C1236

[FordFanaticTony]

hello everyone. Have a 05 f-350 6.0 4x2 causing an intermittent C1236 and ABS light. Previous tech installed a new sensor and connector to the diff. abs sensor. I see it happen very intermittently. Takes sometimes 10 miles for it to reappear. Just wondering if anyone has seen this. Engine started making a whining fan type or belt type of noise of late. Was wondering if maybe a bad alternator can cause this. Thank you ahead of time.

[Keith Browning]

Not sure about the alternator idea...  basically the rear sensor signal is dropping out or becomes too weak. The obvious would be the sensor which has already been eliminated for you but just make sure the mounting area is not rusted up jacking the sensor away from the tone ting in the rear. It would be in your best interest to measure the resistance in the circuits from the ABS module and wiggle test the harness. Also look closely at the harness for signs that someone else has poked holes in the wires trying to diagnose something which may lead to corrosion and a failing circuit. I cant tell you how many times I have seen that over the years. .

[FordFanaticTony]

Thank you Keith I will look at the mounting surface and circuits.

[Brad Clayton]

On 8/29/2019 at 7:40 AM, Keith Browning said:

Also look closely at the harness for signs that someone else has poked holes in the wires trying to diagnose something which may lead to corrosion and a failing circuit. I cant tell you how many times I have seen that over the years. .

I find it amazing that this has become a more normal diagnostic procedure as of late. I shake my head and roll my eyes and wonder of the stock in liquid electrical tape has risen.