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Dpf regen circuit location?

16K views 38 replies 6 participants last post by  Shaky 
#1 ·
Hello all,
My first post. I own an Astra J 2.0cdti elite. I'm thinking about a K in the future, either a 1.6d or a 1.4t petrol. I retro fitted a regen dpf light to my J, which is linked to the rear window demister circuit. Could anyone tell me if the Astra K's regen circuit is also linked to the rear heater demister? As if I were to buy another diesel I'd like to fit a retro regen light.
Many thanks.
 
#3 ·
cornishtaz said:
I think it is linked to the rear demister this is on my investigation to do list

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Are you certain? Have you noticed any steam coming from your window demister when it's doing a regen? I'm thinking about a diesel again due to the increased depreciation of used diesels and the improved mpg, compared to the 1.4t. I also drive an auto, which does not help with fuel consumption.
I prefer knowing exactly when it's having a regen, taking the guess work out of it. Certainly made life easier with my current J.
Thanks for the info.
 
#4 ·
Boroboy said:
cornishtaz said:
I think it is linked to the rear demister this is on my investigation to do list

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Are you certain? Have you noticed any steam coming from your window demister when it's doing a regen? I'm thinking about a diesel again due to the increased depreciation of used diesels and the improved mpg, compared to the 1.4t. I also drive an auto, which does not help with fuel consumption.
I prefer knowing exactly when it's having a regen, taking the guess work out of it. Certainly made life easier with my current J.
Thanks for the info.
When mine is doing a regen I've noticed the following

1 Exhaust note is a bit deeper
2 Instantaneous mpg drops by 50%
3 The rear screen has cleared itself without being turned on.

I'm going to wire up a temporary led this weekend to see if it lights when the 3 conditions above are met

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#5 ·
cornishtaz said:
Boroboy said:
cornishtaz said:
I think it is linked to the rear demister this is on my investigation to do list

Sent from my SM-G930F using Tapatalk
Are you certain? Have you noticed any steam coming from your window demister when it's doing a regen? I'm thinking about a diesel again due to the increased depreciation of used diesels and the improved mpg, compared to the 1.4t. I also drive an auto, which does not help with fuel consumption.
I prefer knowing exactly when it's having a regen, taking the guess work out of it. Certainly made life easier with my current J.
Thanks for the info.
When mine is doing a regen I've noticed the following

1 Exhaust note is a bit deeper
2 Instantaneous mpg drops by 50%
3 The rear screen has cleared itself without being turned on.

I'm going to wire up a temporary led this weekend to see if it lights when the 3 conditions above are met

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Yep good news sounds like it does run through the demister circuit. Other symptoms seem similar to my J's regen. I had a dpf light fitted to my J, the auto elec took a feed from a wire under the inside sill area of the passengers side front. After tracing it from the rear demister circuit from the window. I had the light fitted to the dash part of my car. My car regens around once every 3 weeks now, very rarely do I pull the key out of the ignition whilst it's in a regen. One of the reasons I'd also fit one to a K if I were to buy one. Not sure whether I want to take a chance with the 1.4t petrol direct injection engine, considering the ongoing issues.
I've owned vaux's from the 80s.
 
#7 ·
Great, I'll keep my eye out. If it's not too difficult I may have a go myself if I buy a K.
What sort of mpg are you averaging? I've averaged 44mpg over the last 20k with my 2.0cdti auto. 30% town, 50% B roads, 20% motorway use.
I've driven a K, liked it, wasn't that impressed with the brakes, as I know they've downsized them to save weight. Not as sharp as my J's.
Cheers.
 
#8 ·
Boroboy said:
Great, I'll keep my eye out. If it's not too difficult I may have a go myself if I buy a K.
What sort of mpg are you averaging? I've averaged 44mpg over the last 20k with my 2.0cdti auto. 30% town, 50% B roads, 20% motorway use.
I've driven a K, liked it, wasn't that impressed with the brakes, as I know they've downsized them to save weight. Not as sharp as my J's.
Cheers.
My car is mapped from 136bhp and 318nm to 160bhp and 362Nm and still get on average 55mpg mainly A roads but I have a heavy right foot. I find the brakes are ok mine have 300mm fronts and 264mm rears.
My previous car was a J VXR.

