ABS Light With No Codes

[Doubeleive]

Thanks for the advice! I just bought it and my trusted mechanic didn't feel anything excessive in the front end. There was a tiny amount of play at the pitman, but not a lot. The inner tie rod did have excessive play and was replaced.

I have pads and rotors coming from Rock Auto in the next day or so. My plan is to pull the sensors, inspect, clean and install the new front brake rotors and pads. If if cleaning the sensors doesn't take care of it, I'll go for new hubs with sensors up front and see what that does. Thanks again. I'll know by sometime next week, what happened or was found on inspection.

Sometimes they do not have play but will make noise when the wheel is spinning, either a grinding noise or sometimes a tick like noise like a ping-ping sound or any kind of scraping noise, they should be dead silent ideally.

 

[Hobert]

Update:
Sunday 11/7...
ABS light and chime still flashing, staying on a while, turns off for brief stretches and the cycle repeats for as long as I am driving over 55 MPH. Get off the highway, driving local roads 30 - 45 MPH and everything is peaceful again.

New downstream O2 sensors cleared that code, which has remained off for two days.

I think at this point, I can rule out the possibility that the O2 sensors or the CEL code they created had anything to do with what the ABS light/chime is doing. Not related.

I am due for new brakes. I will start with replacing the front pads and rotors. I'll be removing the ABS sensors to clean them of any debris and will brush off any rust that may be on the hub. See if that does anything. If not, front ABS sensors are really pretty cheap. I may just buy new front sensors with my front brakes anyway. No sense in taking rotors off twice for $30-40 bucks. Not worth the added time...

I had a 2001 yukon XL, in 276000 miles I had this issue twice. Each time I had front hubs replaced twice fixing the problem.

 

[MassHoe04]

I had a 2001 yukon XL, in 276000 miles I had this issue twice. Each time I had front hubs replaced twice fixing the problem.

I may end up doing hubs, but current cash flow is forcing me to split into smaller jobs. I'll be doing front rotors, pads and giving a try on ABS sensor clean this week. It may be a couple more weeks for hubs, when I have funds.

 

[MassHoe04]

I may end up doing hubs, but current cash flow is forcing me to split into smaller jobs. I'll be doing front rotors, pads and giving a try on ABS sensor clean this week. It may be a couple more weeks for hubs, when I have funds.

I managed to find my Zurich scanner does read ABS codes. Not live ABS data, but at least it sees the codes. History was C0225. Still happens mostly at 55+ MPH. I pulled the connector and sprayed with BrakeKleen, in case there was dirt or oil on there. See what happens tomorrow...

 

[MassHoe04]

No change after cleaning and snapping the connector tight. Still pinging/dinging at me on the highway, but not after I slow down off the highway.

I read somewhere tire size could throw off the system? I did swap out to some stock rims. They came with slightly smaller than stock (245/75 R16), but they are all the same size. The C0225 code indicates only left front issue (open circuit).

I am still hoping it is just the ground to the chassis from the - battery, the body to block ground strap, or the EBCM.

I looked deeper into the menu and there are codes there, but no stored codes or active check engine light. I have been using cruise control, brake lights work and there doesn't seem to be anything wrong with the transmission shifting. Are these old codes that have been fixed, maybe? It also listed a couple of evap codes, but here are the ones in that history related to things that all seem to work fine... Are these active or just historical?

If active, are they possibly related to possible poor grounds?

 

[Walchit]

I'm having ABS issues right now too. Check the wire really good on that sensor, mine was broken in at least 2 places. I soldered one, then just bought a new sensor. This thread has me dreading having to buy hubs.

 

[YukonRog]

Just saw this thread and the post on tire size being questioned. From what I've read one tire worn 1/4" smaller in diameter can throw ABS codes as well as make your Transfer Case engage all wheel drive off and on. May be worth checking. I know you've had two sets of tires on the rig with the same results, just wondering what the wear is on both. Although I'm leaning towards bad wiring on that front sensor.

 

[Doubeleive]

Very unlikely wheel or tire size would have anything to do with it unless you were running 3 different sized wheels
looks like the front left abs sensor has a broken wire or the hub is bad, swap left & right sensors and see if the problem follows
you also have a bad brake switch, which is probably related to the cruise control circuit (maybe) you def won't have any cruise control
and you might have a bad torque converter solenoid, not real big on the inner workings of the trans but that would be my first guess

 

[MassHoe04]

Very unlikely wheel or tire size would have anything to do with it unless you were running 3 different sized wheels
looks like the front left abs sensor has a broken wire or the hub is bad, swap left & right sensors and see if the problem follows
you also have a bad brake switch, which is probably related to the cruise control circuit (maybe) you def won't have any cruise control
and you might have a bad torque converter solenoid, not real big on the inner workings of the trans but that would be my first guess

Thanks for your advice! - Greatly appreciated!!

