An indicator you can add to know when a DPF regen is happening...

[Sol]

I found a guide on C4 owners.org, regarding an indication LED to show when a regen is taking place. Now since the B9 is really a C4GP under the skin, then this may also work and is totally testable, or removable if it doesn't work. 

You need a 12v led with wires already on it preferably, from eBay or similar. 

When the car does a regen, apparently it switches on the heated mirrors, but does not light the indicator inside, on the heated screen / mirror button. So, you can add an LED to the heating connector behind the mirror glass and if it comes on when you don't have the mirror heating on, the ECU is doing a regen.

Details attached in a pdf. Well worth a try.

Obviously you need the heated mirrors option already enabled I guess but it may work as long as the brown wires are there, inside the mirror housing. You can test the LED polarity by switching the mirror heating on and making sure the LED comes on manually.

No idea why the car does this, but very handy.

[RobS]

When doing a regen the ecu puts on several high amp consumers to load the alternator, especially needed if you are driving slow in town. Regen will fail if engine is not doing enough and have to start again later. If regen fails several times that is when you get real problems and end up having to get a forced regen at a dealers or an off the car cleanout.

[Sol]

But how will you know the regen is happening.....hence my previous post.

If you drop below 60 mph, the regen will stop. It doesn't do a regen at town speeds.

[RobS]

I have a Vauxhall with a DPF and they will try to regen at town speed if it gets really badly full and you are not doing any high speed driving. There is no indicator for a normal high speed regen apart from smelling hot. When doing one of the low speed job there is a dash indicator and the heated rear window is on as well. The owners manual tells you to drive in a low gear keeping the revs over 2000 and keep driving until the regen light goes out.

[Gryffindor]

When doing a regen the ecu puts on several high amp consumers to load the alternator, especially needed if you are driving slow in town. Regen will fail if engine is not doing enough and have to start again later. If regen fails several times that is when you get real problems and end up having to get a forced regen at a dealers or an off the car cleanout.

What a great bit of knowhow - thanks. Explains why my Volvo truck has to go through several cycles even though each one ends with a 'regen completed' message. It always seems to want to regen in town when at low or zero road speeds as well.

[Gryffindor]

the B9 is really a C4GP under the skin...

Really?

Sorry for veering OT but I have to ask - I know you're speaking of the mechs and elecs, but would the front seats be cross-compatible in terms of rails/fixing?

[Sol]

Could be mate, I know the two vehicles are identical under the skin, brakes, shocks, suspension, all parts are interchangeable. The body shell is different looking and the interior may be too. But the mounts should be the same as the floorpan should be exactly the same.

[Gryffindor]

Floorpan - of course. Much thanks!

Reminds me of when some bod at Vauxhall had a brainwave when tasked with solving a massive overstock of Astra floorpans - he invented the Zafira.