ABS indicator stays on

[fleetmechanic]

2009 FLHTP with about 34,000 miles.   ABS indicator lamp stays on all the time and the WOW test shows "NO RSP"
as the trouble code.  The electronic diagnostic manual says to check continuity in the wire from the ECU to the tachometer and that's about it.   I will do that but does anyone know of other items to check?  I'm guessing this might be another pinched wire by the frame neck issue.

[hdbikedoc]

make sure engine kill switch is in run position before do wow test

[fleetmechanic]

Thanks, but the kill switch is always on when doing the test.

[thunderrat]

When the ABS light illuminated on my 09 FLHT it was due to a pinched wire up by the steering neck. Also showed some other codes but don't remember exactly what they were................ted

[IronButt70]

Possible wheel bearing not sending signal?

[rigidthumper]

No RSP during ABS portion of WOW test is usually one of the three: blown ABS fuse/bad connection, failed ABS diode pack, or failed ABS ECU unit. One other option is a break in the grey wire ( ignition wake up) between ABS ECU pin 19, and the ignition fuse.

[fleetmechanic]

No RSP during ABS portion of WOW test is usually one of the three: blown ABS fuse/bad connection, failed ABS diode pack, or failed ABS ECU unit. One other option is a break in the grey wire ( ignition wake up) between ABS ECU pin 19, and the ignition fuse.

Thanks.  Now I have a list to work with. Are the diode packs prone to failure?  It's a cheap part but I've not seen any fail before.

[chaos901]

Mine was on all the time on a 2008, turned out that the wire to unit at the rear axle was cut in two.  Apparently the person that installed the tire (me) did not get the cable routed correctly.

[fleetmechanic]

All the wiring from the ECU to the tach and the ignition fuse checked out fine.  ABS fuse was OK. Diode pack change made no difference.  There are no codes about wheels or sensors to go along with the "NO RSP" code.  Diagnostic manual shows replacing the ECU as the next step.  Hoping to avoid that.

[road-dawgs1]

Sometimes wires inside a wire loom can be problematic and pinched/broken just enough to cause problems but are hard to recognize as broken. Hope you find the issue.

[fleetmechanic]

Continuity from the ECU to the tach light checked fine but I sliced the conduit by the frame neck to check wire condition in the loom.  All wires looked fine, no signs of stress.   Still looking.

[chaos901]

For curiosity, do you have a computer that will "work" the ABS unit, such as when you bleed the brakes.  Might hook it up just to see if it can recognize the unit and make it operate.
Just a thought.

[Pirsch Fire Wagon]

The ABS Lamp "on" indicates the System has been disabled due to an issue. Just means there is no ABS Functionality until repairs are made.

Do you have CPU based program to pull codes from the ABS CAN?

Check the ABSM Plug for Voltage (+) and (-)

On RARE occasions, the Wheel Bearing Tone Ring can become damaged. A good visual inspection will identify.

Locate the electrical connector from a particular the wheel speed sensor which is near the frame at the ABSM. Have someone Turn the wheel. A/C voltage should increase. If you have no voltage, check that circuit. If no problems are identified replace the Sensor.

If all the above "passes", the Module is the most likely culprit.

[Yellow09SERG]

Just had to replace the electrical module on my 09 with the same issues.

[fleetmechanic]

I noticed today that when the ignition is turned on with the forks to the left the light flashes normally even though NO RSP still shows as a code but as the forks are turned to about straight ahead the light returns to steady on until power is turned off.  I'm going to retest the wiring passing the frame neck.

[jty]

Although not likely to thtoe NO RSP, on my 2008 FLHRC, both ABS sensor connectors were really low quality, open and close few times and the leads bend and lose spring force. Threw me a proper code, thou.
No rsp means that information from Abs module to display via Light green/Violet data bus wire is not available. No disrespect but are you sure the No RSP is from Abs, as blinking light means information is available.

[fleetmechanic]

WOW test with light flashing still shows NO RSP in the ABS test mode.

[Pirsch Fire Wagon]

I noticed today that when the ignition is turned on with the forks to the left the light flashes normally even though NO RSP still shows as a code but as the forks are turned to about straight ahead the light returns to steady on until power is turned off.  I'm going to retest the wiring passing the frame neck.

there was an issue with wire on the inside of the fairing being too taught and breaking. Although, I do not recall the years affected.

[Pirsch Fire Wagon]

WOW test with light flashing still shows NO RSP in the ABS test mode.

The No Response indicates the E.C.M. can not communicate with the ABS Module. This would indicate either an issue with wiring between the two or a Module Failure of either one.

[fleetmechanic]

I rechecked all wiring to ECM and front end and all ok.  I then replaced the front wheel bearings because we've had some of the ABS bearings fail in the past as we run in a lot of ice and snow  No help.  But now there's a code in the ECM part of the WOW test that is U1040.  I don't see that code anywhere in the Electronic Service manual.  Anyone know what it means?

[cig]

According to fuel moto U codes indicate a communication problems with the modules

[fleetmechanic]

Yes, I looked in a 2011 Elec. Diag. manual and it was there.  Looks more like the ECU may be the problem.

[aussie123]

Mate if it is a major component like ecm etc ,, then that is unfortunate ,,,,

I had similar problem, ie , abs light staying on... but I had a code that said error was front not rear...
I took the punt that the abs bearings and sensor wire were good, and went after  broken/ damaged wire from connector to abs module...
Could not find any physical damage from connector and going up to main cable duct.. Was going to remove tank etc , and check wiring in duct , but thought I would a continuity test of wires from connector to abs module with multi meter.... 
Remove main connector from abs module,,, find the two wires that were for the front sensor,,, Get a small paper clip,, make it in to a U shape to fit wire locations, (ie , short them out)....
Go to front abs connector with multi meter and test for continuity ..... No continuity ......

I was lucky,, the fault was just outside the main cable duct , (where a fault is common), so I had enough room to cut and splice without taking the tank off etc ..... All good ....

If I read you first post correctly ,, your error code does not say front or rear abs fault .... So that may point to the ecm etc may be the problem, not wiring or sensor .....

[Pirsch Fire Wagon]

According to fuel moto U codes indicate a communication problems with the modules

"U" DTC's are SAE generic code (applies to all OBD-II systems)

Faulty / intermittent vehicle speed sensor / connections
J1850 / SCP Bus wiring intermittently open, shorted to power or ground
Faulty / intermittent connection at the Powertrain Control Module (PCM)

Any of these can be triggered by removing a connector, Battery, or other power source from the Modules. If you don't want them triggered, remove main fuse when troubleshooting.

[fleetmechanic]

Before ordering a 500.00 non-returnable ECU module I decided to ride the bike to the dealer and see if the DigiTech showed anything else.  Well, it showed  several front wheel related stored codes and I went to the left side of the frame neck and found an old tired splice in one of the front sensor wires from the original PD that owned it..   Spliced in a new section of wire and light goes out and ABS works.  WOW test still showed NO RSP until the Digitech cleared it.  We've had these  wires fail before but WOW always showed some front wheel codes.
I've got and old Kent-Moore Scanalyzer but the software cartridge was never updated after ABS came into use.  Are there any reasonably priced portable scan tools that will show the ABS codes on these bikes?

[chaos901]

Daytona Twin-Tec has a version that reads ABS, load it onto a laptop and hook the laptop to the bike. 

[rigidthumper]

Depends on what you consider reasonable- The Centurian from Techno Research is very handy,  works like the HD Digital Tech does.