Volvo 670 ABS light

Last time it happened to me it was loose sensor. I've pushed it in, problem solved. Previous 3 times I've ended up with new bearing set at that corner. It can be many things, and you should have it checked soon.

 

not really

ABS only works when you panic stop...BUT your ABS on that wheel isn't going to work and the rest of the ABS system may not work... you'll still have brakes just not the ABS.

just about any truck stop can fix it, for $50-$110

it is a DOT violation for that light to be on.

 

Data erratic could be just a loose sensor, but it could be loose or failing wheel bearings. It could also be a bad tone ring. Normally ABS problems are not a big deal to drive with, but erratic signals can be a wheel end issue, so it could be risky in your case. Best to get it checked ASAP, probably not a big deal with only 1 event, but better safe than sorry.

 

ta can plug into and read the code.... a tone ring is not the same code as a bad of loose sensor.... and yes water can get into the wiring and do that and when dry it will be fine

 

in heavy rain, snow slush and grit can cause the sensor to give you an error like that.Sometimes just pushing it will solve it too.

 

It can be the same code. I've seen corroded teeth on a tone ring set erratic signal codes. Checking tone ring is one of the checks when diagnosing an erratic signal code. If it is missing a tooth altogether it usually sets a code specifically for damaged tone ring, but that's only if it picks up a pattern of a missing tooth. Worn down teeth can make weaker signals that get strong enough as speed increases and not develop enough for a pattern to pin point it.

They have several codes for different types of failures and often the trouble shooting overlaps, especially with mechanical faults. Sure TA can tell him the code that he already has, it's on the dash. The next step is to troubleshoot it and here's what you do with FMI 2 on a wheel speed sensor:

1. Adjust sensor to contact exciter ring.
2. Rotate wheel and verify a minimum of .25 VAC sensor output at ~ 0.5 RPS
   
3. Verify condition of sensor head.
4. Verify mounting of exciter ring and condition of teeth.
5. Verify proper bearing end-play.
6. Verify condition and retention of clamping sleeve.
7. Verify sensor lead routing and clamping.
8. Check for corroded/damaged wiring or connectors between the ECU and the wheel speed sensor.

 

to be MORE accurate the dash display will only show the main fault.... other codes may not show up on the display but are in the system.

my truck showed a abs fault "Wheel sensor erratic data " but when it was pulged in the code that was the reason for the erratic data was not for the Wheel sensor it was for improper tone ring.

my truck is in the dealer right now.... the dash ONLY showed 1 code on the dash BUT when it was plugged in 6 other codes showed up.. codes that the dash WILL NOT SHOW

 

The 2 basic types of faults are active and inactive. Active is what is displayed on the dash and the reason the warning light is on right now. Inactive stays stored and can help in more complex problems, but the age needs to be checked, I've seen people try to diagnose faults that were months or even years old, that just wastes time and a customers money. I've known dishonest shops to charge for diagnostics on faults that were years old and were obviously fixed, then customer just never had the fault cleared. Recent faults can be related, but the active code is the current fault that is causing a warning light right now, that is the "main" fault that you want to diagnose first. This is for ABS issues, engines can and will show many faults differently, many dash displays are J1587/1708, where most engines are J1939, so the dash cannot show all faults and even sometimes translates them goofy. ABS systems are still J1587/1708.

Engines can log some minor faults with no warning light or fault on the driver display, Cummins high coolant temp least severe level is one of them. This fault can show up several times in the ECM, but never warn the driver of any issue because it's not really an issue. If the code stays active long enough, it will set an FMI 31 and turn on the warning light for condition exists.

But we're talking about ABS here, a pretty simple system by todays computer control standards.