Author Topic: Scbs forward malfunction and car goes into limp mode  (Read 505 times)

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Offline lynnesafc

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  • Year: 2015
Scbs forward malfunction and car goes into limp mode
« on: March 08, 2020, 09:12:03 am »
Hi guys,

I currently have the mazda 6 2015 sport nav tourer, im currently experiencing the scbs forward malfunctuon display on my dash, the car then goes into limp mode. I was advised to wash my window and clear the sensors, which wasnt dirty but i cleaned it anyway. It made no difference and 2 hours later half way down the M6 the light came on again. If i park the car up for 10 mins it clears it but it comes back on again after about 20/30 miles. Then as the car is in limp mode the DPF light comes on telling me the soot level is too high, as i cant accelerate i cant force a regen. Now somebody has also advised me there is a laser somewhere in the front bumper, does anybody know where this is located so i can see if that needs cleaned??? I know there has been some subjects on this matter but i cant locate it within the group.
Many thanks Lynne ;)

Offline apav

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Re: Scbs forward malfunction and car goes into limp mode
« Reply #1 on: March 08, 2020, 11:41:10 am »
https://www.mazda.com/en/innovation/technology/safety/precrash_safety/sbs/

I did not go through all the information but it says:

"a laser sensor mounted on the windsheild senses the car in front"

Have you ever replaced with windscreen?

https://owners-manual.mazda.com/gen/en/mazda6/mazda6_8gk3ee18c/contents/05200100.html

There is a parking sensor system in the bumper but I do not think it is linked to the other system.

The limp mode is strange.

You get an auto brake warning. You then go into limp mode. You then get a DPF regeneration warning.

I think you have to investigate based on the order the errors happens.

The DPF is the last on the list and so it can be a byproduct of the other faults.

Offline lynnesafc

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  • Colour: Soul Red Metallic (41V)
  • Engine: 2.2L
  • Fuel: Diesel
  • Transmission: Manual
  • Trim: Sport Nav
  • Year: 2015
Re: Scbs forward malfunction and car goes into limp mode
« Reply #2 on: March 09, 2020, 12:56:50 pm »
No i havent had windscreen replaced, ive had it in the garage this morning on the computer and there are no fault codes logged. I havent had any other lights on the dash just the traction control one appears when the SCBS forward malfunction appears, then obviously it cant regen as its in limp mode, no DPF light appears just another warning telling me the soot accumulation is too high, but as sokn as i turn the engine off it disappears. Im at a loss now as to what is causing it

Offline apav

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  • Engine: 2.0L
  • Fuel: Diesel
  • Transmission: Manual
  • Trim: TS2
  • Year: 2009
Re: Scbs forward malfunction and car goes into limp mode
« Reply #3 on: March 09, 2020, 02:41:26 pm »
You have too many problems.

I am not sure how the traction control gets involved.

Are you sure your battery is fine?

The DPF should regenerate as long as the car moves faster than X speed on Y gear. For the second generation 2.0 engine this is as low 25mph on 3rd gear. Even if you are in traffic and do not move the regeneration keeps happening but takes longer to complete.

When you turn off the engine without the regeneration being completed, the regeneration will start as soon as you restart the engine. You will need to do some driving before it starts.

Read some more posts about the auto braking. It is not an easy to resolve issue. Somebody had the sensors readjusted.

You have scbs, traction control, DPF, soot warnings. If Mazda cannot read any faults, did they ever wonder it is something like the battery causing all these problems? If you went to a generic garage, some of their machines do not read all cars. So you may be unlucky with them.