Jump to content

ABS warning light


TJW

Recommended Posts

Good afternoon,

 

Been wondering if anybody can help.

 

Gave the bike (NC700X, 2012) a wash today.

Nothing fancy (no pressure washer, etc.), just hosed it down, sprayed with MucOff, cleaned with sponge and rinsed it off with a hose again.

 

Ever since then the ABS warning light stayed on. Took both sensors off, cleaned them, put them back on ... still on after 6 mph.

Cleaned the rear and front pulser ring  ... still won't go off once I go past 6 mph.

 

Anybody any idea what the problem is?

 

Cheers.

 

Link to post

If it's just water then hopefully it will fix itself in time. The rev counter on my Er6n swung wildy regardless of actual revs for quite a few days after I'd ridden through the worst cloudburst I can remember.

Link to post
Andy m
33 minutes ago, trisaki said:

Try doing  a ecu reset 

Sorry, there is no such thing. Clearing the error memory does nothing but remove potentially useful information.  When the ECU fires up it will just see the same current fault, it's a control loop pure and simple, no hierarchy or stored information, no latched warnings after ignition on. 

 

There is water in the loom or the battery voltage is low. I would put it on a battery charger and blather it in WD40. If that doesn't work, start working your way through the connectors. 

 

Andy

  • Like 6
Link to post

 

15 minutes ago, Andy m said:

There is water in the loom or the battery voltage is low. I would put it on a battery charger and blather it in WD40. If that doesn't work, start working your way through the connectors. 

 

Andy

 

ABS is notoriously sensitive about battery voltage (I assume - but don’t really ‘know’ it’s because it requires a full 12 V to work). My first thought would be to properly test/charge the battery. My second thought would be to be grateful to the warning light for alerting you to a possible problem. Remember that the brakes will work entirely normally but without the fail safe of anti-lock so care should be exercised this weather until it’s sorted.

 

Modern electrical systems are surprisingly robust including ABS ones. As Andy says a connection problem or battery voltage would be my guess.

  • Like 2
Link to post

I can’t see how’s the battery voltage affects any system when the engine is running. The PMA (permanent magnet alternator) feeds all the electronics and charges the battery. The voltage will be higher than the battery’s.

 

The battery acts as a DC filter (like a big capacitor) and smooths the output of the R/R (Regulator / Rectifier). As the battery degrades with usage and time that property also fades... But I don’t believe that the ABS unit is so sensitive to DC quality.

 

The battery also acts as a buffer. It may feed the electronics when the PMA can’t produce enough power. When braking a weak battery I suppose  it can be a reason for an ABS to fail but this is not the case when just testing its operation.

 

Most probably some humidity in a connector causes  the problem. What Andy said...

 

Andy may enlighten us with more details about its power requirements...

  • Like 1
Link to post
Andy m

ABS is voltage sensitive because the inductive analogue wheel sensor signals are chopped into a square wave then added back on their own sine wave to produce a rate of change measurement for the angular decel via the crossing point without a clock. If the square wave is doing ones and zeros and then a 0.7 pops up because it doesn't reach the crossing point and is logged as an unexpected zero, the computer says no. This is effectively 1940's analogue electronics in logic terms, just a control loop, because no one can afford to reapprove the real basics. They use modern chips but still acting like a set of thermonic valves or basic transistors or even a mechanical flywheel and clutch.

 

Once it leaves the loop "are we slipping? -Yes-fire valve-are we slipping? ..." and enters the fault loop it's stuck there until the ignition is keyed. Once the ignition is keyed it just goes back to box 1 "Is connection 1 open circuit?.. Is connection 2..."

 

The trouble with the bike warning light sequence is that you can't tell if it was bad at ignition on, dropped during cranking or simply doesn't like the signals as it passes 5 kph. 

 

Andy

  • Like 2
  • Thanks 1
Link to post

Thanks guys ...

It can't be the voltage/battery as put a brand-spanking new one in just a week ago (cold weather of previous weeks killed the old one). Also, as said, it worked perfectly one moment and then not so perfectly the moment after the wash. Don't think that was a coincidence ... so will go with the water in the connector ...

  • Like 1
Link to post
1 hour ago, sad vampire said:

Use a hairdryer

 

Dude, haven't got one as don't need one and if I borrow the Missus's I'll never hear the end of it ...

Link to post
3 hours ago, trisaki said:

Try doing  a ecu reset 

Cheers, but how would this fix the problem.

I'd been under the impression the ABS-system is doing a feedback-loop (as described by Andy m), so how would a reset of the ECU interfere with this?

Link to post
trisaki

All I said was try it , it takes 20 mins or so  , all you do is disconnect  the battery then reconnect  say 15/20 mins later start it without  touching  the throttle  run it till the fan kicks in , wait for the fan to stop then turn off using the kill switch , won't hurt to try ! Also you can check tightness  off battery bolts as these seem to come loose ! and also do a voltage  check  , , all worth a try 

  • Like 2
Link to post
SteveThackery
4 hours ago, trisaki said:

All I said was try it , it takes 20 mins or so  , all you do is disconnect  the battery then reconnect  say 15/20 mins later start it without  touching  the throttle  run it till the fan kicks in , wait for the fan to stop then turn off using the kill switch , won't hurt to try ! Also you can check tightness  off battery bolts as these seem to come loose ! and also do a voltage  check  , , all worth a try 

 

There is no such reset for the NC.  The procedure you describe may apply to other bikes, but not the NC.  I know this because I've asked a Honda tech, plus there is no such reset mentioned in the official workshop manual.

Link to post
Andy m

ABS sensors can be checked with a multimeter. Better to do it at the last connector before the ECU if you can. 