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#9 ·
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cornishtaz said:
Boroboy said:
Great, I'll keep my eye out. If it's not too difficult I may have a go myself if I buy a K.
What sort of mpg are you averaging? I've averaged 44mpg over the last 20k with my 2.0cdti auto. 30% town, 50% B roads, 20% motorway use.
I've driven a K, liked it, wasn't that impressed with the brakes, as I know they've downsized them to save weight. Not as sharp as my J's.
Cheers.
My car is mapped from 136bhp and 318nm to 160bhp and 362Nm and still get on average 55mpg mainly A roads but I have a heavy right foot. I find the brakes are ok mine have 300mm fronts and 264mm rears.
My previous car was a J VXR.

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Thanks for info.
I'd be happy with 50mpg, I'd keep my standard (136). Anything over that would be a bonus. I'm not really heavy footed, just on occasion. Thinking about an Sri nav at the moment, I have previously driven one in the past. A lot quieter than my current 2.0cdti tractor. Smoother too, not quite as much grunt. Although I'm not that bothered about that. Would be dropping from an elite spec, really like my current seats, very comfy.
Used diesels for obvious reasons seem to be selling for a bit less or the same as petrols now, which I'm happy about. Even though they cost a little more from new.
I'd also shove a set of all season tyres on it by the end of this year, as I'm running with two sets at the mo.
What's the oil filter housing like to get to on yours? Bit of a pig with the 2.0cdti. Hoping the K is a little easier.
I'll definitely be fitting a retro regen light to it.
Here's a pic of mine fitted to my J. The led warning light cost me around a fiver. My regens take around 7-10mins to complete, around once every 3 weeks now.
Vehicle Car Fixture Automotive design Steering part
 

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#10 ·
This is all very interesting.

What I don't understand though is why is the regen circuit linked to the rear heated window?

Is it on the same relay or something? - but that can't work as it would regen every time you switch the heated window on....

Confused .....
 
#11 ·
The rear screen demister is controlled by the bcm it gets 2 input signals 1 from the switch and 1 from engine ecu when a regen is required either one of these signals will turn the rear demister on. The reason for this is it puts an extra load on the engine and this extra load requires more fuel

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#13 ·
Crunchynut said:
Thanks for the reply, but still doesn't explain why switching on the rear window demister is necessary?

If there is extra load on th engine then why add to it by switching on the demister too?
You don't need to switch on the rear demister via the dash, the regen circuit is linked to it though. Neither would it go into a regen when I press the dash demister button.
When the car goes into a regen my retro fitted light comes on, but not the rear demister dash light, the heated rear screen also comes on. Although when I put the demister dash light on my dpf light also illuminates too. This is an easy retro fit to the Insignia, via a feed from the drivers side door mirror, as the heated door mirror also comes on at the same time (plenty on youtube). I used an auto electrician, he traced the wires from the heated rear windscreen, took a feed from the wires from the lower inside sill area of the passengers side front. That's all I can really tell you. He did the job quite quickly, around half an hour. Although he new exactly what he was doing, charged me around £40, came to my house. I'm sure he could do the same with the K.
If your rear window demister element heats up when your cars having a regen, without your demister dash light coming on, then you'll be able to fit a light.
I just pressed my dash demister button to show the light, it was not during a regen. Although this light does illuminate during a regen.
One of the reasons I used a trusted auto electrician lol.
I've not found any info yet on anyone fitting one to a K, reason I came onto this forum.
Hope this helps.
 
