RABS Code 11
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RABS Code 11
I pulled this code the other day from my RABS and the Chilton manual said I should see no voltage with brake pedal not pressed and < 9 v when pressed. I get very little voltage, 360 mv, with brake not pressed but get 12v when it is pressed.
The book said to replace the brake switch and I did this but I don't see how it could be the problem, it doesn't have any resistors in it, just contacts. I see 12v going into that switch so the 12v is passed along when the brake is pressed.
I'd like to research where this 12v comes from. Well, I THINK it comes from pin 2 on my PCM but I can't find much info on that.
Looking for resources.
thanks.
The book said to replace the brake switch and I did this but I don't see how it could be the problem, it doesn't have any resistors in it, just contacts. I see 12v going into that switch so the 12v is passed along when the brake is pressed.
I'd like to research where this 12v comes from. Well, I THINK it comes from pin 2 on my PCM but I can't find much info on that.
Looking for resources.
thanks.
Fleet Owner
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From: Kentucky
+12V comes from the brake lamp circuit:
courtesy of Steve83
My Ford Service Manual show this if the voltage is above ~9V w/brake pedal pressed:
Voltage is 9VDC or more: Check Four-Way Flasher and Directional wiring. This condition could create feedback through the stop lamp circuit.
courtesy of Steve83
My Ford Service Manual show this if the voltage is above ~9V w/brake pedal pressed:
Voltage is 9VDC or more: Check Four-Way Flasher and Directional wiring. This condition could create feedback through the stop lamp circuit.
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What if the length of brake lines was increased in the front causing more volume needed to fill the lines. I'm about 99% sure I bled out the air but would extra length in the lines mess up the pressure in any way? I know the RABS senses the line pressure and adjusts accordingly.
I also see in the pic you provided a label that says 'to parking brake switch and low vacuum switch' Well I know I have low vacuum, you commented on my other thread, could this be a cause?
I also see in the pic you provided a label that says 'to parking brake switch and low vacuum switch' Well I know I have low vacuum, you commented on my other thread, could this be a cause?
Last edited by RIKIL; Mar 8, 2013 at 10:08 AM. Reason: cuz
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If one of your brake lights is burnt out, or you've replaced them with lower wattage bulbs or LEDs, it could cause the high voltage on that line when you hit the brake pedal.
I'd also check for bad grounds and chafing wires near the taillights and behind them. Remove the bulbs, clean the sockets, check for corrosion, etc...I'd especially check the 3rd brake light on the cab, as they are known for water intrusion issues.
I'd also check for bad grounds and chafing wires near the taillights and behind them. Remove the bulbs, clean the sockets, check for corrosion, etc...I'd especially check the 3rd brake light on the cab, as they are known for water intrusion issues.
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Code 11 ECU. Failure is for ABS, I have RABS. This code 11 only comes on above 35 MPH, which is what the Chiton manual also says
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Fleet Owner
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From: Kentucky
What if the length of brake lines was increased in the front causing more volume needed to fill the lines. I'm about 99% sure I bled out the air but would extra length in the lines mess up the pressure in any way? I know the RABS senses the line pressure and adjusts accordingly.
I also see in the pic you provided a label that says 'to parking brake switch and low vacuum switch' Well I know I have low vacuum, you commented on my other thread, could this be a cause?
I also see in the pic you provided a label that says 'to parking brake switch and low vacuum switch' Well I know I have low vacuum, you commented on my other thread, could this be a cause?
The reference to Low Vacuum Switch is for diesel trucks only.
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Fleet Owner
Joined: Oct 2005
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From: Kentucky
If one of your brake lights is burnt out, or you've replaced them with lower wattage bulbs or LEDs, it could cause the high voltage on that line when you hit the brake pedal.
I'd also check for bad grounds and chafing wires near the taillights and behind them. Remove the bulbs, clean the sockets, check for corrosion, etc...I'd especially check the 3rd brake light on the cab, as they are known for water intrusion issues.
I'd also check for bad grounds and chafing wires near the taillights and behind them. Remove the bulbs, clean the sockets, check for corrosion, etc...I'd especially check the 3rd brake light on the cab, as they are known for water intrusion issues.
I have seen many different symptoms on these trucks when someone swaps in LED replacement lamps. First time I have heard of a RABS Code 11 caused by it, but anything is possible.
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This is just a signal wire we are talking about, right? I know it doesn't power the RABS because it would only go on when the brake is pressed (absurd) but does it provide power to a solenoid or anything down the line? I'm wondering if I can put some resistors on it to bring down the voltage, if voltage is all that's needed I should be fine in doing this.
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The ABS light only comes on above 35 MPH but not necessarily if I press the brake pedal above 35. Makes me think a resistor won't work and I need a valve as you suggest. Are you talking about a valve inside the ABS unit?
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I got the output voltage to 4v by splicing the green wire (this is the wire indicated in the Chilton manual that should have < 9v with brake pedal pressed) and using some resistors. Will have to see how this behaves with the system...