My 2013 Citroën DS5 Hybrid4 is very (and maybe increasingly) reluctant to downshift when applying little to moderate throttle in higher gears and at low revs. The car - being the hybrid - have the MCP 'Piloted Manual Gearbox' which works in co-operation with the electical drive train.
Now if I start from zero and accelerate up through the gears with little or moderate throttle everything feels good and final shift from 5th to 6th will typically take place at 80-90 km/h (corresponding 50-55 mph). This feels normal and I will not experience 'rough sound' or vibration from the engine just after any upshift. - So thats perfect.
However if I come fully off the throttle on straight and level road the car will stay in 6th gear some times all the way down to 65 km/h (40 mph). - Which is in fact still feels okay as long as the throttle is off. However if I then start to apply throttle slowly the the gearbox will not shift down, the engine will run really rough and will be vibrating badly. - Only way to force the downshift will be to 'slam' the pedal significantly or to use the paddle shifter manually.
This behavior is also present at the 4th to 5th shiftings (at lower speeds of course) but not so much in lower gears. This problem is especially felt when running at undulating road on cruise control set to 80 km/t (50 mph). 6th gear fine as long the road is flat, but when a hill begins - and the cruise control applies throttle - the engine starts to run rough and the climb must very steep before a downshift is performed automatically.
Running i 4WD or Sport mode improves the whole situation a bit but not significantly. Diagbox presents no faults from engine-, gearbox- or Hybrid CPU's.
Sorry for the long explanation here. But I would like to hear how other Hybrid4 owners experience this. It doesn't feel healthy for the engine, so I hope it's not normal behaviour?
I've read the gearbox CPU - amongst a lot other - reacts on road slope, and I suspect maybe a sensor problem. However I haven't been able to figure where this (or these) sensors are placed. Neither how to access through Diagbox. Does anyone know? ....Any help or input much appreciated...
PS: Initialising gearbox clutch bite point and engine torque transmissibility performed recently, but no changes regarding this...
BR /tka
Thomas Kjaer-Andersen, Denmark