#15 ·
When I do buy an Astra K, it'll definitely be a diesel or the 1.4t petrol. If I do buy a diesel, I'll fit a dpf light & post some pics. Although you might beat me to it. I'm waiting to get the winter over first, as I'm running with a winter set off wheels, which I'll swap over with my J in a few weeks to my summer set. I'd buy all season tyres for a K with the 45's fitted for next winter. Seems to be a better choice of all season tyres now.
 
#17 ·
cornishtaz said:
I can definetly say that when a dpf regen is in progress the rear heated screen comes on. My temporary led has proved this on 4 occasions now.

Only issue now is where to install a permanent led that won't look out of place.

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I'd say that if you can, you want it as high as reasonably possible. I can guess my regen now within around 3 days with my J. Although having the light helps a lot. As I tend now not to pull the key out whilst it's in the middle of one now. Do you know which fuse the rear demister is hooked up too? Where's the fuse board on the K? When I eventually buy a K, think it'll be the SRI spec. So will have some rear reversing sensors fitted by my auto elec, whilst he's on I'll get him to fit the led dpf light. Hopefully somewhere above the gearstick area on the dash. As you've said not wanting it to look out of place. Somewhere easy to access from behind to fit the light too.
Cheers.
 
#18 ·
Boroboy said:
cornishtaz said:
I can definetly say that when a dpf regen is in progress the rear heated screen comes on. My temporary led has proved this on 4 occasions now.

Only issue now is where to install a permanent led that won't look out of place.

Sent from my SM-G930F using Tapatalk
I'd say that if you can, you want it as high as reasonably possible. I can guess my regen now within around 3 days with my J. Although having the light helps a lot. As I tend now not to pull the key out whilst it's in the middle of one now. Do you know which fuse the rear demister is hooked up too? Where's the fuse board on the K? When I eventually buy a K, think it'll be the SRI spec. So will have some rear reversing sensors fitted by my auto elec, whilst he's on I'll get him to fit the led dpf light. Hopefully somewhere above the gearstick area on the dash. As you've said not wanting it to look out of place. Somewhere easy to access from behind to fit the light too.
Cheers.
The fuse box is behind a cover just under the heater controls. You can't tap into the rear demister fuse for the regen led as it is switched ignition live.

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#19 ·
cornishtaz said:
Boroboy said:
cornishtaz said:
I can definetly say that when a dpf regen is in progress the rear heated screen comes on. My temporary led has proved this on 4 occasions now.

Only issue now is where to install a permanent led that won't look out of place.

Sent from my SM-G930F using Tapatalk
I'd say that if you can, you want it as high as reasonably possible. I can guess my regen now within around 3 days with my J. Although having the light helps a lot. As I tend now not to pull the key out whilst it's in the middle of one now. Do you know which fuse the rear demister is hooked up too? Where's the fuse board on the K? When I eventually buy a K, think it'll be the SRI spec. So will have some rear reversing sensors fitted by my auto elec, whilst he's on I'll get him to fit the led dpf light. Hopefully somewhere above the gearstick area on the dash. As you've said not wanting it to look out of place. Somewhere easy to access from behind to fit the light too.
Cheers.
The fuse box is behind a cover just under the heater controls. You can't tap into the rear demister fuse for the regen led as it is switched ignition live.

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I've just put a deposit down for a 2016 Astra 1.6d Sri nav auto. I'm picking it up towards the end of the month. Next job to do, reverse parking sensors and a retro dpf light. I'll post info, once I've had the dpf light fitted. Prob April sometime.
 
#20 ·
Boroboy said:
cornishtaz said:
Boroboy said:
I'd say that if you can, you want it as high as reasonably possible. I can guess my regen now within around 3 days with my J. Although having the light helps a lot. As I tend now not to pull the key out whilst it's in the middle of one now. Do you know which fuse the rear demister is hooked up too? Where's the fuse board on the K? When I eventually buy a K, think it'll be the SRI spec. So will have some rear reversing sensors fitted by my auto elec, whilst he's on I'll get him to fit the led dpf light. Hopefully somewhere above the gearstick area on the dash. As you've said not wanting it to look out of place. Somewhere easy to access from behind to fit the light too.
Cheers.
The fuse box is behind a cover just under the heater controls. You can't tap into the rear demister fuse for the regen led as it is switched ignition live.

