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New to the site and must say it is very helpful site. I have a 1994 F-350 4X4 with a 7.3 litre diesel. My ABS light is on! I took the batteries out to clean corrosion and repaint the trays, then noticed my light on. After careful research and testing ( pulled the RABS connector behind the glove box, shorted to ground to get a code 12 ) I see where disconnecting the battery could cause the light to come on and the vehicle might have to be driven 10 miles or so for the adaptive learning process to re-learn. Well I have driven it at least 20 miles and the light is still on? I have checked the fuses. I have checked the float in the master cylinder and the level switch. Light is still on. I have noticed that when I start the engine, if I keep the brake pedal depressed, the light will never come on, but the second I release the brake pedal the light comes on. So I thought possibly the brake light switch. Tried that. Didn't work! Any ideas anyone. Your help would be greatly appreciated. Thank you in advance.
Yes, it said that by disconnecting the negative lead(s) of the battery could result in a code 12 and that it could take 10 miles or more for the adaptive learning process to clear the code. I have driven the truck at least 20 miles since I removed the batteries and the code persists. I have noticed that the ABS light will not come on when I first crank the engine "IF" I keep the brake pedal depressed. But as soon as I release the brake pedal, the light pops on. I don't know if that means anything or helps. Any ideas?
This is a puzzle. The first thing the ABS needs to activate it every time is a signal from the brake pedal so there is nothing strange happening there. Have you checked the fluid level in the resevoir? Also check the electrical connections to the master cylinder. I can`t really see how disconnecting the batteries could upset the system so I would look elsewhere. When you switch the ign. switch to "on" the ABS light should light for a few seconds and then go out. Does yours stay on?
Code 12.6 in All Data shows where a loss of battery power can turn on an ABS light and will remain on for 10 miles or more until the adaptive learning process has a chance to re-set, erase, and turn off the MIL. When the key is turn on the ABS light comes on, when the engine is started the light stays on for only a second or two then goes off ( normal ) then after a couple of seconds it will come on and stay on. I have noticed that if I depress the brake pedal while starting the engine, and keep it depressed after it has started, the light will never come on until I release the brake pedal making me think possibly brake light switch...but I have tried that. Any ideas?
Sorry I did not answer all of your question. Yes I have check the fluid level in the master cylinder. Fluid level is fine, and clean. I have also checked the float switch, and connection at the master cylinder.
All I can suggest is to check that BOTH rear stop lights are working as this can throw up an error. Also do a search for Kelsey Hayes RABS fault finding and go thru the whole system.
Both brake lights are working fine. Everything currently is pointing to the master cylinder level switch. I am going to try to jump the DG/Y wire with the T/LG wire and see if the light goes out. If it does, then it is the level switch. Thanks for your help.