Hi Doctor. 

My brother, who lives in Spain, has had to have a new DPF and ECU on his Toyota Yaris D4-D. It has done some 93,000 kilometres. There was a similar problem around 2,000 kilometres before and the dealer just did a forced DPF clean. But this time he was doing 100kph on the Autovia when the cruise control disengaged and all the warning lights came on. He stopped for five minutes and then continued the final 200 kilometres home alright. He took the car in to the local Toyota main dealer and then returned the next day, expecting a bill, only to be told that it was all under guarantee! Advice from the dealer was every 300 kilometres to drive in 4th gear at 90kph plus for 20 minutes, but not to use the cruise control. Your thoughts on the last part please! 

Unconfirmed report on the web is that the Fiat DoblÚ supplied for the Post Office (UK presumably?) has a switch and warning light to avoid DPF problems with stop/start usage. Presumably they leave the engine ticking over until a DPF clean has finished. No doubt with your contacts you can confirm or dispel this statement. If true, I suppose that for the usual owner it would be a waste of time, as many just seem to drive with warning lights on and have no idea what they mean anyway! Glad you are keeping up the most interesting pages in Diesel Car. 

Bob Fisher

Hi Bob. Interesting. It might throw some more light on things if you could say, or find out what his normal motoring consists of, in terms of short/long runs. Also, what age is the Yaris, such that it was all sorted like that, under warranty. I have a friend with an Auris 2.0 D4-D who has always been staggeringly well treated by his local Toyota dealer ñ he had the best part of a full engine rebuild when it was about four-to-five years old, all free of charge. Good on Toyota!

A DPF regeneration will not continue on tickover though, as there’s not enough heat build-up. The instruction not to use cruise control during an attempted regeneration would be to make it stay in fourth gear, working fairly hard. With cruise control (in fifth gear), the engine speed would be too low for optimum regeneration conditions, due to not enough heat build-up. Best regards,

Doc

Bob then came back, writing:

Sorry about lack of details. The Yaris is only two years old. It does some short trips, but also some very long ones as well. His driving style is gentle, with minimum revs. His complaint, compared to the previous Yaris Verso, is that the 90PS engine is not as flexible as the 70PS engine in his old, lower powered, Yaris Verso. Before he purchased the car, I did mention that he might be better suited to a petrol car! Interestingly, the engine oil has not crept up the dipstick at all, as one might possibly expect from failed attempts at regeneration. 

Bob

Hmmm. I agree. He covers quite a few miles, doesn’t he? Not the sort of motoring that you would expect to give any engine DPF problems. Maybe Toyota does have a DPF problem on this engine, hence the warranty cover? It’s the sort of situation where one might wonder if somebody had been using non-low-ash oil, and it was ash that had bunged up the DPF, hence maybe why the DPF clean did not work. I’m presuming that what the garage did was simply a forced regeneration, which evidently did not work.

No reason for anyone to use the wrong oil ñ it’s quite civilised in Spain, and no reason to use any cheap oil of the wrong specification. On paper, there’s no reason whatsoever for the later 90PS engine to feel less flexible than the earlier lower powered engine though, the reverse in fact, the figures being: Previous Verso: 125lb ft @ 1,800-2,400rpm. Later 90PS Yaris hatchback 151lb ft @ 1,400-2,800rpm. But then the gearing in his current car could be significantly higher.

Could it just be that your brother needs to use the lower gears a bit more?  I think probably so.

Best regards,

Doc

To which Bob replied:

I once drove his previous car ñ it was the “Postman Pat” Verso ñ and accelerating hard to join a motorway he was most unhappy when I exceeded 2,000rpm. ìYou will wear it outî I was told!î

That rather confirms my thoughts!

Doc