ABS Sensor Diagnostic Help

Sorry that this is a cross post from the Body Mount GB thread. Just looking for help.

In the process of installing new body mounts, I broke a wire broke off at the front left ABS connector. I didn't see the bracket on the coilover support and only unfastened the ones on the UCA, which was of no help.

I disassembled the connector and soldered the wire. I'm getting a lower resistance measurement on the front left harness compared to the right side which doesn't have an error. 0.347MOhm compared to 0.366MOhm. The wheel sensor side of the connection has the mounting stud, so the vehicle side harness should not have been under any stress and gets reasonable voltage and resistance values. The CEL will not clear, so it is a consistent fault. FML.

Any ideas?

Thanks!

 

Looking at the speed sensor diagnostics here, I cannot sort out what the diagrams and symbols meaning compared to the tables.

https://www.ttguide.net/open_or_short_in_front_speed_sensor_rh_circuit_c1405_c1406_-574.html

 

Are you checking at the connector end, or at your solder repair? Check for power at the sensor wire connector from the car, should be 12v with the key on I believe.

 

Best to replace said speed sensor.

 

Thanks! I just wrapped up, but will do that in the morning.

Thanks!

I agree, but I was able to repair an ABS line in the past from a different FUBAR.

I might be a bit worried that the repaired harness is now okay but I screwed something else up at the same time?

 

I’ve broken some harnesses before. I checked for continuity at each end of the harness to find the fault, replaced the whole run of wire with whatever wire I had laying around, and then it was good to go.

I’ve also broken one off too close at the connector to solder it back together so I replaced it with this eBay harness with no issues. Sorta rambling reply but hopefully it helps.


https://www.ebay.com/itm/3923944554...X9iNZ90QPi&var=&widget_ver=artemis&media=COPY

 

Thanks!

It is funny the the left harness is twice the price as the right in my other searches.

I soldered the wire to the pin in the connector. It broke right at the crimp on the pin.

So, I can assume that impedance is not very important? I cannot measure that with my multimeter.

 

I thought you measured resistance? Resistance is basically the same thing as impedance, but impedance is used in house wiring.

I’d agree though that you most likely stretched the wire so where in the cable before it broke, it takes a lot of force to break at the pin.

 

I am not a sparky expert. Just spitballing. Hahaha!

Good point though. I will check continuity tomorrow.

 

Fuck yeah! @ktbell444 in the clutch. Got me color schematics. The ABS sensors have polarity! All good!

 

Impedance can be simply described as very similar to resistance but in the AC realm. Impedance is very relevant relevant to electronic devices as an impedance discontinuity can cause noise problems within the circuit.

 

Impedance (Z) is a combined effect of resistance and reactance (capacitance / inductance ) in ac circuits.

Ohms with a multimeter is good enough for what you are doing.
How is the shield / ground ? Wires are also twisted for noise immunity.
Maybe you stretched the wire inside the cable somewhere ?

 

Yessir. But, no snipping. Yesterday, I just stripped back a bit more insulation and soldered. Today, I just disassembled and swapped sides with @ktbell444 's info. Blue to blue on the left side.

Thanks!

For the ABS harnesses, there is no shielding or twisted pairs. There is polarity though. Thankfully that was the easy and immediate fix.

 

Thank you for the ideas!

Sorry. I missed some details in my excitement. It was the same resistance at the sensor.



The resistance in the repaired harness was 0.0ohm on both strands.

I think @EatSleepTacos is right. We could fabri-cobble a harness when in need.

 

I’ve made a harness with 14 gauge wire, CAT5 cable and 22 gauge wire and never had any issues with proper resistance. Much cheaper than replacing the whole thing if you can avoid it.

 

Agreed! Thankfully it is that simple in a pinch.

Nice move, Toyota. Hahaha!