ABS Light and Brake Light when moving

Please help. I've got a 1999 Silverado Z71 5.3L. Recently the ABS light came on as well as the Emergency brake light. The funny thing is they only turn on when i am moving forward and they both come on at the same time. Does anyone have any ideas? Please help.

Sounds like you may have a bad speed sensor. I have a similar problem, but mine comes on sitting in park. I just bought a OTC scanner and I pulled like 10 codes just for the ABS. I am just hoping mine is a wire cut or worn. Good luck with yours.

Mine started doing this before my ABS pump went out. This was one of the problems 99s had(the abs pump). Don't know if it applies in your case, but just be ready for it anyway. I got out of my truck one day and heard the pump whining under the truck. The truck was off and the key was out. I had to take out the fuse for the ABS. I went to the dealer to see what this pump cost, and he quoted me a price of about $700. Obviously, I told him he could keep it, and I've been driving without it for about 50,000 miles. The only downfall is that my ABS and brake light stays on all the time. My truck still brakes perfectly, I just don't have ABS. It's actually more fun to have the ABS off. I can lock it up and play alittle more than I used to. I think I'm just gonna take out the bulbs that light up the ABS and brakes and not even worry about it.

You were right "Slowprocess" Turns out it was the ABS pump or somethin. My truck has bout 60,000 on it. They pulled some EBCM code. THe quoted me $800 for the part and $100 for labor. I'm more than slightly miffed. I called Chevy and complained and asked them to assist with paying for this. They have yet to get back to me. I figure, the more people whine about this, the more likely they are to recall it or somethin.
This truck and i have been through a lot together. Heck, my first son was conceived and born in this truck. I'd hate to let it go now.

If your amber ABS lamp and the red "parking brake" warning lamp illuminate together without any prior pump constantly running problem; the pump motor wires are most likely broken.

The heat shrink tubing that seals the red/black power leads to the motor may have allowed water to enter. The copper conductor turns into a powdery green copper oxide over time due to electrolysis as a small current is applied to the motor all times (even when vehicle is off). The wires will look perfectly intact on the outside even though the copper conductor has been destroyed. The associated error codes will either be C0267 or C0268.

Initial problems will be an intermittent amber ABS and red BRAKE lamp illuminating simultaneously. Over time, the lamps will stay on constantly. In any of the circumstances, you have lost your ABS at all times... even when the lamps are off during the intermittent stage of the system failure.

Dealer specifies pump assembly must be replaced. Not necessary.

The wires can be resoldered to the motor terminal block and resealed with new heat shrink tubing and sensor safe silicone. Do not remove the motor from the pump housing as it is difficult to align the eccentric cam on the motor shaft with the pump mechanism.

This is a common problem that can be solved by resoldering the pump power leads. If the pump runs all the time and the red "BRAKE" lamp has illuminated after pulling the ABS fuse or unplugging the motor; the EBCM (ABS control module) will have to be rebuilt. This can be done for $100.

Both pump motor failure and EBCM failure can be repaired without costly replacement.

Apparently this is a common problem. I had a wierd coincidence when my failure occured and I am wondering if anyone else has had a similar occurence. Apparently, the rear wheel speed sensor is mounted in the differential. 15-minutes before my failure, I had the rear differential fluid inspected at a lube shop. I'm wondering if a too low or too high fluid level could cause a faulty sensor reading, mistrigger the EBCM, and damage the control module. The symptoms are a continuous running hydraulic motor (fuse pulled). If the electrical design is faulty and the EBCM get's damaged by a bad sensor reading, we can probably have a recall issued.

Apparently this is a common problem. I had a wierd coincidence when my failure occured and I am wondering if anyone else has had a similar occurence. Apparently, the rear wheel speed sensor is mounted in the differential. 15-minutes before my failure, I had the rear differential fluid inspected at a lube shop. I'm wondering if a too low or too high fluid level could cause a faulty sensor reading, mistrigger the EBCM, and damage the control module. The symptoms are a continuous running hydraulic motor (fuse pulled). If the electrical design is faulty and the EBCM get's damaged by a bad sensor reading, we can probably have a recall issued.

99Chevy,

If the pump is "stuck on", the problem is a failure in the electronic control module (EBCM). The EBCM will have to be replaced or repaired. The EBCM can be repaired for $100 with new parts that will not fail again. Go to www.circuitsolutions.info and click on the ABS icon for details regarding the repair.

