ST fault codes

Joined
Mar 26, 2022
Messages
3
Age
58
Location
Brisbane
Hi group. Newbie here. I had my ECU remapped and then 2000km latter my F1 light came. l could feel the engine pull up slightly when the light came on, It happened about 1km into a run on a motorway. The next day the same thing happened but the speedo and odometer also stopped working. About 2km latter, they were working again. Next day, the speedo and odemeter weren't working from start up and took about 10km before they started working again. The F1 light would always come on 10 minutes into the ride, regardless of RPM's. l very rarely rev the bike above 4000RPM. l then went 2 days of motorway riding with no issues then on the third, the F1 light came on and the speedo and odometer stopped working again. When l pull up on the bike and let it idle, the F1 light with give 1 long flash then 1 short flash. l sprayed contact clean on the ECU and control box plugs which did nothing except bring the F1 light on 2 minutes into a test ride. l'm guessing a wiring problem after disturbing the ECU and associated wiring in the duck tail when the bike was re mapped. Has anyone had a similar issue. Can someone please decode the long and short flash. Thanks in advance RJ
 
To answer the question -

One long, One short is code 11.

Loose or Poor contact on vehicle speed sensor
Open or short circuit on vehicle speed sensor
Faulty Vehicle speed sensor.

But my suspicion would be with whatever was disturbed, and I would be looking very carefully at the mating parts of the multiway connector to the ECU before worrying about anything else.

I don't know which year model you have - but the front wheel speed sensor is the Bk/P wire and the Gn/Or wire, and both feed into the ABS unit if the bike has ABS.

I'm not going to ask why you had it re-mapped. No. Not me. I wouldn't ask that. But if you felt the urge to tell ........
 
Last edited:
To answer the question -

One long, One short is code 11.

Loose or Poor contact on vehicle speed sensor
Open or short circuit on vehicle speed sensor
Faulty Vehicle speed sensor.

But my suspicion would be with whatever was disturbed, and I would be looking very carefully at the mating parts of the multiway connector to the ECU before worrying about anything else.

I don't know which year model you have - but the front wheel speed sensor is the Bk/P wire and the Gn/Or wire, and both feed into the ABS unit if the bike has ABS.

I'm not going to ask why you had it re-mapped. No. Not me. I wouldn't ask that. But if you felt the urge to tell ........
Thanks for the reply. 2008 so ABS model. I searched youtube for fault finding vids after l posted here and discovered how to decode the flashes. l'm heading to a night shift now so l'll check the speed sensor connection tomorrow morning. Hopefully it's just a loose or dirty connection. My ST has a set of cans and a K&N air filter so l put her on the dyno just to check if she was running too lean. On the stock map she was lean in the lower revs but the mixture improved as the revs increased. My bike spends the majority of time on the motorway to and from work and rarely gets above 4000RPM so the dyno guy put in a new map which addressed the lower RPM lean mix. There was no gain in power, rear wheel HP is still only 120, but the ride felt like it had improved, a little more crisp in the lower revs. :)
 
Those are the symptoms that result from an intermittent speed sensor signal.
The cause of an intermittent signal can be the result of a defective/intermittent speed sensor or a problem in the wiring between the sensor and the ECM. Rarely is the cause due to a defective ECM. Since you have recently disturbed the ECM connectors, you should start by checking all of the wires and connectors there.
If you can not identify any wiring/connector problem between the speed sensor and the ECM, the most likely cause is the speed sensor is beginning to fail.
 
l'm heading to a night shift now so l'll check the speed sensor connection tomorrow morning.

My comment was implying that maybe it is the other end of the wires - ie at the ABS multiway connector that may be at fault since that is the end that has been disturbed. Presumably the info is also passed to the ECU - but there is no info that I can find that says how it is passed. Just check the connections. Clearly it is getting the info some times, not at others.
 
Problems after maintenance usually occur where the human was last. Like others have mentioned check the connectors at the ECU and look for bent pins on the ECU.
FI code 11 is the vehicle speed sensor located on the lower RH side of the rear engine cover. It is not connected with the ABS system.
 
Your looking further than you need to see....
Your speed sensor switch is failing.
Its a really easy replacement, and does not cost much.
When they start dying, you loose your speedo/tach and lights for a moment, then they bounce back on.
They usually do this a couple times before they die completely.
I would urge you to replace the speed sensor switch before you start doing anything major (that you may have already done) to the ECU or wire harness.
When your speed sensor switch fails, it will also throw the code your getting :doh1:
As far as the re-mapping thing....ST's run very lean from the factory, and you putting a K&N filter in just made it that much more so.
These bikes don't normally run as well with K&N filters in them. The mufflers should not matter.
Your ECU is trying to correct too much stuff.
 
Those are the symptoms that result from an intermittent speed sensor signal.
The cause of an intermittent signal can be the result of a defective/intermittent speed sensor or a problem in the wiring between the sensor and the ECM. Rarely is the cause due to a defective ECM. Since you have recently disturbed the ECM connectors, you should start by checking all of the wires and connectors there.
If you can not identify any wiring/connector problem between the speed sensor and the ECM, the most likely cause is the speed sensor is beginning to fail.
l've ordered a new speed sensor from CMS. Should be here by early next week. When checking the old sensor l was a little worried how close it was to the exhaust. These bikes get very hot under the plastic and l'm guessing Queensland summers would make it a lot hotter. How do those electrical components cope with the heat :)
 
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