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Discussion Starter · #1 ·
Hi guys..I think i may have inputted this before in early 2000s....however I am self fixing if possible the ABS light that comes on after moving around at least a certain speed and distance...it resets when u shut the car down...

I had the car up doin both calipers and while up...i spun the wheels...each side made the light come on...I then had the rear end up and put in drive...and the light did not come on...I said wowwee i found it but when I got in under the back seat to check for voltage etc..i found 4 wires,two mights been grounds...but with all four disconnected going to that through the floor connecter...the light came on even if i turned the key on...well i said it cant be the rear end one cause i was getting voltage out of the two small wires..so i put the wires back together and back to the original problem I have had for 16 yrs or so.

the next test will be to get in there somewhere and disconnected the front sensors and see i get the same voltage reading when the wheels spin to make a current AC... so if all sensors are good in that respect then I wonder what it could be..maybe the squrrils got in there and chewed a wire !

my wish is to get a full schematic for the ABS sensor system..then I can go to town maybe...but the 4 wires in the rear end line got me confused as in my grand marquis that I just fixed..only two wires in each wheel sensor...does anyone know why 4 wires in rear end...I am imagining maybe a photo light going and returning a signal when moving..these systems were fairly new in 96 ...they tell me that the dealer has a reader that can read the early systems..i wanna try and do this myself for the experience...

amyone got a schematic that can post in here for me...thanks and any tips..

I will check often in here
 

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Diagram:

Information:
I find it easier to read the text if I do Ctrl+A(select all text)

From memory if the ABS waits until the self test (speed check and pump check) to turn on the light it thinks all sensors are connected. This does not mean it is getting a wheel signal and could mean the pump or valves failed.

You can play around with your meter or find someone with the rare scan tool that will read a 1996 and one of the 13(?) codes may tell you exactly what is wrong.

The FSM has pages of diagnostics for each trouble code.
 

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Discussion Starter · #4 ·
Where are you located?
Same size front and rear tires?
Ever had rear end work done ?
Ratio change ?
I am in the Halifax Nova scotia Canada area...no rear end work done....yes on same size tires...no on ratio change..but I bet its dirty inside each sensors area.. thanks for your interest,i got the schematic as u see above.
 

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Discussion Starter · #5 ·
Diagram:

Information:
I find it easier to read the text if I do Ctrl+A(select all text)

From memory if the ABS waits until the self test (speed check and pump check) to turn on the light it thinks all sensors are connected. This does not mean it is getting a wheel signal and could mean the pump or valves failed.

You can play around with your meter or find someone with the rare scan tool that will read a 1996 and one of the 13(?) codes may tell you exactly what is wrong.

The FSM has pages of diagnostics for each trouble code.
Thanks for both docs ,i have printed them off...I will get the front plugs apart at the frame somewheres and check for AC being made on each one and then try and get off all three to clean them well..probably all dirty. then later on...I will get right at the control unit and see if the circuits are good right from the sensors back with AC being made...Ok on the pump being bad too maybe.....if so it may be real job to get a new one as the dealers are not stocking much...I find it crazy that they drop support..even if it means keeping one of everything that goes bad and then re ordering from a central point.Geeee I guess the local gov motor vehicle people would have to give ya a break if u cannot get replacement parts to keep stuff working..Rockauto has the sensors,they may have pumps too...things to do down the road..thanks again.
 

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I do not know about the current market but in the past a little research found small and large companies that remanufactured ABS modules. Searching for Impala or Caprice ABS modules may not find them but some may still offer the service. Used with a warranty is also a option. I would not worry about the pump unless you have a code for it.
 

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Easiest/cheapest solution is to delete this rather primative system altogether.
 
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Easiest/cheapest solution is to delete this rather primative system altogether.
In Canada we can have issues with required Provincial or insurance inspections. The insurance also asks that you inform them of any mechanical modifications. I expect legal issues if the fine print is not properly responded to. "Insurance inspections" usually start a 20 years. There are companies that do not require this but you pay for it.

Several Provinces are also the mandatory insurance provider: British Columbia, Saskatchewan and Manitoba.

The "out of province" inspection in Alberta requires all systems the car was manufactured with be operational on the car.
No ABS, no Air Bag, no DRL and the imported car can not be registered.

Like the US liability lawsuits can be filed over modifications to safety equipment.
 

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Fortunately we are not require to have any of this.
Consider the millions of cars here that never had any of it.
 

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FYI, each front wheel sensor only has 2 wires. Rear axle only has one sensor and two wires on the diff.

Unplug and put a multimeter across each sensor should get you an ohms reading. I don't remember how much off the top of my head. But try each one and they should be about the same. In the K range.

The harness under the rear seat may have more than just ABS in it, I can't recall from memory. But I do know that section of harness that goes under the car from that connector to the ABS sensor plug can be problematic. And I've have 2 cars over the past 25 years with that bad section. It may test fine most of the time. So it either fails intermittent or high impedance... and hard to catch. Replacing the harness between the connectors solved the problem. I had spares. In your case, I'd try cleaning the plugs really well first. Use something like Deoxit and a pick. Especially that connector underneath the seat area. If you are good with wiring, try building a temporary bypass harness of your own (get creative) to see if that helps. Focus on that rear sensor and harness first.
 

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I would check the small yellow connectors on the front wheelhouses, and the one along the left frame rail for the rear. They are notorious for spontaneously disintegrating. When the disintegrate, the wires can touch, and cause a malfunction of the ABS. The best remedy is to separate the connector ends, and slip a piece of shrink wrap over each one.
 

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I would check the small yellow connectors on the front wheelhouses, and the one along the left frame rail for the rear. They are notorious for spontaneously disintegrating. When the disintegrate, the wires can touch, and cause a malfunction of the ABS. The best remedy is to separate the connector ends, and slip a piece of shrink wrap over each one.
Agreed. And clean them really well while you are at it. We are talking about very low voltage here, so even the slightest oxidation on the pins and holes can cause erratic readings, setting the ABS light.
 
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