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How do I fault-find a speedo/odo +ABS problem?

barry.b

Just got it firing!
GT Famiglia
Joined
May 26, 2012
Messages
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Location
Brisbane, AUS
Hi all. 2006 Norge with ABS (first year model, 2v) 60,000km on the clock (plus recent "extra")


30 minutes into a 3 week and 2500 km trip the ABS light flashed on, the speedo dropped to zero and the "SERVICE!" error came up on the dash. Apart from an occasional flicker of the speed and odometer, it was pretty much no one home. And - I found out the hard way - the ABS is no longer working.

Every time I turned the ignition on, within seconds the ABS + warning light came on. Rarely there's a flicker.

A weird addition was an hour after the initial fault, the fuel gauge also went stupid, but it came good after a couple of hundred kms' and been no problem since.

Fault-finding done so far:
- all fuses checked for continuity, and the fuse holders inspected for corrosion. Nothing seems to be amiss.

Armed only with my eyes (and simple tools) and a multimeter ... (no, I don't have a spare dash to swap out ... and besides ... #codes)

- How do I check to see if the front and rear speed sensors are at least producing a voltage that the ECU can read? What's an easy way to take a reading? This will tell me if the sensors are the problem or look elsewhere.
- Where's the ECU multipin connectors to see if they're seated correctly? The fuel gauge going stupid the once is suspicious...
- In what way does the speed sensors affect the ABS? How does it work: do the speed sensors feed into the ECU and in turn the ECU controls the ABS? That ABS has been really handy and I don't want to live without it.

I've been going through the archives here, and nothing is feeling like it's the same situation as me: it's not ingress because it's been 3 weeks of hot weather with very little rain. Slow onset of corrosion may be possible, as might wiring damage. I'd hate to think a new ECU/dash is needed: there are no 20 year old Guzzi parts to be had anywhere near me.

Thanks in anticipation
Barry B in Brisbane, Australia.
 
If you want to read, that is discussed in the service manual. How to check, Ohm readings for sensors, even each pin connector.
There is a manual in download.
You could also do a search, common issue well discussed on end.
 
This has been covered a million times.

First, remove your battery and take it to a local auto parts store and have the battery LOAD TESTED.

Almost certainly, it will fail.

All Italian motorcycles are extremely sensitive to erratic power.

When you suddenly develop all sorts of electrical issues in rapid succession, 99% of the time, they are traceable to a battery that fails a load test.

Do this FIRST then report back, or not. Your choice.

If you do a search on LOAD TEST, you can find all sorts of people who ignored me, spent small fortunes on useless parts and tens of hours, chasing phantoms to no avail.

When they finally relented and load tested their battery which invariably failed, and installed a new high quality battery, cleaned their battery cables fully, and removed the negative ground from the engine and cleaned both the cable and the attaching bolt fully, things returned to normal.

🤷‍♂️

Good luck.
 
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The ABS control unit under the seat reads the signals from the two wheel sensors. It then sends the information from the pin 3 with a frequency modulated signal to pin 24 of the engine control unit via the gray/white wire.
This signal is present only if both wheel turn, so is difficult to check it.

The wheel sensors generate a voltage for each hole of the flying wheels.
The best way to check them is moving a wheel at time and verify with an oscilloscope the correct waveform.

In your case, check the connections and if the wheel sensors are clean and with correct gap from flying wheel. Moreover check if the lyng wheel are flat.
Once an ABS sensor of my car reported error due to a metallic sliver attracted by sensor.
 
In this case, very sceptical it's a failing battery. I've just had three weeks and 2500km of holiday touring like this and the ABS/speedo issue is the only fault. I'll recheck (again) the battery terminals and I won't ignore wiring or ground issues but, to be honest I'll be putting sensor checks up much higher than a failing battery. If I had trouble starting the bike these last weeks, that'd be different
 
If you want to read, that is discussed in the service manual. How to check, Ohm readings for sensors, even each pin connector.
There is a manual in download.
You could also do a search, common issue well discussed on end.
Service manual in the downloads, for the win! Excellent, that will do nicely. Thanks for the direction
 
The ABS control unit under the seat reads the signals from the two wheel sensors. It then sends the information from the pin 3 with a frequency modulated signal to pin 24 of the engine control unit via the gray/white wire.
This signal is present only if both wheel turn, so is difficult to check it.

The wheel sensors generate a voltage for each hole of the flying wheels.
The best way to check them is moving a wheel at time and verify with an oscilloscope the correct waveform.

