Auto stop feature - the "A"symbol is flashing amber

[Jeff B]

I have searched the forum and have seen other issues with this auto stop feature like "why does it only work occasionally" but I have not found anyone with my specific issue. The auto stop feature is one I never use because I think it is a drain on the battery and the starter motor, so I automatically press the A button on the centre console everytime I start the engine. Recently the amber "A" sign has started flashing as soon as I start the engine. I have had the battery checked and it is working 100%. The handbook tells me there is a fault and to contact my Honda dealer.

I have done this and "computer say": fault is with the brake booster sensor. This makes no sense to me and to replace this will apparently cost £300 plus labour! I have tried switching on the ignition for a few seconds before actually starting the engine but no joy. Very occasionally the warning lamp does not flash and is steady as you would expect, but probably only about once in ten attempts! I can't help wondering if there is simply a loose connection but as I have no idea where the brake booster sensor is I am a bit stumped.

I just wonder if anyone else has come across this issue and what they did about it?

Thanks for any ideas!

P.S. My car is a 67 plate Jazz 1.3 SE I-VTEC CVT.

Later note: I should add that in a way this fault is a blessing as the auto stop will not work! The dealer assures me that it is safe to driveso there is no rush to get it fixed. I am concerned though what would happen when I take the car for its M.O.T. I'm not too confident that the test chap will simply ignore a flashing light on the dashboard, especially one that covers the entire right hand screen!

[UKjim]

I’m sorry I can’t answer your question but I can confirm that any warning light displayed or flashing on the dashboard will result in an MOT failure.

[HertsHonda]

@Jeff B
Could the problem be that pressing the "A" switch on every journey has caused a fault at the switch?
For 2 years I have ignored the A (crossed-out) with a battery sign next to it in the multi-information display (MID).
Also, have you tried 'configuring' the AIS via the MID?

[ColinB]

It's not very clear why a fault with the braking system should flag up as a fault with the AIS, but I guess it's possible because everything is interconnected via the car's computers. If you don't believe the diagnosis, try another garage for a second opinion. But if it's genuinely an issue with the brake booster sensor, then you should certainly get that dealt with because it can affect the car's brakes.

[Jeff B]

I’m sorry I can’t answer your question but I can confirm that any warning light displayed or flashing on the dashboard will result in an MOT failure.

OK, thanks for that. Sadly it's what I feared!!

[Jeff B]

@Jeff B
Could the problem be that pressing the "A" switch on every journey has caused a fault at the switch?
For 2 years I have ignored the A (crossed-out) with a battery sign next to it in the multi-information display (MID).
Also, have you tried 'configuring' the AIS via the MID?

No I haven't tried reconfiguring as I didn't know I could do that! No one at the dealership mentioned that. I'll check the user manual. I can get rid of the large flashing "A" symbol on the info display by pulling the info button up briefly but not the smaller icon on the left hand dial - that is permanently flashing.

Don't know if the switch is the issue. A question to ask if I go for a second opinion.

Thanks for the info.

[Jeff B]

It's not very clear why a fault with the braking system should flag up as a fault with the AIS, but I guess it's possible because everything is interconnected via the car's computers. If you don't believe the diagnosis, try another garage for a second opinion. But if it's genuinely an issue with the brake booster sensor, then you should certainly get that dealt with because it can affect the car's brakes.

Yes, as I said in my post it didn't really make sense to me. I think getting a second opinion is a good shout. Unfortunately in rural west Wales we aren't too blessed with Honda dealers but we do have some auto-electrics specialists. Could I trust them to give me an accurate diagnosis?

[Lord Voltermore]

I’m sorry I can’t answer your question but I can confirm that any warning light displayed or flashing on the dashboard will result in an MOT failure.

I disagree.  Only those that indicate a  dangerous fault should fail. But not if it only  to alert the driver that non essential or legally required  aids are currently inactive, such as  stop idle, service reminders, or things like parking sensors, lane keeping assist etc  are inactive due to condensation, dirty sensors etc. And probably some other orange lights.  A red light is more likely to be a test failure.
 
