ABS light fix?

[Eric1971]

ABS light has been on for months on my 1995 4.0 RWD EB. I've had no luck searching for how to pull the ABS codes, one of the few reasons I wish this was a 1996 instead! I tested resistance on the front ABS speed sensors and they seem OK. I thought I had tried to pull EEC-IV codes when it first started, but I tried again today and got a "639 - Insufficient input from the Transmission Speed Sensor". Would that indicate the rear diff ABS speed sensor is the culprit? For $16 for the part, is it worth a try? I did see a post where someone removed and cleaned the sensor to fix it, but a 30 year old part might just need a new one. I made sure the connector was on snug at the sensor. I couldn't find another connector down the line.

Thanks for any help!

 

[410Fortune]

639 transmission speed sensor is not in the rear axle
Yes a speed sensor issue will disable the abs brakes = light

You need a scanner that can pull manufacture specific codes, and during the scan process you will choose the abs module as the one to communicate with and get the codes from

1995 the vehicle speed sensor (VSS) is in the tailhousing of the transfer case
This speed sensor is responsible for driving the speedometer and telling the pcm
How fast you are going

The abs system
Uses its own wheel speed sensors the two up front
Built into the wheel bearings and the third is the center mount on rear axle

The transmission 4r55e in a 95 also has an turbine shaft speed sensor (TSS) this is used by the pcm to control shift points
Your tss may need an inspection of the connector and wires / worst case would need replaced

Code 639...

My OD off light began flashing today in my 95 Explorer. The only code it spat out was 639, which is a fault in the transmission speed sensor circuit. I did drive the truck on a muddy wet trail earlier...is it possible that messed up the sensor? Is it okay to drive the truck? What/where is this...

www.explorerforum.com

 

[Eric1971]

For the ABS issue, cleaning the sensor didn't resolve it. I checked the resistance while I had it out and it seemed ok.

Do I have to take it to a shop for the ABS codes or is there some way I haven't found to read those ABS codes? Seems like this would be so easy on a 1996+.

 

[410Fortune]

Is there an abs diagnostics connector under the hood on a 95?

When you checked resistance did you do it from the wiring at the pump or at the wheel sensor? Need to verify the wiring between wheel sensor and abs module / pump make so no breaks in the wires

 

[Eric1971]

I know where the EEC-IV connector is, but I think there is supposed to be a red ABS test connector. I haven't been able to find it. I have some diagrams and I'm looking now to locate where the wheel sensors are coming into the ABS control module so I can test the sensors from that end.

 

[410Fortune]

Smart

The red abs plug should be over by the heater blower motor?

All 3 wheel speed sensors are wired directly to the abs pump

Might give a look at your transmission mounted speed sensor and wiring/‘connector as well since your code is for the tss

 

[Eric1971]

No luck finding the red connector. You'd think somewhere in the whole wide internet there would be a picture "it's right here" but the '95 is such an oddball between ODB1 and 2 there's just not much good info. I was making an effort to finally resolve the ABS light, but I guess I'll just go back to living with it.

As a last try, I will check the transmission speed sensor.

 

[410Fortune]

Some insight here

code reader for 1995 Explorer

I just purchased an INNOVA 3145 OBD I code reader that is specific for "Ford Lincoln Mercury Domestic vehicles 1981 to 1995". Much to my annoyance, however, the manual lists 1995 4.0L V6, 8th VIN digit 'X' Explorer, Ranger, Windstar as excluded. That is, this code reader will not read the 1995...

www.explorerforum.com

Google ai says your 95 explorrr diagnostics port is under the hood drivers side near firewall

And apparently abs module is communicated with using the obd2 port in dash
PCM uses under hood connector, everything else 0b2 port…
That’s why you can’t find that red connector

 

[Eric1971]

I want to test the sensor signals at the ABS controller end. I found a pin-out diagram, but I cannot find the module itself. One diagram points to the driver side front corner, but doesn't say if that's inside the engine bay or inside the fender.

A pic would be great but any help is welcome. Thanks!