I will offer some additional information, in effort to see if anything jumps out at you...

Here is/are the weird thing(s)...

Cruise works fine. Used it all weekend on the highway. On/Off/resume/accel all work as expected and maintained speed perfectly.

Transmission shifts as expected and smoothly. Using all gears and nothing unusual.

Brake lights work and have not been flaky at all.
The ABS light is only above 50 or 55 MPH on the highway.
No ABS codes anywhere in the scanner after I cleared the C0225 Sunday night.
I have been doing in-town driving since them and no speeds over 50 around town.
No ABS light/chime activations locally. Ever. Just highway...

I cleared all those codes and scanned this morning. The same 8 codes are back plus 3 new ones... Knock Sensor Circuit Low Voltage, Knock Sensor 2 Bank 2 Low Voltage.

Still, nothing tripping CEL and main scan says no DTMs stored. These codes I see are only visible in the "Chevrolet OEM Enhanced - ECM" menu on my scanner.

Am I crazy to still lean towards possible grounding issues causing these weird codes while everything seems to be working functionally just fine?
It just doesn't seem like any of the codes listed in that sub-menu on my scanner are legitimate problems.

I'll be doing front brakes, checking some ground connections Friday, when I am off from work.
I will swap left and right ABS sensor while I am in there with the rotors off.

 

[Doubeleive]

Thanks for your advice! - Greatly appreciated!!

I will offer some additional information, in effort to see if anything jumps out at you...

Here is/are the weird thing(s)...

Cruise works fine. Used it all weekend on the highway. On/Off/resume/accel all work as expected and maintained speed perfectly.

Transmission shifts as expected and smoothly. Using all gears and nothing unusual.

Brake lights work and have not been flaky at all.
The ABS light is only above 50 or 55 MPH on the highway.
No ABS codes anywhere in the scanner after I cleared the C0225 Sunday night.
I have been doing in-town driving since them and no speeds over 50 around town.
No ABS light/chime activations locally. Ever. Just highway...

I cleared all those codes and scanned this morning. The same 8 codes are back plus 3 new ones... Knock Sensor Circuit Low Voltage, Knock Sensor 2 Bank 2 Low Voltage.

Still, nothing tripping CEL and main scan says no DTMs stored. These codes I see are only visible in the "Chevrolet OEM Enhanced - ECM" menu on my scanner.

Am I crazy to still lean towards possible grounding issues causing these weird codes while everything seems to be working functionally just fine?
It just doesn't seem like any of the codes listed in that sub-menu on my scanner are legitimate problems.

I'll be doing front brakes, checking some ground connections Friday, when I am off from work.
I will swap left and right ABS sensor while I am in there with the rotors off.

then they must be historical codes, must be things that a previous owner fixed because a bad knock sensor would def have a check engine light on
when you swap the sensor, if the code follows then it is a bad sensor if it stays on left then it'a bad hub
I am guessing it's not really a broken wire then because it wouldn't read at all and you would have trouble coming to a complete stop because the abs would be kicking in
swapping the abs sensor is simple, it's 1 bolt and a couple clips that hold the wire along the control arm and then it unclips from the harness. left & right are identical.

 

[MassHoe04]

then they must be historical codes, must be things that a previous owner fixed because a bad knock sensor would def have a check engine light on
when you swap the sensor, if the code follows then it is a bad sensor if it stays on left then it'a bad hub
I am guessing it's not really a broken wire then because it wouldn't read at all and you would have trouble coming to a complete stop because the abs would be kicking in
swapping the abs sensor is simple, it's 1 bolt and a couple clips that hold the wire along the control arm and then it unclips from the harness. left & right are identical.

On Sunday, there were 8 of those codes in the "Chevrolet OEM Enhanced - ECM" section of my scanner. I cleared them. Today, there were 11. The same 8, plus another 3. Two were related to knock sensor circuit low voltage.
They weren't in there Sunday, but now they are. I agree, there should be a CEL, if sensors were bad. Engine purrs like a kitten and no CELS or DTM codes. Feels like the system is almost making these things up. Or maybe the scanner can't really clear codes stored in that part of the computer... ?

 

[TJ Baker]

Just tossing this out here for what it's worth. The trouble with scanners is they don't always tell you the true status byte value but their intepretation. I read my codes hands-on, issuing the requests with a serial terminal so I see the actual response from the module, not some softwares translation.

First image is from SAE J 2190 describing the 8 levels of code status.

Second image is an annotated screenshot from my reading of codes from a PCM using a mode $19 request and asking for all codes with bit 5 set. May look like confusing gibberish but it isn't really all that hard to do and only requires a $15 OBD2 adapter.

