emissions

Engine / equipment: Renault and Dacia Euro 6b 1.5 dCi (K9K) and 1.6 dCi (R9M)
Period mentioned: Cars that received the NOx-reduction update of early 2024
Symptoms: After a visit to the dealer, flat spots when accelerating and judder at steady speeds; sometimes higher diesel consumption. On the Mégane IV and Kadjar the engine may start and then stall.
Possible cause described: In early 2024 Renault and Dacia updated these engines to cut nitrogen oxides (NOx) further. According to an internal Renault technical note from June 2024, updated in February 2025 and reported by L'argus, the flat spots and judder are mainly due to the new strategy widening the periods when the NOx trap is cleaned (regenerated); to do so the engine injects more diesel, which also explains the higher consumption.
Check for the garage: Ask a Renault or Dacia dealer for the new injection ECU reprogramming for these symptoms (Dacia has offered it since May 2024 and Renault since January 2025). It is not a recall with a letter: you have to ask for it. First have them rule out other causes (particulate filter, boost pressure sensor).
Cost cited in the source: No verified estimate: the note does not say whether the reprogramming is free; ask the dealer.A rough figure from the original database, not an up-to-date quote.

Applies if: Weak points of this model from inspections, breakdown statistics and recalls; anything specific to one engine is stated in the sheet.

1.2 TCe chain, EDC gearbox and campaigns on the Mégane IVKnown weak points

Engine / equipment: Renault Mégane IV (petrol, diesel and E-Tech)
Period mentioned: 2016–2023
Symptoms: Chain noise on start-up on the 1.2 TCe (H5F); an EDC gearbox that overheats or jerks when pulling away (especially GT TCe 205); drop links; at the roadworthiness test, suspension and lights.
Possible cause described: The guide rates the 1.3 TCe as reliable. Recalls: GT clutch (1/11/2015–23/1/2017), particles in the oil-pressure valve of the R.S. M5P (1/12/2017–6/5/2019), R9N fuel line (8/11/2018–20/6/2019), curtain airbags and child lock (2016).
Check for the garage: Check the campaigns by VIN; change the EDC oil every 50,000–60,000 km; listen to the 1.2 TCe chain.
Cost cited in the source: No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.

Clogged particulate filter on the 1.5 dCiExhaust and emissions

Engine / equipment: 1.5 dCi (K9K) with particulate filter
Period mentioned: 2010 onwards
Symptoms: Particulate-filter or emissions warning, limp mode with loss of power and frequent regenerations.
Possible cause described: The filter clogs, especially on cars that mostly make short town trips and never complete a regeneration.
Check for the garage: Read the soot load with a diagnostic tool, run a forced regeneration at the garage and check the differential-pressure sensors and EGR. Make long road trips now and then.
Cost cited in the source: No verified estimate; from a regeneration to replacing the filter.A rough figure from the original database, not an up-to-date quote.