For reference, I'm talking about this part, not the pump.

 

[J_C]

Don't know for a '95 but often the controller is next to the pump. Follow the wires from the pump to it?

 

[amj441]

this is a photo for a 1995 ranger. it may be similar

 

[Eric1971]

No. I found it. The ABS pump (1) looks just like the diagram and is easy to find. The ABS controller (2) is on the inside driver's side fender, behind the battery and below the "engine compartment relay module #3".

Hopefully this will help someone in the future!

 

[410Fortune]

Good job
I could only find pics of it
Knew it wouldn’t be far from the pump
In the next generation of pump they are connected
95 is an odd year

 

[Eric1971]

Latest update: I tested the 3 sensor connections at the ABS controller connection. Fronts both read 1231-3 Ohms, rear sensor read 2000 Ohms. I had already replaced the rear sensor because it was cheap and easy and why not? The old rear sensor reads about 1150 Ohms. Those readings seem ok from what I could find. While I had the battery out to get to the ABS controller, I tested the ABS Main and Pump relays. Both tested ok, 81 Ohms and I could hear both relays click.

I went ahead and pulled the front sensors and cleaned them well before reinstalling.

The ABS light stays lit after starting the engine, and some places I found suggest that indicates the sensors since there's a fault when the vehicle hasn't even moved yet.

I can't find any way to pull the ABS codes. My OBD-II reader just gives me a connection error which I'm not surprised since the 95 isn't legit ODB-II. I doubt any shops have whatever weird special thing is needed to get the codes, but maybe a dealer would? No idea.

The ABS light issue *might* have started after I replaced both front wheel bearings and disc/hubs. That seemed like a pretty straight-forward job at the time and I'm not sure if it could be related. I did take the driver-side disc and hub off, but everything looked ok. I cleaned the shield where the sensor is while I was in there. I didn't do the passenger side.

Things I can think to try without the codes:
- Pull the passenger side disc/hub and inspect around sensor
- Replace both front sensors
- Continue living with the ABS light forever on.

Any ideas are appreciated!

 

[J_C]

I don't know the correct resistance readings for the front wheel sensors your '95 with RWD, different sensor but for my 4WD with them in the hubs, the front were 420 ohms and rear around 1000 ohms. Your '95 appears to use same rear diff sensor as my '98, so the old at 1150 ohms seems about right, but measuring 2000 ohms for the new at the abs controller does not seem right, should not be near twice the resistance. If the old was measured directly across the sensor contacts instead of at the ABS controller, then I'd wonder if you have connector corrosion for the rear.

I found this video about OBD1 ABS on a Ford van, don't know if it applies to your vehicle and seems like a lot of work to set up, but here it is:


I also found this much easier method, but it seems risky until you figure out what fuse 9 does on his vehicle, translate that into what fuse # you need on your vehicle, make sure (measure with a multimeter) that you have the correct terminal for that fuse to ground the circuit instead of connecting power to chassis ground which may melt some wires without a fuse in place to prevent that. Anyway on this video he found it was the master cylinder fluid level switch connector, but he also had the "Brake" light on, but at least it shows a method to pull an ABS code.



Then there's this topic:

How to: Pull trouble codes on 4WABS, very simple

Pull trouble codes on a first Gen Explorer is very simple, only need one jumper and one test lamp or analog voltmeter, or if you no have these parts can use the ABS ligth in the dashboard. - In the ABS test connector (engine compartment, RED CONNECTOR, not same as EEC-IV test connector) install...

www.explorerforum.com

Potential list of ABS codes (might be wrong):

How to: Retrieve ABS trouble codes - Ford F150 Forum - Community of Ford Truck Fans

1987 - 1996 F150 - How to: Retrieve ABS trouble codes - I was digging around on fullsize bronco and found this. Original thread is here: http://fullsizebronco.com/forum/showthread.php?t=165569 Pulling RABS Flashout Code. This routine should be good from 87-92. The 90 service manual gives a...

www.f150forum.com