ABS light keeps coming on?

It sounds like the ABS hub is defective. Here are two videos the first one show how to do the job correctly the other is to scan the ABS to confirm the failure.

https://youtu.be/ZgiPRG6jffc

and

https://youtu.be/rTtAnsOlZU4

Please run down these guides and report back.

The ABS light comes on once in a while. When you hit a bump or turn. They activate sometimes when braking for no reason.

good evening.

The most common issue with this activation is dirty sensor mountings. it changes the air gap to the tone ring and the ABS comes on braking especially when you are coming to a stop.

I would remove the sensors, clean the mounting and the sensor and reinstall. then road test it to verify the repair.

Roy

When driving the brakes work fine but it feel like they let off pressure when when they are applied. When i first noticed the problem you had to slam on the breaks to engage them but after bleeding the brakes it has helped some. The only code i can find with the OBD II is C0222. The is nothing in the cluster message center. The only sign is the ABS light stays on.

measure the resistance at the wheel speed sensor,should be between 700 and 10,000 ohms.if its higher or lower than spec replace the wheel speed sensor.

Warning comes up in message center. I have checked fluid, pad thickness, both are fine up front. The front left caliper does seem to rub a bit but not enough to stop from turning. Doesn't pull either way. Got an idea of where I might need focus on?

Have you scanned the computer to see if there are any trouble codes? It may deal with an ABS sensor. This video will help

https://youtu.be/rTtAnsOlZU4

and

https://youtu.be/Pb6nXV-iamI

Please let us know what you find. We are interested to see what it is.

Yeas I have a scanner, nothing on the abs. I havent had the ABS problems son people speak of online.

Yes I have a scanner and nothing on the abs system. I haven't had the ABS problems some people have spoke of online.

That makes it tough. Since the brakes are good, there are no ABS codes, and the fluid is full, you need to start checking wiring in the system.

NOTE: I assume this isn't a parking brake light, correct?

Na, it shows in the message center. And that damn buzzer goes off 15 or 20 times.

I recently had the ABS and brake lights pop up. Noticed while driving a sound coming from underneath. When I got home, I turned the car off, and the ABS pump was still running. Did some research and saw it was most likely the ABS control module.

Went ahead and replaced the control module, and also the 60A fuse in the electrical center. It is still doing the same thing. I am driving now by just pulling the fuse and running without ABS.

I was thinking it may be a speed sensor, but my cruise control works fine. Any ideas on what to try next?

Good afternoon,

Okay, there is a fault code stored in the system. I need that code to narrow the area of failure for you.

https://www.2carpros.com/articles/abs-warning-light-on-easy-repair-guide

Did you have the replacement module flashed or programmed to the cars VIN number? If you did not, it will not work.

https://www.2carpros.com/articles/how-to-replace-a-abs-controller

Speed sensors are the most common issue but needs to be confirmed.

https://www.2carpros.com/articles/abs-wheel-speed-sensor-test

https://www.2carpros.com/articles/how-to-replace-an-abs-wheel-speed-sensor

Roy

I've gone to several places, and nobody has a scanner that picks up ABS codes. Found a guy and going after work today. Hopefully he will be able to pick up some codes and I will share.

I did not have it flashed, I didn't think a 2001 required that. I will need to check on that also.

I should have more info tonight, and will update.

Okay, sounds good.

Replacing an ABS module always requires programming to the VIN or it will not work.

Did you put a new or used module on the car?

Let me know the codes when you get them

Roy

Okay, here are the scans. Guy didn’t know what they meant, so hopefully you do!!

Current Code:
C0265: EBCM Motor Relay Circuit

History Codes:
C0267: Pump Motor Circuit Open
C0265: Same Above
C0298: Power-train Control Fault

Oh, and I put in a “re-manufactured” module in from Autozone.

Okay, I attached the description of the code and the flow chart for finding the failure. In most cases, it is the module itself.

The 298 is for the flashing. The PCM is not communicating with the module because of a VIN mismatch.

I also attached a wiring diagram for you to verify power to the module.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

https://www.2carpros.com/articles/how-to-check-wiring

I would definitely have the module programmed by someone who has the scan tool for performing this.

Roy

Circuit Description
The ABS relay supplies battery voltage to six valve solenoids (RF dump/isolation, LF dump/isolation, and rear dump/isolation). The EBCM microprocessor applies the grounds needed to activate each solenoid. The low side of each solenoid coil has a feedback circuit to the EBCM microprocessor. When a solenoid is commanded OFF, the feedback voltage is high. When a solenoid is commanded ON, the feedback voltage is low.

Conditions for Running the DTC
The ignition is ON.
The vehicle speed is greater than 6 km/h (4 mph).

Conditions for Setting the DTC
The EBCM detects an internal malfunction.

Action Taken When the DTC Sets
C0265
If equipped, the following actions occur:
The EBCM disables the DRP/ABS.
The ABS indicator turns ON.
The brake warning indicator turns ON.

C0266
If equipped, the following actions occur:
The EBCM disables the ABS.
The ABS indicator turns ON.

Conditions for Clearing the DTC
The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.

Diagnostic Aids

Important: Whenever the EBCM is replaced for DTC C0265 or C0266, the ABS pump motor and motor circuitry must be tested for the proper resistance. Refer to steps 7 and 8 in the diagnostic table below for testing procedures and resistance values.