It is possible for the rear sensor in the pumpkin (rear differential) to produce a weak output due to metal particle build-up. The sensor has a permanent magnet inside, so it will attract the metal filings from normal diff wear. However, this is not the cause of the pump running constantly problem. The rear wheel speed sensor in the rear diff does not go to the ABS module. Instead it is wired directly into the engine/drivetrain computer so it knows vehicle speed. A wire comes back out of the engine control computer with the analog amplified rear wheel sensor info. It is then split to provide info for the speedo, cruise control, ATC (auto transfer case) and ABS system.

If the rear wheel sensor is the culprit, your speedometer will not work, transmission will not shift properly and cruise control will be affected.

The pump running constantly is from a burned out motor control chip inside of the EBCM. The only time the EBCM will turn on the red "brake" lamp with the amber "ABS" lamp is when the pump motor control circuit has lost power... that is if the pump ABS fuse (60amp) has been pulled, power or ground wire to the pump wire cut or if the wires to the motor have corroded and separated.

There are no other software "flags" in the EBCM that will set the red "brake" lamp together with the amber "ABS" lamp. Only the open pump motor circuit.

Every time the truck is started, the computer in the EBCM performs many tests.. one of which is a spinup test of the pump motor. The motor control chip has a finite number of "motor run" operations before burning out. The average vehicle mileage is 40-50K miles when failure occurs. However, some vehicles have experienced pump failure with as few as 16,000 miles (lots of short trips between starts) to about 80,000+ (many highway miles between starts).

If your amber ABS lamp and the red "parking brake" warning lamp illuminate together without any prior pump constantly running problem; the pump motor wires are most likely broken.

The heat shrink tubing that seals the red/black power leads to the motor may have allowed water to enter. The copper conductor turns into a powdery green copper oxide over time due to electrolysis as a small current is applied to the motor all times (even when vehicle is off). The wires will look perfectly intact on the outside even though the copper conductor has been destroyed. The associated error codes will either be C0267 or C0268.

Initial problems will be an intermittent amber ABS and red BRAKE lamp illuminating simultaneously. Over time, the lamps will stay on constantly. In any of the circumstances, you have lost your ABS at all times... even when the lamps are off during the intermittent stage of the system failure.

Dealer specifies pump assembly must be replaced. Not necessary.

The wires can be resoldered to the motor terminal block and resealed with new heat shrink tubing and sensor safe silicone. Do not remove the motor from the pump housing as it is difficult to align the eccentric cam on the motor shaft with the pump mechanism.

This is a common problem that can be solved by resoldering the pump power leads. If the pump runs all the time and the red "BRAKE" lamp has illuminated after pulling the ABS fuse or unplugging the motor; the EBCM (ABS control module) will have to be rebuilt. This can be done for $100.

Both pump motor failure and EBCM failure can be repaired without costly replacement.


Well I guess it is my turn to trouble shoot this problem. 99 silerado with 94,000 miles and as I was comming to work today the ABS and Parking brake lights came and stayed on. :uhoh: I remembered reading this forum a while back and found it again to refreash my memory. I guess I will check My fuses and wiring to the pump before I let the dealer look at it. The brakes seem to work fine for now. Will try and get the ABS pump powered up and cross my fingers.

99 Silverado with 33K miles. ABS & Brake light came on and pump runs continuously. Brought to national chain to repair, they told me the aftermarket radio (tuned to AM band)was somehow interfering with ABS possibly wired into ABS system. Charged me $51 for annalysis and said it was beyond them. Told mechanic AM radio picks up noise of any motor and the only thing wierd lately was that I went through very deep puddles 2 weeks prior. Fortunately I went to this forum before going to dealership. Thank you.

I know this is an old topic, but my '01 Silverado Z71 has the same prob I think. At first the ABS light came on, then a week or so later, the "parking" brake light came on. I checked the owner's manual and it said if both come on your brake system needs service.BTW, I think the "parking" brake lamp is for your regular brakes also...I think. That's what it insinuated in the manual anyway. I have 71,000 miles. Maybe one of those touchless car washes got water where it shouldn't have? It sprays under the truck as you drive in. I was hoping Gavin Curtis might still be around to help. I just got medically discharged from the Air Force and I'm broke. I think I may be able to fix it myself with some instruction. Help please!! I worry about safety with my kids in the truck. Thanks for any help.