96 chevy ABS update

Not unless there is a malfunction in the ABS.

Not really. it you make it more complicated than it is, I guess so.

2 for the RF, 2 for the LF and 2 for the rear going to the VCM. Six measly wires...

Now on the front sensors, if one was to locate the sensors and follow to where they plug into the harness, he would see what color the insulation on the wire is, he could then go to the BPMV connector, locate the corresponding colored wires and begin testing. You have my personal guarantee that there are no duplicate wire colors at the BPMV that would make this anything less than foolproof. Since the rear sensor wires go to the VCM and there are more wires to deal with I'll tell you straight out that the rear sensor wires go to cavities 29 and 30 of connector #1. Now you're probably asking yourself; how can I tell connector one from connectors two, three, four and five? Again, you will use your powers of observation until you find wire colors that match the harness to the rear sensor in cavities numbered 29 and 30. Again, there are no duplicate wire colors of those two colors in any other connector to the VCM in cavities 29 and 30.

Just a little 'and-or-nor' logic.

Reply to
aarcuda69062
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Thanks so much! That helps alot. One thing, on this truck is the rear wheel sensor in the tranmission or the tranfer case? (I have seen posted both).

So I would look for the color of the wires plugging into that snesor and look for those same colors in the ABS module right? I am assumign it will read ok testing those wires disconntected from the ABS module rather than backprobing them?

By cavities "29 and 30" are these numbered spots in the ABS electrical connector?

I appreciate it. What you have said makes sense.

Reply to
stryped

It's in the transmission is it is a two wheel drive, in the transfer case if it is a four wheel drive. The ABS rear wheel speed sensor also serves as the vehicle speed sensor, if you think about it, the transfer case [can] serve as an underdrive so in order to maintain an accurate speedometer, the vehicle speed sensor (AKA ABS rear speed sensor) has to be at the rear of the transfer case reading directly off of the output shaft. It's just common sense.

For the front sensors, yes. They are wired directly to the ABS module.

You are trying to determine two things;

1) The continuity of the circuit because of the "open" codes. 2) Whether the tone ring is functional because of the "missing" codes.

One last time... 29 and 30 are at the VCM IOWs the engine computer. The rear wheel speed sensor AKA vehicle speed sensor connects DIRECTLY to the VCM, NOT the ABS controller.

Does the dashboard mounted speedometer work? If it does, then the problem (with the rear sensor codes) probably lies between the VCM and the ABS module.

If you don't mind me asking; what do (or did) you do for a living?

Reply to
aarcuda69062

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So I should have continuity between the two wires. (I have a continuity tester on my multimeter). Also they should have the ohm reading you mentioned earlier while spinning the tire. SHould I check for an a/c reading on one of the wires while spinning?

If only the front sensors are plugged directly into the module, then where do the leads for the rear sensor go?

Reply to
stryped

The front sensor(s) should read 2400-3400 ohms regardless of whether you measure it at the EBCM or at the sensor connector down on the frame. If you spin the wheel, the ohm reading should fluctuate because of reluctance. Resistance spec for the rear sensor is 900-2400 ohms

You can. The actual voltage is dependent on how fast you can spin the wheel so an actual measurement spec is not defined.

I've explained this 2-3-4 times already. The rear wheel speed sensor connects to the VCM , connector C1, cavities 29 and 30. The VCM sends the rear wheel speed signal to the EBCM on a white wire. If the vehicle speed sensor signal is missing or intermittent the speedometer will act erratic or not work at all especially at low speeds. Paying attention to this will save you wasted steps... If the speedometer works then the problem lies between the VCM and the EBCM.

RF>>>>I I>> EBCM

Reply to
aarcuda69062

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