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I've just put a deposit down for a 2016 Astra 1.6d Sri nav auto. I'm picking it up towards the end of the month. Next job to do, reverse parking sensors and a retro dpf light. I'll post info, once I've had the dpf light fitted. Prob April sometime.
Cool. It's just the positioning as you need it somewhere in view but too annoying when youve rear demsiter on

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#21 ·
cornishtaz said:
Boroboy said:
cornishtaz said:
The fuse box is behind a cover just under the heater controls. You can't tap into the rear demister fuse for the regen led as it is switched ignition live.

Sent from my SM-G930F using Tapatalk
I've just put a deposit down for a 2016 Astra 1.6d Sri nav auto. I'm picking it up towards the end of the month. Next job to do, reverse parking sensors and a retro dpf light. I'll post info, once I've had the dpf light fitted. Prob April sometime.
Cool. It's just the positioning as you need it somewhere in view but too annoying when youve rear demsiter on

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Suppose light location would be down to personal choice & accessibility. I'm going to have a trusted auto electrician fit mine, along with the rear parking sensors. When he does, I'll post some pics & try to take some photos of the wires he takes a feed from. I could do with the light in a slightly higher position than on my J. Would be easier to notice then.
How frequently does yours go into a regen? Mine is around once every 3 weeks with my 2.0cdti, I cover around 10-12k a year.
The brakes on the K I've just put a deposit down on were far better than the previous K I drove (both same spec). All I can think was the pads & discs must have been getting down a bit on the first one I took a test drive with. Didn't have to push my foot down as far to feel their biting point.
Road tyre noise seemed slightly louder with the K, prob down to the tyres being 45's, J is on 50's. Although the overall driving experience was good. Looking forward to picking it up :)
 
#22 ·
cornishtaz said:
Boroboy said:
cornishtaz said:
The fuse box is behind a cover just under the heater controls. You can't tap into the rear demister fuse for the regen led as it is switched ignition live.

Sent from my SM-G930F using Tapatalk
I've just put a deposit down for a 2016 Astra 1.6d Sri nav auto. I'm picking it up towards the end of the month. Next job to do, reverse parking sensors and a retro dpf light. I'll post info, once I've had the dpf light fitted. Prob April sometime.
Cool. It's just the positioning as you need it somewhere in view but too annoying when youve rear demsiter on

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What about this for an area to put the dpf light? Betwen the two dials I was thonking. I've just picked up my new motor. Will have one fitted. Just making sure all is good with it until I do. Although didn't realise it does not have a cd player lol. Old school I am. I shall have to embrace new technology :lol:
 

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#24 ·
I'm not sure whether you have to replace this button modules a few at a time? I once replaced the sports button module on an Astra H & prog it in myself using Opcom. That came in a complete unit/module Inc the hazard warning light. I'll have to ask the auto electrician when he has a look. I'll post some pics when I get it sorted. Probably best to have it somewhere you'll notice it. It was a bit low down on my previous J.
I'm very impressed with my K. A big step up from my previous J. The 1.6d is the quietest diesel I've driven and the auto box is very smooth.
 
#25 ·
I've just retro fitted my dpf led warning light. I'd like to give a big thanks to "cornishtaz", for letting me know the location of the demister live feed wire.
The picture with the screwdriver near a wire, is the one you need to take a feed from (purple/brown). The other is where I took an earth feed from for the led light. The wiring loom I took a feed from is within the passengers foot well. To the left hand side. I also took off the plastic sill cover to gain an easier access. Then fed the wires around the glove box area into the gearstick console area.
This is for the auto model. In principle the same, apart from the gear knob surround will be different. Just a case of finding wherever you want to place the light.
 

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