Incidentally  a  TPMS warning light should not fail if the tester is satisfied the system is working correctly and  it is indicating a low tyre pressure  . The low tyre pressure itself may not fail either as its not part of the test. 

Problem is  you cant expect testers to know the ins and outs of all warning lights on all cars and you dont really want to have to argue your case or refer to the owners manual.   And if the manual says  "consult dealer" it can cover a multitude of possible causes ,which may justify a cautious test fail.   

An independent garage/auto electrician may be able to read fault codes in broad terms  enough to exclude some possibilities.  But they may not have the knowledge to trace faults  down to a particular faulty component.   

[Jeff B]

I’m sorry I can’t answer your question but I can confirm that any warning light displayed or flashing on the dashboard will result in an MOT failure.

I disagree.  Only those that indicate a  dangerous fault should fail. But not if it only  to alert the driver that non essential or legally required  aids are currently inactive, such as  stop idle, service reminders, or things like parking sensors, lane keeping assist etc  are inactive due to condensation, dirty sensors etc. And probably some other orange lights.  A red light is more likely to be a test failure.
 
Incidentally  a  TPMS warning light should not fail if the tester is satisfied the system is working correctly and  it is indicating a low tyre pressure  . The low tyre pressure itself may not fail either as its not part of the test. 

Problem is  you cant expect testers to know the ins and outs of all warning lights on all cars and you dont really want to have to argue your case or refer to the owners manual.   And if the manual says  "consult dealer" it can cover a multitude of possible causes ,which may justify a cautious test fail.   

An independent garage/auto electrician may be able to read fault codes in broad terms  enough to exclude some possibilities.  But they may not have the knowledge to trace faults  down to a particular faulty component.

Thank you for your reply. I have made an appointment with a local independent auto-electrics guy for later this month so I'll see what he comes up with. Regarding the MOT issue, he said what you said i.e. it should not be a reason to fail the MOT but he suggested that I talk to the guys at the MOT garage beforehand and get their reaction before booking the test. The MOT is not due until August so I am not panicking anyway.

I have searched a lot of second hand car part Internet sites but no-one seems to offer the brake booster sensor that the Honda dealer reckons is the problem. However it looks like I can buy the entire brake servo assembly for about £30 but I need to check that that includes the sensor. Pictures from some suppliers show it and others don't. I can find new sensors alone for other cars and they are of the order of £30 to £50, nowhere near the £300 the Honda dealer quoted!

I still can't understand what the brake booster sensor has to do with the auto-stop/start function!

[Jeff B]

@Jeff B
Could the problem be that pressing the "A" switch on every journey has caused a fault at the switch?
For 2 years I have ignored the A (crossed-out) with a battery sign next to it in the multi-information display (MID).
Also, have you tried 'configuring' the AIS via the MID?

I cannot see any means of configuring the auto stop system from the MID on my Jazz model. I can do several other things but not that. I think if it were possible then wouldn't the Honda garage have done that?

[Jeff B]

Second opinion from the independent autoelectrics chap seems to confirm the initial conclusion that the brake booster sensor could be the source of the fault condition. I have ordered a complete brake servo mechanism from an on-line secondhand parts dealer which includes the sensor. Worth a gamble at £30 I think! (I couldn't find the sensor alone anywhere, apart from the one offered by the Honda dealer at £300).

This should arrive tomorrow and will take it to be fitted and tested later this week by the independent guy. Fingers crossed.

[Jeff B]

Success! The "new" (secondhand) brake booster sensor was fitted and has done the job. I still have the rest of the brake servo plus master cylinder if anyone needs one anytime. I have been able to make out the part number of the sensor which is in the tiniest imaginable font and very faint and it is Denso 079800-9930. Useful to know if ever I get the same problem again. Still can't believe a new one would cost £300 though. Shades of the famous NASA "bolt removal device", aka spanner, which cost $hundreds.

[Toptek]

Do you have a photo of the sensor please as I'm keen to know should this be an issue at some point in the future as the GK starts to develop faults.
Was it easy to replace?