- As soon as the petrol engine kicks in do you get a message engine must run longer?
The last point is interesting as basically my last car and new one both suffer with this message along with and E and a slash through it. The new car has started not to allow me to switch back to electric even after several miles of driving like the last one did, however the three weeks before worked perfect.
Any Cupra mechanics out there shed some light on this things?
Thanks
Mark
The last thing I’d ever describe myself as would be a Cupra mechanic!
. Firstly, apologies for the long post, but here goes for my ‘armchair diagnosis‘ (a.k.a. forum member opinion) of the reason for the ‘engine must run longer’ message. I think it might be linked to the petrol / gasoline particulate filter (GPF / OPF) and the filter regeneration process; AFAIK, VAG hybrid cars are equipped with a GPF / OPF in the same way that VAG ICE cars are.
Setting aside for a moment the fact that your car is a hybrid, for cars equipped with a GPF / OPF the particulate filter collects harmful particulate matter from the combustion process from the ICE, and when the particulate matter reaches a certain level it is neutralised through a regeneration process. Regeneration can be either passive or active, depending on types of journey driven and how the vehicle is used;
- If the majority of journeys are long(er) with the ICE operating at its optimum running temperature. Under these ‘normal’ (for an ICE) driving conditions, the very high exhaust temperatures reached are high enough to passively neutralise the accumulated particulate matter in the OPF / GPF.
- If a high proportion of shorter journeys are driven where the ICE doesn’t reach its optimum operating temperature. The car will initiate an active / forced OPF / GPF regeneration process and the active / forced regeneration process uses additional fuel to increase exhaust temperatures to neutralise accumulated particulate matter. Owners of ICE cars often notice a marked worsening in fuel consumption during an active / forced regeneration because of the additional fuel used. The car’s ICE needs to be kept running during the regeneration process for it to be fully completed.
With a hybrid, depending on journey types and duration driven, the ICE may normally only be running for short periods of time and not reaching the optimum operating temperature for much of that time. Under these conditions, it’s likely that most OPF / GPF regenerations will be active / forced rather than passive. When the message ‘engine must run longer’ is displayed, it’s likely an active / forced regeneration is taking place and the message is a prompt not to turn off the engine so the regeneration process can be allowed to finish. An ‘in progress’ regeneration would also explain why your car won’t allow you to switch back to electric mode.
With ICE cars, if the regen process is interrupted, it will recommence at the next - and subsequent - ignition cycle(s) until it is completed. I suspect the same may apply to a hybrid car too.
When I owned my OPF / GPF equipped (non-hybrid) petrol engined VW, there were some tell tale signs when an active OPF / GPF was happening (some or all of the above tell tale signs might not be relevant to a hybrid car);
- deeper exhaust note
- slight hesitancy in acceleration
- slight ‘lumpiness’ in engine idle
- significant increase in fuel consumption
- stop start function was inactive
- engine fan running continuously
It‘s purely speculation on my part that the above is the reason for the ‘engine must run longer’ message in your hybrid; if it is [the reason], then hopefully the above is useful / relevant. All of the above also assumes your car is equipped with a GPF / OPF.