In your case, check the connections and if the wheel sensors are clean and with correct gap from flying wheel. Moreover check if the lyng wheel are flat.
Once an ABS sensor of my car reported error due to a metallic sliver attracted by sensor.
Errr ... oscilloscope: don't have one, and it's not the sort of thing I'd add to the touring toolkit. Hmm... unless there's a pocket adapter I can add to my mobile phone?

Looks like the best I can do is check for continuity.

Thanks for the detail how the parts are connected. That helps a lot.
 
In this case, very sceptical it's a failing battery. I've just had three weeks and 2500km of holiday touring like this and the ABS/speedo issue is the only fault. I'll recheck (again) the battery terminals and I won't ignore wiring or ground issues but, to be honest I'll be putting sensor checks up much higher than a failing battery. If I had trouble starting the bike these last weeks, that'd be different

Hmm,

I give you an answer, that costs literally nothing to check, which has been verified and written about here so many times here over the last 14 years that I've been here that it's comical, and you summarily dismiss it. Right. Got it.

Truly, it makes more sense that all of a sudden, your dash is throwing errors galore, and then goes in and out, and your ABS sensors go out at the same time, etc. What a magnificent confluence of linked events.

FWIW: I've seen hundreds of batteries that could start a motorcycle, but failed a load test but what the hell do I know. Silly me.

41 years of working on motorcycles as a professional mechanic, my own shops, and I currently own and maintain 10 Moto Guzzi motorcycles and a collection of over 20 motorcycles in total...

Ok. Sure thing. Have at it. You've figured it all out already.

Please... Go chase your own tail and have a great time with that.

Honestly though, I want to sincerely say thank you for reminding me why I stopped giving people help for free here. I thought things might gave changed but obviously I was mistaken.

Always... So many like you who ask for help and then refuse to listen at all.

GTM and I and many of the other skilled mechanics here, are used to this. No worries. Not my circus, not my monkey.

Good luck to you.
 
Hmm,

I give you an answer, that costs literally nothing to check, which has been verified and written about here so many times here over the last 14 years that I've been here that it's comical, and you summarily dismiss it. Right. Got it.

Truly, it makes more sense that all of a sudden, your dash is throwing errors galore, and then goes in and out, and your ABS sensors go out at the same time, etc. What a magnificent confluence of linked events.

FWIW: I've seen hundreds of batteries that could start a motorcycle, but failed a load test but what the hell do I know. Silly me.

41 years of working on motorcycles as a professional mechanic, my own shops, and I currently own and maintain 10 Moto Guzzi motorcycles and a collection of over 20 motorcycles in total...

Ok. Sure thing. Have at it. You've figured it all out already.

Please... Go chase your own tail and have a great time with that.

Honestly though, I want to sincerely say thank you for reminding me why I stopped giving people help for free here. I thought things might gave changed but obviously I was mistaken.

Always... So many like you who ask for help and then refuse to listen at all.

GTM and I and many of the other skilled mechanics here, are used to this. No worries. Not my circus, not my monkey.

Good luck to you.
c'mon man, don't be like that. I didn't dismiss it, I said I was sceptical. It does cost something to check, at least properly - where I am to get to a place that can do it is a real hassle, and it's far easier to dismiss all the other checks I can do at home first.

And if you want to bring "history" into it, I've got two perfectly good batteries decaying in the garage because "battery" was the first conclusion people came to with "Click-No-Start". I'm now convinced that it's the cheap (undergauge) wiring Guzzi has used + the convoluted wiring to the key/ignition switch/ECU/starter motor, but on my Norge, it only happens when the air temperature is very high and/or I've given the bike a real flogging on a not-cold day. It would "Click-no-Start" every time when touring Western Queensland (think Mexico in Summer) and start perfectly an hour later when it cooled down and only failed twice in three weeks and 2500kms during this Tasmania trip (think Canada in summer). Makes perfect sense: wiring get hot, increases resistance, drops the voltage to trigger the starter motor. Now that my Breva 750 is getting up to 200,000kms, it's also starting to do the same (so I'll do the same fix - secret external starter button wired directly to the starter motor) - it's possibly tired connectors or individual copper strands breaking within the wire. "Italian Quirk" and live with it.

So I'm not saying you're wrong, but if I can check easy stuff first and it's still a mystery, then I'll try and arrange a shop to get the battery properly load tested (because I don't trust my ham-fisted way of looking for a voltage drop on my el-cheapo multimeter when I start the bike - I don't trust my reading of the - seemingly - insignificant voltage drop I'm seeing).