Last image here is some of the basics of decoding the messages...

 

[MassHoe04]

Just tossing this out here for what it's worth. The trouble with scanners is they don't always tell you the true status byte value but their intepretation. I read my codes hands-on, issuing the requests with a serial terminal so I see the actual response from the module, not some softwares translation.

First image is from SAE J 2190 describing the 8 levels of code status.

View attachment 356231

Second image is an annotated screenshot from my reading of codes from a PCM using a mode $19 request and asking for all codes with bit 5 set. May look like confusing gibberish but it isn't really all that hard to do and only requires a $15 OBD2 adapter.

View attachment 356232

Last image here is some of the basics of decoding the messages...

View attachment 356233

Thanks! I am fairly tech. savvy, but my head was spinning a bit after seeing that. I do get your point that the scanners do a bit of interpretation and translation that may or may not be the full or true story... Thanks for the information.

 

[Walchit]

Switch those abs sensors around. I was getting an ECBM motor relay circuit code, because the new sensor I put in was shorter that the original, I had to remove a shim, and now everything seems fine.

 

[MassHoe04]

Switch those abs sensors around. I was getting an ECBM motor relay circuit code, because the new sensor I put in was shorter that the original, I had to remove a shim, and now everything seems fine.

I decided I won't bother swapping sensors. I have a new Echlin sensor waiting at NAPA for me.

 

[Walchit]

Look at it next to your old sensor, and use the shims to make sure it's the same distance from the tone ring. Then you shouldn't have to take the caliper off twice like I did, lol

 

[MassHoe04]

SOLVED!

I finally got to front rotors, pads and looking into the ABS sensor issue that was driving me bonkers on the highway... The issue I had was ABS check ran OK on start-up, no ABS lights/chimes driving anywhere around town. Only on the highway, after a couple of miles, the light/chime would come and go constantly. On my weekend commute of 30 miles each way, the chimes were driving me insane! Then they would go off and stay off, once I got off the highway and drove less than 50/55 MPH.

Potential suspect causes:
Bad wires/connections.
Bad sensor.
Bad hub.

Instead of cleaning and replacing the old sensor in the same hub or swapping positions with the problematic left sensor over to the right side to see if the issue follows or replacing the entire hub with a new one including a new sensor, I decided to try a new sensor first. Fewer steps and less chance of having to re-do hub and brake removals.

I bought NAPA brand ABS sensor (Echlin in this case) for $38. NAPA Part # UP 531158.
I got it on sale and had $5 in rewards points to use. Final total cost for the order was $28.90.

Hub was solid. It rotated easily and smoothly. It made no unusual groans or grinding noises. That was promising.

I pulled the old sensor out and inspected. There was a single shim under it, but the sensor looked like the tip was grinding into the reluctor ring in the hub. Kind of looked like the tip of the sensor was ground off and slightly curved. Maybe the last time the ABS light/chime came on, someone ordered an Amazon special or generic part that was just a hair too long. Not sure...

I sprayed down the reluctor wheel with BrakeKleen and blew it out with compressed air. That cleaned up the ring good. There was a very slight groove in the ring, probably from a sensor that was too long grinding into it... But, it didn't look too serious. I test fit the new sensor. It seemed like it made slight contact, so I re-used the single shim that was under the old sensor. Felt like it cleared perfectly. I put it in and completed the front brakes.

ABS test on start-up was OK. Things were off to a good start. No light/chime around town. Also a good sign. Real test was my usual weekend commute on the highway Saturday.

As of Sunday, I have driven 3 runs on the highway of 25 miles each. Highway aversion therapy is finally over!!! My sanity has been restored! No ABS lights or brain piercing chimes!!! I actually love driving my "new" Tahoe on the highway now. It just cruises along nice and quiet. These are fantastic vehicles and I am glad I got into one!

Thanks for all your support/advice! I managed to get off the hook pretty cheap and easy on this one. I am happy my Zurich scanner from Harbor Freight was able to narrow down the issue to the left front sensor. That saved me a lot of time trying to find the source of my problem and save me a lot of money by me not just replacing all the sensors to see what worked.

Thanks!

P.S.: Raybestos pads and rotors from our forum sponsor, RockAuto, for less than $100 shipped! Could not be beat. I normally go premium coated, but had to do a budget job this time. Similar basic pads and rotors were averaging about $200 locally.

 

[Walchit]

I'm happy for ya! I got mine for the wife/family hauler, so I feel like ABS is a necessity. I would have probably re-soldered my ABS module if I didn't buy the scanner, so I feel like it's probably paid itself off already.

 

[corvette744]

Good info guys.