93 Explorer ABS Diagnostics?

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Dec 9, 2003 | 07:34 AM

Lifted78

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From: Cedar Falls, IA

93 Explorer ABS Diagnostics?

I've tried reading everything I can in this forum about ABS, but it seems most of it is geared to pre-93 RABS systems.

Anyway, here is my problem: My ABS is on solid now and I need to know how to diagnose the problem.

Here's what I've done so far:

I've pulled the sensor from the rear diff and cleaned it. It looks like a metal can and wasn't that dirty. I pulled the plug off it and made sure to clean the contacts.

I unplugged each of the front two sensors and made sure they were plugged in good.

I checked the brake fluid level, it was full.

I checked all three fuses and they were all good.

I did not remove the front sensors because I don't know how they come out. I removed the 10mm bolt on the back of the hub, but the sensor did not come out. Do you have to pry it out?

Also, under the hood there is a red box on the drivers side inner fender marked Anti Lock Test. Is there a test I can run on this?

I have the basic tools; volt-ohm meter, etc. Just missing the instructions to test everything!

Thanks in advance!

John

Dec 9, 2003 | 09:53 PM

Lifted78

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From: Cedar Falls, IA

Nobody has -any- suggestions??

Ok, if nobody here knows anything about ABS... How about a link to a site where I can ask the same questions??

Thanks in advance.

John

Dec 11, 2003 | 02:22 AM

Jet Lizard

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From: Moscow, Russia

The red box you've mentioned contains terminal to service computer that dealer stations use for the ABS system diagnostics. You can't read the ABS without this computer.

If ABS doesn't work at all, there are three possible problems:
1. Wiring to the sensors is damaged
2. One of the sensors doesn't respond to the ECU
3. ABS ECU went bad (the less possible reason)

I cannot accurately remeber how to check the sensors so I won't disinform you with inaccurate instructions. But as I remember, having basic ohmmeter is enough to check if the sensor works. Sorry for such general reply.

With best regards,
Yuri,
Moscow, Russia

Dec 11, 2003 | 07:24 AM

Lifted78

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From: Cedar Falls, IA

ABS Fixed.

I replaced both front sensors and fixed the problem.

FYI, the sensors should read between 1K and 1.4K ohms in the front. Mine were not reading anything. Another forum mentioned that these front sensors can be damaged (indirectly) when you replace the lower ball joints. Mine started acting up 1 week after the ball joints were replaced.

Also, the Chilton manual on the 91-97 X's listed the method to check the sensors with the ohm meter. However, they did -not- match what the new sensors read from Ford. Ford has upgraded the sensor used and must have reverted back to the old settings.

John

Dec 11, 2003 | 07:37 AM

Jet Lizard

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From: Moscow, Russia

John, thanks for letting us know the solution. Also, I will keep in mind that issue regarding lower ball joints replacement (I am going to do this on my '93 Ex soon).

Thanks again,
Yuri

Dec 19, 2003 | 10:27 AM

ldruth

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From: Kent Washington

Glad you fixed your problem. I'm having the same one. How do you get the sensors out to check them. It looks like you have to pull the tires and rotors too?

Dec 19, 2003 | 10:37 AM

Lifted78

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From: Cedar Falls, IA

Checking the sensors...

You do not have to remove the wheels or rotors to check the sensors. All you need is a volt-ohm meter.

1. Locate the connector to the wheel sensor. On my 93, it was up by the frame and has a plastic clip you press down and then pull them apart.

2. Inside the socket you just pulled apart will be two pins. Put the meter in ohm mode and touch the leads to the two pins inside.

3. If the reading is now about 1.1k ohms, then they are bad and need replacing. If they read correct, check the rear sensor on the top of the differential.

If they need replacing, you can *try* to remove them from the back of the hub. Use a 10mm socket to remove the hold-down bolt and then see if you can pull the sensor out. I'm betting you can't.

I posted directions to fix this in another forum at www.ford-trucks.com under ABS repair.

Hope this helps!

John