P242F: DPF restriction from ash accumulation — the filter that cannot be saved
Soot burns away during regeneration. Ash does not. This code is the point at which no amount of driving or forced regeneration will help.
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Blog
P2452 and P2453: DPF differential pressure sensor circuit
The whole DPF strategy rests on one pressure measurement. When that sensor is wrong, the ECU either regenerates constantly or never regenerates at all.
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P2459: DPF regeneration frequency — the code that says you drive wrong
Not a component failure. The ECU has noticed the filter is regenerating far more often than it should, and that is usually about journeys rather than parts.
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P3400: cylinder deactivation system and the lifters that fail
Shutting off half the cylinders saves fuel and adds a mechanism that fails in a specific, expensive way. Oil condition is what decides which you get.
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Peugeot 208 and 2008: PureTech wet belt and what else to check
One question determines whether a used PureTech is a good buy. Everything else on the list is ordinary by comparison.
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Peugeot 3008 and 5008: larger PSA cars and their diagnostics
The same engines as the smaller cars in a heavier body, with more electronics and a hybrid option. The engine questions are identical; the electrical ones are not.
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Rain sensing wipers not reacting: the sensor lives on the glass
The sensor does not see rain. It measures how light reflects inside the windscreen, which explains almost everything about how it fails.
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Real driving emissions: why lab figures never matched your car
The gap between official figures and reality was not a rounding error. RDE testing exists because the old laboratory cycle could be engineered around.
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Renault 1.5 dCi: the engine in half of Europe, and its four weak points
One of the most produced diesel engines ever made, in Renaults, Nissans, Dacias and Mercedes. Four items account for most of what goes wrong.
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Renault Captur and Scenic: the electrical and emissions picture
Shared Renault engines and a reputation for electrical faults that mostly traces back to one thing worth checking before anything else.
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Renault Master and Peugeot Boxer: large van OBD diagnostics
Two large panel vans that between them carry most of Europe. Their fault lists come from the work they do, not from where they were built.
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Revs hang between shifts: emissions calibration, not a fault
Lift off to change gear and the revs stay up for a moment before falling. Almost every modern manual does it, and the reason is not what most people assume.
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