Solved 99 explorer c1234

[Lee's Automotive]

Hello I have a 99 explorer 4.0 SOHC with code c1234 i have replaced the speed sensor in the rear diff and the speed sensor in the right front but the code keeps coming back with a pulsating brake pedal and ABS Light

 

[donalds]

Best way to fix this is
A $20 elm327 dongle
And forscan a free app

Then look at live data .....all 3 sensors at the same time ....

^^^ this is stuff you need to work on these trucks. Imo

 

[Lee's Automotive]

Best way to fix this is
A $20 elm327 dongle
And forscan a free app

Then look at live data .....all 3 sensors at the same time ....

^^^ this is stuff you need to work on these trucks. Imo

I've done that and it shows the speed going in and out like if i go 30 it says 30 then 20 and back and forth

 

[donalds]

Scan it at the speed that it is acting up
All sensors should read the same speed

Or throw the parts cannon at it

 

[Lee's Automotive]

Scan it at the speed that it is acting up
All sensors should read the same speed

Or throw the parts cannon at it

It happens at any speed I have already changed the sensor

 

[Mbrooks420]

Connector or wiring next.

 

[Mbrooks420]

The only other options are whatever it uses for a tone ring, or the input that reads the information as a last resort.

 

[Lee's Automotive]

The only other options are whatever it uses for a tone ring, or the input that reads the information as a last resort.

Not sure how to replace the tone ring is there any instructions?

 

[jr230]

Hello I have a 99 explorer 4.0 SOHC with code c1234 i have replaced the speed sensor in the rear diff and the speed sensor in the right front but the code keeps coming back with a pulsating brake pedal and ABS Light

i have had 3 explorers 99 the antilock failled minor accident not long after the like came on i drive it like it did not have anti never had any problem for 15 yrs. my 03 clunkers it was light on so no anti . now my 04 same thing 1 in a great while it will pulse 1 time only with fast stop not really a problem. it an old truck you could spend a lot fixing and only have it fail again . just my opinion 3 million of urban and suburban driving for living 99% without anti lock brakes

 

[Mbrooks420]

I’ve never had an issue with anti locks in my Ranger based vehicles. Not a complicated, or expensive system.

 

[J_C]

Not sure how to replace the tone ring is there any instructions?

Do you have 4WD or 2WD/RWD? With 4WD, the tone aka reluctor ring is inside the hub, not replaceable separately, but those never go bad, rather it would be the hub itself (bearings) shot so the ring is not close enough to the sensor any longer, or metallic particles from bearing wear are fouling the ring, getting between the teeth.

If you had significant corrosion on the hub where the sensor mounts, you might try cleaning that off, in case the new sensor is not close enough to the ring.

If you have RWD, the ring is on the back of the (front wheels') rotor, and you might be able to clean it off.

HOWEVER, that C1234 code is for the sensor itself not being seen by the ABS module, so if you clear the code, and next time you run the vehicle, not driving anywhere yet, then if the code comes back you know it's not the tone ring because the vehicle has no feedback about whether the tone ring is doing its job if the vehicle isn't moving.

One thing I would do is pull the connector for the ABS module and check continuity between the corresponding contacts for the right front sensor, and at the connector for that sensor. More info about possible connector pinout in this topic:

Resistance rear wheel speed sensors

What's the resistance of the rear wheel speed sensors of a 2003 Ford Explorer Sport Trac to test it with a multimeter? What is the best way to test rear wheel speed sensors and wire?

www.explorerforum.com

 

[Lee's Automotive]

Do you have 4WD or 2WD/RWD? With 4WD, the tone aka reluctor ring is inside the hub, not replaceable separately, but those never go bad, rather it would be the hub itself (bearings) shot so the ring is not close enough to the sensor any longer, or metallic particles from bearing wear are fouling the ring, getting between the teeth.

If you had significant corrosion on the hub where the sensor mounts, you might try cleaning that off, in case the new sensor is not close enough to the ring.

If you have RWD, the ring is on the back of the (front wheels') rotor, and you might be able to clean it off.

HOWEVER, that C1234 code is for the sensor itself not being seen by the ABS module, so if you clear the code, and next time you run the vehicle, not driving anywhere yet, then if the code comes back you know it's not the tone ring because the vehicle has no feedback about whether the tone ring is doing its job if the vehicle isn't moving.

One thing I would do is pull the connector for the ABS module and check continuity between the corresponding contacts for the right front sensor, and at the connector for that sensor. More info about possible connector pinout in this topic:

Resistance rear wheel speed sensors

What's the resistance of the rear wheel speed sensors of a 2003 Ford Explorer Sport Trac to test it with a multimeter? What is the best way to test rear wheel speed sensors and wire?

www.explorerforum.com

It's RWD

 

[Lee's Automotive]

Update: turned out to be bad wheel bearings that caused the light all is good now thanks everyone