Help!!!! Rear Speed Sensor "open"

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usocazy

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2004
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Hemi 5.7l
Folks - I have multiple threads about my ABS module and wiring harness having so much corrosion that I needed to replace both.

I had a jack load of ABS faults and the brake light stayed illuminated.

Long story short - I cut off one of the connectors to the ABS module that had a tremendous amount corrosion and spliced in a new connector. Replaced the ABS module from a salvaged 04 Ram 2500 (know good part).

Both ABS and brake light remain lit even after replacing the rear speed sensor and clearing the fault with my ABS scanner.

Scanner reads "rear sensor / open".

Any ideas how I can check for this fault? Seems like there's a ghost in the machine I'm chasing. So frustrating!

Other threads I posted - many with pics of what I replaced:
http://www.ramforum.com/f52/help_multimeter-65770/
http://www.ramforum.com/f52/help_testing_wiring_connection-65296/
http://www.ramforum.com/f52/does_anybody_have_abs_module_wiring_diagram-64835/
http://www.ramforum.com/f45/abs_brake_light-62750/
http://www.ramforum.com/f45/need_help_abs_codes-62027/
http://www.ramforum.com/f59/do_all_3rd_gens_have_4_wheel_abs_advice_needed-62295/
 

hotkarl

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Check the wiring to the speed sensor. Actually you should probably check all the wiring. These trucks are known for brittle wiring. Check all the connector plugs. Sounds like you're just overlooking something silly like that.
 
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usocazy

usocazy

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Hey hotkarl, are you saying the wiring coming off of the sensor that goes back up into the wiring harness?

Do you know if this fault will keep both the ABS and brake light on? ABS light I understand but the brake light too? Or do all ABS faults result in a constant brake light?

Thanks.


Sent from San Antonio, Texas
 
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usocazy

usocazy

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This is a long running error for me.

Latest update is that I had a general mechanic that's handy with a multimeter take a look at my ABS module replacement and wiring job. I also had him test the rear speed sensor that I bought new and replaced. Everything tested good from the sensor back to the ABS module. Seeing that the only fault that appears is "rear speed open" in the ABS scanner (pops up immediately after clearing the code without moving the truck) and all other codes are cleared, he recommended getting the ABS module flashed. Said this was a common problem with Dodge/Chrysler vehicles - can't plug and play electronic parts.

So then I take it to the dealership to get the airbag recall stuff worked on and explain what I've done to the ABS module and wiring and need it flashed. Of course professional mechanics don't like to be told what needs to be done without checking themselves so he tells me that it's $129 to flash the ABS module but that's no guarantee that it will fix the problem.

At this point I'm at the dealerships mercy and fear that they'll come back with "well, your ABS module is bad and a new one is $1000 guaranteed for 2 years". Can't drive without ABS as I've had several "panic stops" and the truck went crazy sliding each time.

Truck goes in this Thursday. I'll update on what happens.


Sent from San Antonio, Texas
 
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usocazy

usocazy

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Final update.

Dealership flashed the ABS module and that had no effect.

Once we wired in the new connector my son, who's red/green colorblind, and I had one of the green/white wires crossed. Dealership fixed that and I was on my way. Of course the rear speed sensor, that I just replaced, wasn't seating properly (says the dealership) so they replaced that too. Paid over $350 but all is well now.


Sent from San Antonio, Texas
 

stickpony

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Final update.

Dealership flashed the ABS module and that had no effect.

Once we wired in the new connector my son, who's red/green colorblind, and I had one of the green/white wires crossed. Dealership fixed that and I was on my way. Of course the rear speed sensor, that I just replaced, wasn't seating properly (says the dealership) so they replaced that too. Paid over $350 but all is well now.


Sent from San Antonio, Texas

Where are he speed sensor and abs module located? I just bought a high miles Ram, and I have the same issues...


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usocazy

usocazy

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Where are he speed sensor and abs module located? I just bought a high miles Ram, and I have the same issues...


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Speed sensors are plugged into the rotor area of the wheel hub. ABS module should be located on the driver side of the firewall. At least that’s where it is on my 2004 Ram.

Good luck.


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