Added 4.10's, now rear speed sensor won't read??? 2005

Mountainman · **Posted:** Tue Sep 13, 2022 9:46 pm

Anyone had a problem with 4.10's and the speed sensor not reading? I have 1mm between the new sensor (and used) and good alignment/engagement with the sensor. I measured 11.6 volts with the ignition on, but not running today. Ran new wires to it a few years ago, all connections soldered.
Typical symptoms, brake and abs dash lights, and odometer doesn't count.
Thanks for any insight.

WWDiesel · **Posted:** Tue Sep 13, 2022 11:46 pm

Mountainman wrote:

Anyone had a problem with 4.10's and the speed sensor not reading? I have 1mm between the new sensor (and used) and good alignment/engagement with the sensor. I measured 11.6 volts with the ignition on, but not running today. Ran new wires to it a few years ago, all connections soldered.
Typical symptoms, brake and abs dash lights, and odometer doesn't count.
Thanks for any insight.

Maybe a bad sensor?

Quote:

OPERATION
The sensors convert wheel speed into a small digital signal. The CAB sends 12 volts to the sensors. The sensor has an internal magneto resistance bridge that alters the voltage and amperage of the signal circuit. This voltage and amperage is changed by magnetic induction when the toothed tone wheel passes the wheel speed sensor. This digital signal is sent to the CAB. The CAB measures the voltage and amperage of the digital signal for each wheel.
(CAB=Controller antilock brake)

Mountainman · **Posted:** Wed Sep 14, 2022 1:24 am

More details: it went to the shop with the sensor working, and left with the no read condition. I installed a new mopar sensor today, no change. I need to dig through the service manual and see if they have a spec for the gap. But, same tone ring, same gap. I'm lost

WWDiesel · **Posted:** Wed Sep 14, 2022 2:02 am

I looked, did not find spec for gap.
Try hooking a volt meter in series with one of the connections to the sensor, spin the rear wheels up and see if the voltage signal fluctuates any.
This would test the sensor function. Now if you had a scope, that would be even better.
This circuit has THREE connectors on it, C100, C201, & C307. I would check all three of them and makes sure the signal is passing through them.
Since it has two wires, one is 12v feed and you said it is good, it could be a lost connection on the other wire going back to the ABS module where the signal is broke out via the PCI bus to feed the speed signal to the Body Control module that produces the speed signals for the speedometer, etc...
The ABS module has one ground circuit. It has two 12v feeds via fuses 4 & 25 in the Power Distribution center, make sure both of them are good.

Just a left field thought, is the speed sensor pickup setting dead over the tooth ring? Did changing the carrier move the tooth ring over?
Does the 410 ring gear require a different thickness tone ring?

Mountainman · **Posted:** Fri Sep 16, 2022 12:56 am

WWDiesel wrote:

I looked, did not find spec for gap.
Try hooking a volt meter in series with one of the connections to the sensor, spin the rear wheels up and see if the voltage signal fluctuates any.
This would test the sensor function. Now if you had a scope, that would be even better.
This circuit has THREE connectors on it, C100, C201, & C307. I would check all three of them and makes sure the signal is passing through them.
Since it has two wires, one is 12v feed and you said it is good, it could be a lost connection on the other wire going back to the ABS module where the signal is broke out via the PCI bus to feed the speed signal to the Body Control module that produces the speed signals for the speedometer, etc...
The ABS module has one ground circuit. It has two 12v feeds via fuses 4 & 25 in the Power Distribution center, make sure both of them are good.

Just a left field thought, is the speed sensor pickup setting dead over the tooth ring? Did changing the carrier move the tooth ring over?
Does the 410 ring gear require a different thickness tone ring?

Thanks WW! the ring isn't dead center, but it is completely engaged, or the sensor is above 100% of the tone ring. I'll give the tires a spin and see what I can see. I have a scope, just haven't used one in 20 years. Sounds like I need to give it a go for an accurate reading of what is going on.

Added 4.10's, now rear speed sensor won't read??? 2005

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