TXsilverado

iTrader: (19)

speed sensors can do it too, but ABS module is alot more common. it's a sucky problem to have lol.

GNXClone

iTrader: (7)

Both of my lights were on when I bought my truck ('99 RCSB Sierra with 195k miles). I figured it was going to be a bad wheel sensor, and would just live with it for awhile.

One day when I was under the truck changing the trans fluid, I found the ABS motor power connector was unplugged, so I plugged it back in. After that, the ABS/Brake lights would only come on intermittently, maybe 50% of the time. Sometimes when I started the engine they would stay on, and sometimes only after I started rolling (about 4MPH), other times they would stay off. As time went on, they started coming on more frequently until they were on all the time again. So I unplugged and replugged the same connector and they went out for a few days...then eventually came back on.

At this point I read the codes and had:

[Brake] C0245 - Wheel Speed Sensor Frequency Error (SES) (Pending) (History) (Current)
[Brake] C0241 - EBCM Control Valve Circuit (SES) (Pending) (History) (Current)
[Brake] C0242 - (SES) (Pending) (History) (Current)
[Brake] C0246 - (SES) (Pending) (History) (Current)
[Brake] C0251 - (SES) (Pending) (History) (Current)
[Brake] C0252 - (SES) (Pending) (History) (Current)
[Brake] C0267 - or C0268 Pump Motor Circuit Open/Shorted (History)
[Brake] C0226 - LF Wheel Speed Signal Missing (History)
[Brake] C0265 - or C0266 EBCM Relay Circuit (History)
[Brake] C0268 - (History)

Everything I read online told me I needed to send my EBCM off for repair. But since the problem seemed to go away when I messed with that one connector, I decided to disassemble the connector (the one with only two thick wires) and clean the contacts really well. I also *slightly* bent the tabs on the EBCM side of the junction to apply more pressure to the contacts.

After doing this, my ABS and brake lights have never come back on.

Mine is probably a rare case, but worth checking as the fix only costs a bit of time. I was all set to send my EBCM off to ModuleMasters. Glad I took the time to check and clean the connections.

charcold-bowtie

iTrader: (10)

Bumping this (back) up. I am having a really hard time bleeding anything from the brakes on a 2000 4x4 rcsb silvy. Getting a c0267 code and the two brake light warning. I am gettin 12 volts at the ABS module/ pump side. Any chance this could have anything to do with it? ive taken the bleeder out, pulled vacuum, pressed the pedal, keyon/off, engine running etc. Just changed all the factory lines out with nnew lines as I had one leaking. No obvious leaks right now. I cant get any fluid out of any bleeders, even with them removed. The pedal actually feels pretty good, havent put it in gear or under any load tho. I also did bleed the master cylinder on the bench.

TIA for an advice.