I'm still thinking one of the speedo sensors may have been compromised or worked loose. The bike was "bikes only" freighted to the holiday start point which involved loading/unloading in two trucks on a 1500km road journey and an 8 hour vehicle ferry across a typically rough sea, but I'll look for proof first. Also I had the rear brake line replaced running under the CARC (reasons) to the ABS which is next to the rear sensor. At the moment, I'm stuck waiting for a cyclone to pass and it's safe to be outside working on the bike.

here's an opportunity: if the bike starts easily and rolls off down the road just fine, but the ABS/error light and the "SERVICE!" warning on the dash come on within 100m, what else should I look for that a failing battery is the cause?
 
I'm sorry.

I've never been to Australia but my experience in the USA and Italy is that literally any auto parts store that sells batteries, will have a load tester. They all offer load testing to determine if a battery is good or not for free. Costs nothing to hook a load tester to the terminals, squeeze the trigger, and read the gauge.

I're read from other Australians who have had this done as I described.

Load testing is not the same as reading voltage with a volt meter. Completely different.

Nevertheless, I gave you the info. I've done what I can for you.

I hope you figure it out.
 
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The interrupted staring has little to do with the battery. If you chased that, you were talking to the wrong people. Like you say it is a wiring issue. Years ago Mike Haven came up with a fix, easy to find if you search this site. The problem was peculiar to the Norge/Breva/Sport, all on the same "platform". My old Griso has never had these issues.
What fault codes are you getting at the dash?
If you get most of the 8 faults, it's most likely your battery. I have gone through the following twice over the years with my Breva.
As nuisance alerts become more frequent, I have checked all connections around the bike (cleaned/corrosion block), then it is time for a new battery. Last July I replaced the 3 year old battery (I ride through the winter, not a single alert since). I had that battery load tested. It passed (I got the print-out). So I pass it on to the Griso, where it will function nicely for another 3 years. The now 6 year old battery from the Griso goes to the re-cycler. Both bikes show 120K km. These are run of the mill Powersport AGM batteries. They live on a Battery tender.

This forum is like the American Library of Congress. Get to know it and how to search. I have personally given up on owners clubs and other forums. Too many opinions and blind brand loyalty, and not enough facts.

And please, if you find something worth sharing here, come back and let us know.
Best of luck to you.
 
FWIW: Nowhere above did I state that a "Click start" was the battery at this time.

It is the sudden appearance of multiple dash errors snd warnings, etc. The cutting in and out etc. These are the indications of an internally damaged battery.

This being said, you will experience the very same "Click start" issue in a bike equipped with a hard start relay, but which also has a battery in a poor state of charge or dead cells.

Hence LOAD TESTING the battery to determine internal resistance and cell conditions.

The amount of pushback at this primary diagnostic technique, which has been written about exhaustively here, is stupefying.
 
As has been mentioned earlier (and caused something similar on my Eldorado) is to remove and clean each wheel sensor , it's kinda
surprising how small a piece of metal stuck to the sensor caused my problem .
 
What fault codes are you getting at the dash?
ah ha! Fault Codes! Back in the day I used to write software so lived by error codes.

Thanks for the push. This is getting me onto the right track in what I'm looking for.

We've been through a cyclone, the place is a bit of a mess and bike packed away safe. Now that the sun is out, will have to learn how to read them from the dash (it looks like I don't need a laptop with special cable like the Cali 1400's).

According to the ELE-SYS-8 page of the workshop manual I'll be looking for "Vehicle Speed Error ECU 56"

and if it is, then it's on to BRAK SYS-3 to show where the sensors are and BRAK SYS-9 to -13 for the diagnosis.

BRAK SYS-9 does mention the 10A and 40 and 25A fuses, so there's value to recheck those again.

"Moto Guzzi: making mechanics out of riders since 1921" I'd rather not be learning these new skills - time poor/enough on my plate - I just want to enjoy that brilliant engine and shaft drive and handling ... but the best Guzzi mech in town refuses to touch this because, while he's a whiz for keeping LM's, SP's, T3/4/5 and orig V7's (and Ambassadors) and 1990's Cali's on the road, it's all getting a bit too high-tech now-a-days and he doesn't want to know (and there's no one else in my town that I'd trust to work on a Guzzi, nor would they want to)

gawd help us with the forthcoming "Ride by wire" for the next batch of V100's...
 
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As has been mentioned earlier (and caused something similar on my Eldorado) is to remove and clean each wheel sensor , it's kinda
surprising how small a piece of metal stuck to the sensor caused my problem .
yeah, the vast majority in fault finding is simple stuff that's easily explained ... "D'oh!"
Another one in this case could very well be the fuse holders and corrosion (since the 10, 40 and 25A fuses are fine)
 
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