C0265
Thoroughly inspect connections and circuitry that may cause an intermittent malfunction.

C0266
Replace the EBCM if DTC C0266 continues to set intermittently.


Test Description
The numbers below refer to the step numbers on the diagnostic table.
4. This step tests if the battery positive voltage circuit can supply adequate power to the system relay.
7. A shorted ABS pump motor or shorted motor circuitry may damage the contacts within the system relay. Follow this step to prevent damage to a replacement EBCM.

Do you think reprogramming may resolve the issue fully, or do you think there is another wiring issue as well that you listed? Seems odd that the control module and wiring would go bad at the same time.

I think I know a guy who can reprogram, so I’ll call him tomorrow. After that it looks like an electrical wiring problem maybe.

I appreciate all the help. I’ll update you tomorrow on what I find out.

It may but if you know someone , get it done.

Then we can proceed with other checks.

You are welcome.

Roy

Sometime when i start the Tahoe and back out of the driveway the ABS light will be on. The tranny will not shift out of 1st gear while this light is on. The speedometer is at 0 also.
Any info on how this problem needs to be addressed and maybe a diagram on where the problem is.
Thanks in advance Nick

Hi there,

This may be a faulty speed sensor, a scan would normally show this as a fault code, start here.

mark (mhpautos)

Thank you sir. Is this something that autozone can pinpoint or will their scanner just give me a general problem area.

I was reading a little bit a few minutes ago and some people are saying that the speed sensor connectors can get metal shavings in them from the brake dust and cause the sensors not to read right. Im gonna go try and bleed the brakes one day this week and im gonna take a look at the connections also. Im looking for an answer to the topic below mine about brakes being bled also. The wife says the brake pedal has too much travel. Im used to it so it doesnt bother me.

Often the quality of the scanner is the limiting factor, cheaper scanners wont read all codes, so a good quality scanner should pin point he actual fault, bleeding the brakes and flushing all the old brake fluid is a good move, this should be done periodical as brake fluid is hygroscopic, that is it does attract moisture, which will boil and cause soft brakes as well as cause rust problems, i am working through another post with exactly this problem now, good luck with yours, thank you for using 2carpros, your feed back is always welcome.

mark (mhpautos)

What boggles my mind is why the tranny stays in 1st gear and wont come out until the light is off. I could understand the speedo and light issue but the tranny has me wondering.

Sometime (not often at all) when i start to come to a stop at a low speed i can feel some sort of feeling in the brake pedal and the speedo will go to 0 and the tahoe will be hard to stop. This is maybe going less than 10mph. It is a weird feeling and very hard to explain what it feels like. its almost like their may be an air pocket in the line but i dont think that is the case at all.

You may have a separate issue here, but the scan should show up any electrical fault in the transmission as well, i would concentrate on one problem at a time, get that sorted and move on to the next issue.

mark (mhpautos)

I went to Autozone today for the heck of it just to see what kind of codes it was showing. No shops were open on sundays. The check engine light has been on for a couple of years. The code that was read was p0430

Will it just show a speed sensor code when it acts up or will it have it in there from previos occurances from when it has happened.

P0430 Catalyst System Efficiency Below Threshold (Bank 2)

Well that code is a red herring, nothing to do with any of the problems that you are experiencing, it may well be a old code with no relevance, i do feel that now it will require a hands on approach, there is a limited amount that i can do from afar, have the codes cleared, bleed the brakes, if the brakes have not been bleed in some time, there may be muck in the ABS distributor head and the valving may be a bit sticky, this will not hurt at all.

mark

Im gonna take it tomorrow and get the tranny fluid flushed out and replaced. I went fishing this morning and doing down the road about a mile from the house the ABS light came on. Speedometer went to 0, when i press the gas it is like it is in neutral. It finally slowed down enough and it was like it was in 1st gear. I could manually put it in 2nd and it would go fine. When i would try for 3rd gear nothing was there. Same way in "D". After a minute or two of dealing with it everything was fine. Fished til lunch time and loaded the boat on the trailer and went back home. No issues what so ever since this morning.
I just dont understand. Could it be a sensor on the tranny?

I went to autozone to get some stuff and talked to a guy there that has a suburban to see if he has had any issues like me. I descibed the issue and he said he thinks it would be the speed sensor on the side of the tranny or transfer case. Does anyone have a diagram or picture of where this thing is located. Is this something i could do or should i take it to a shop that has a lift.

the abs light has recently came on. I replaced both front hubs 5 months ago to fix speed sensor problems. What could be problem for light coming on now?

the abs light will come on for many reasons the sensor in one of the wheels could be bad or a fuse could be blown, you could be low on brake fluid, a wheel may be locking up, etc. i would start small with checking fluid levels and fuses also is check engine light on?

Hello, I'm Danny.

Having the ABS light on means there is some type of fault code stored in your vehicle's computer. The best thing to do is have a CAN performed to check all the systems on your vehicle. Here is a tutorial showing what is involved for a CAN scan:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is a you You Tube tutorial from our site showing how to check ABS codes:

https://youtu.be/rTtAnsOlZU4

Hope this helps and thanks for using 2CarPros.