Honda CR-V 2.2 i-DTEC: the timing chain that wasn't.

What came in

A 2011 Honda CR-V with the 2.2 i-DTEC diesel, at about 120,000 miles. The driver had noticed a vibration. The owner suspected the cam chain, stretched past the limit of its adjuster and upsetting the timing, and asked whether we would replace the chain and its running gear. The engine management light had not come on.

Our first answer, before we had seen the car, was that it needed a diagnosis before anyone quoted for a chain. A vibration like that can be the chain and guides. It can also be a failing dual-mass flywheel, an injector or the engine mounts.

What we found

The car came in on 14 September 2026 and went through a diagnostic check.

We could not reproduce any of the reported symptoms. There was no rattle on a cold or a hot start. There was no rough running, and no knocking, tapping or other unusual engine noise. Nothing in the fault memory pointed at timing or camshaft correlation.

That matters, because a stretched chain usually leaves evidence: a rattle at start-up, a correlation fault logged by the engine control unit, or both. This car had neither.

There was one stored fault, on the mass air flow (MAF) sensor.

Why a MAF fault matters on a diesel

The MAF measures the mass of air going into the engine. The engine control unit uses that reading to decide how much fuel to inject and how far to open the EGR valve.

A MAF that is going off rarely fails outright. It drifts and reads slightly wrong, so the engine control unit fuels to a false number. On a diesel that usually means over-fuelling. The signs are:

• a puff of smoke under acceleration
• a flat spot or hesitation
• occasional lumpy running
• sometimes a shudder under load, which a driver could fairly call a vibration

It also tends to come and go. That fits a driver noticing it on the road and us not seeing it on the day.

The knock-on effects are the real reason to fix it:

• The DPF fills faster. Extra unburnt fuel means extra soot, so the diesel particulate filter loads up quicker and the car runs regenerations more often than it should. Frequent or interrupted regenerations are how these cars end up with a blocked DPF.
• The engine oil gets thinned. Repeated post-injection during regeneration dilutes the oil over time.
• The EGR side cokes up. The same wrong airflow figure upsets EGR metering, which cokes up the EGR valve and the inlet over the longer term.

None of it was urgent on the day. Replacing a sensor now costs a great deal less than dealing with a DPF later.

What we did

We recommended replacing the MAF sensor. The plan was to fit it, clear the fault memory and road test the car. While it was with us we would also read the DPF soot load and regeneration history and check the EGR on live data, to see whether the sensor had already caused anything else.

The owner had a choice between a genuine Honda sensor and an aftermarket one, and went with the aftermarket part. It arrived on 17 September, and the car came back in for it on 24 September. The owner asked us to keep the old Honda sensor for them, to try cleaning it.

What to watch for on a 2.2 i-DTEC

• Listen in the first second or two of a cold start, especially after the car has stood overnight. That is when a worn chain rattles.
• Look after the oil. Chain wear on this engine is closely tied to oil condition. Keeping to the service interval with the correct grade is the best thing you can do for the chain.
• Don't assume a vibration is the chain. Smoke under acceleration, a flat spot, lumpy running or a shudder under load can all be fuelling. Get the fault memory read before anything is ordered.
• Take frequent regenerations seriously. If the car seems to run DPF regenerations more often than it used to, find out why before the filter blocks.

If your diesel has a symptom you can't pin down, start with our diagnostics service. Honda owners can also see our Honda specialist page.