 

Do a resistance check, they are only coils. Should be 15 Ohms IIRC, but any number is good they fail by going open circuit because the wire is hair thin. 

Set the meter to AC volts. This turns it into the world's crappest functional oscilloscope. Spin the wheel and if you get over half a volt and a steady reading for a steady speed you have a signal. If it flickers like your Grans telly you have dinged pole wheels or bearings on their way. 

 

The warning light is a switched ground. Honda usually use an orange and blue wire. The ABS grounds this wire when there is a fault. A short in this makes the dash think the ECU is doing it. Given the dash is more exposed, this connection is a candidate for water ingress.

 

The CB has a blink code system. There is a red blanked plug under the seat/RH side panel. You link the green and brown and the ABS light starts morse. Long-long-short is 21 : runout on the front pole wheel etc. I imagine the blink code is the same for the NC so if you can get these out post the number and we can go from there. 

 

The fact cold water brought this on still screams voltage and wiring, so double checking the battery clamps etc. is IMHO still worth a shot. 

 

Andy

Edited by Andy m
  • Like 3
Link to post

Especially as we now know the battery terminals were disturbed only a week ago.. :) 

  • Like 2
  • Thanks 1
Link to post

Cheers guys,

I won't have time to sort things out until next week, but will let you know what's happening.

  • Like 2
Link to post
steelhorseuk

As Andy's (ACE) last sentence ..... Please just check the battery terminal cables are nice and tight!

I had this problem with electrics on a previous occasion. You never know if they worked loose since you changed the battery recently (as Tex says) ........

Link to post

How about that ...

 

... finally got to have a look at the ABS warning light problem today. Checked if it had sorted itself out, still same problem. Did a lot of reading of the Workshop Manual and decided to use the bike for the time being (and until I had the chance to order the two connectors mentioned in the manual) just without the ABS working.

 

Rode home, with the ABS warning light on, and then suddenly noticed that it had gone out whilst I was focussing on traffic. 

 

Did a couple of start/stops with engine on/off, etc. ... looks like all back to normal ... how bizarre!

  • Like 3
Link to post
Andy m

Glad it's sorted

 

Battery voltage or water in a connector IMHO. The Italian tune-up charges the battery and steams out the connectors. If it comes back on on Monday its the battery. 

 

I'd blather it in WD40 and/or get the silicone spray out for the connectors too. 

 

Andy

  • Like 3
Link to post

Amazing , Honda have manufactured a self healing motorcycle. Now that is build quality :0)

  • Haha 6
Link to post
3 hours ago, Tonyj said:

Amazing , Honda have manufactured a self healing motorcycle. Now that is build quality :0)

Anyone running old Brit iron will know the phenomenon of parts healing. When something is worn you get a replacement part, often used, and put the old worn one on the shelf "to heal". At some point in the future you can be sure that it will be in better condition than the one which is now on the bike, so gets swapped around again. I have boxes of old Brit bike parts healing away merrily. :lol:

  • Like 3
  • Haha 3
Link to post
fred_jb
On 13/02/2019 at 11:51, embee said:

Anyone running old Brit iron will know the phenomenon of parts healing. When something is worn you get a replacement part, often used, and put the old worn one on the shelf "to heal". At some point in the future you can be sure that it will be in better condition than the one which is now on the bike, so gets swapped around again. I have boxes of old Brit bike parts healing away merrily. :lol:

 

Not just biking Brit iron either, also old Brit cars.  When I had a Midas kit car I had quite a few spare parts stripped from other dead A series engines and was never quite sure which of a selection was the most healed!  On one trip we had to bump start the car to get it on the ferry due to a problem with the starter motor. At the first camp site on the other side I fished out the spare one I had chucked in the boot, having had some suspicions about the state of the one I originally fitted, and swapped them over.  Fortunately on the A series engine the starter motor is one of the easier bits to replace.  On an old Austin 1100 I ran for a while I had replaced the clutch and obviously not torqued up the flywheel bolt sufficiently as it developed a serious rattle while some way from home.  It turned out that the flywheel assembly was coming loose.  A difficult job, but I managed to get at it and tighten it up enough to get home.  As befits someone running old bangers, I must have carried almost my entire tool collection around with me in those days!

  • Haha 3
Link to post
  • 2 months later...
Paultech87uk

I had this problem on my 2014 nc750x, turned out to be a slight bend in the abs ring (likely from disc lock) and light rust, wire brushed off rings and bent out the kink. 

Hope this helps

  • Thanks 1
Link to post
SteveThackery
On 2/12/2019 at 17:57, Andy m said:

 

Battery voltage or water in a connector IMHO.

 

I don't believe it'll be the battery voltage.  Even with a seriously knackered battery, once the engine is running the alternator immediately pushes it up to the regulated 14.4V.

 

It's water in a connector.

Link to post
Andy m

A low voltage fault usually latches once its seen it. It's often put into failure as it cranks. With trucks and cars where the light goes off stationary you will see it come back on. With an off at 5 kph light (which we had on 4+wheels until 1999*) you may spot a flicker. You may also find it stays on first thing in a morning but after tea break goes off OK. 

 

*the great ABS warning light debacle got me a quarterly trip to London for 3 years. Some manufacturers were using yellow which makes sense as it reverts to a normal system. It's like a fuel warning, it comes on you sort it out. Red also makes sense because it's a safety system. Off at 5 kph gives you a conundrum if the light is red. Why would you drive away if a huge red stop is showing on the dash? This is like a low oil warning This however is the only way to see if it's just a sensor or voltage fault from the last run, so driving half a mile with the light on may avoid towing a petrol tanker off the M25 in rush hour. SMMT do a lovely buffet and it was great for Christmas shopping 😁

 

Andy

  • Haha 1
Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...