Intermittent Parking Sensor Issue

Car: 2012 Accord 2.2 iDTEC EX
Car bought Dec 2015

Note that the dealer I bought the car off have been nothing but helpful. And are continuing to cover the issue under warranty despite the year warranty running out without any queries. I brought thsi issue to them a month or two after buying the car and its now approaching a year and a half.

Problem: Every so often the parking sensors fail in some manner. The dash lights up with all sensors showing as faulty. It can be a month between happennings, or every day for a few days. I can detect no common factor. Apparently there are no codes
Only happens when starting the car. If the problem happens, then switching off the car and switching it back on does NOT cure the issue
Operating the switch has no effect on the problem

Cure - there are two mechaninism's to "cure" the problem.
1. Drive around for a while. After any time between say 10 minutes and a couple of days their is a beep and the sensors start working again. I did notice that when approaching the dealer with the problem lit it tended to fix itself just before arriving there!!!
2. After reaching the giddy heights of say 10mph, break hard (enough to activate the anti-lockl brakes). Almost always about a second after braking there will be a beep and the sensors start working again.

Once the problem is "fixed" it will not go wrong again until the car is switched off and left for a while somewhere

Dealer has changed a couple of sensors - no effect
Dealer has changed the "brain" - no effect
Dealer is now planning on changing the loom - I think they are getting desperate

Any thoughts?

After writing this down I have thought of something - I wonder if anyone will come up with the same idea......

sometimes the sensors just need a good clean

Well I was playing with things yesterday to test my theory.
It is my opinion that the switch on the dashboard is not working reliably - but not in a consistent failure mode. When I spoke to the garage they indicated that they had not checked the loom where it connects to the switch or the switch itself.

Also just as a thought - what on earth is the point ion having a switch that turns off the parking sensors. Why would anyone want to turn them off, ever, unless they were just being stubborn about modern technology to proove they don't need em

Sean

What sort of switch is it i.e. is it like the VSA on/off switch ?

Its a push button switch with a dull led type light on. Due to its apparently intermittent operation I am not sure wether the light means on or off.
Looks similar to:

In the circuit diagram the switch has two lights built in.

One of the lights (dimmer of the two) looks as if it should be on all the time and its brightness can be controlled by the dash-lights brightness control.

The other light (brighter of the two) looks as if it should come on when the parking and back-up controller is enabled (by the switch).

It looks to me as if the switch is a latching switch, which is what I meant by asking if it's like the VSA switch, because the latter is not a latching switch , no audible or physical "click" (on 7th gen at least)

For towing. Gets a little upset when you put it in reverse otherwise.

Goodluckmonkey said:

For towing. Gets a little upset when you put it in reverse otherwise.

Click to expand...

Yes - makes perfect sense. Obvious (once pointed out)

Thanks

Sean

Is it a latching switch ?

that's what I meant by asking if it's like the VSA switch, because the latter is not a latching switch , no audible or physical "click" on the VSA switch (on 7th gen at least)

does the "light" in the switch get brighter or is it always the same brightness ?


edit:
the reason I ask about the type of switch is because if it's a "silent" toggle switch (as 7th gen VSA switch), and if only one light is lit, then going by the circuit diagram, the problem might be due to a faulty light in the switch .....and if that is the cause, "well done Honda" :lol:

The switch seems to operate in an intermittent non predictable manner.

It appears to have a single light that is either lit or not lit indicating whether or not the sensors are turned on. At the point I am not sure which way round is which. I THINK out is sensors on with lit being sensors off

I shall give it a stab or two tomorrow

If there is an "in" and an "out" feel to the switch then it's a mechanical latch, which is not like the VSA switch, the latter is more like the power-on button on a PC (the motherboard on a PC receives a momentary connection across two pins which tells the PSU to power up, the "on" switch does not latch mechanically).

Oops- I forgot
I shall (hopefully) try this evening

Sean

OK - so how is this for sense:
BTW - when I press the switch, it doesn't seem to have an on or off and no latch

Start with working sensors
Press
1 - Beep
2 - Sensors switch off (all around)
3 - no effect
4 - Beep - Sensors work again
5 - Sensors fail
6 - no effect
7 - no effect
8 - no effect
9 - beep - sensors work

Given where I was, and the ambient light I was unable to tell if the light was on or off.

IT does seem to point that the problem is in the switch (or possibly in the loom behind the switch - but that seems less likely)

You're definitely onto something Sean

I've seen a Switch Test/Replacement in the Parking and Back-up Sensor System section of the 8th gen ESM , two bulbs in the switch if the car has headlight washers

I wish it did have headlight washers (but I suspect I would need a new bumper, washers and ***orted other kit to fit them) - might keep my HID's clean

Its under warranty - so Honda will be paying once I persuade them it is likley to be the switch

Regards

Sean

If the car doesn't have headlight washers then I think the switch resembles the 7th gen VSA on/off switch

Well Slough Honda replaced the switch today
Pressing it no longer causes the sensors to intremittently fail and recover
It now operates as I think it ought to -but time will tell

Yeah looking positive