ABS Light on

[Mike72771]

My ABS light has come on a couple of times. I just slap it in reverse, gas it, crunch the brakes and toss it back in drive. No more ABS light.

I assume its just a dirty sensor. It only comes on after its been raining for a couple of days.

[wb4lbg]

Well, I'm a little more confused this morning than I was yesterday. I pulled the connectors on the front sensors but couldn't get my meter leads oriented to read the sensor resistance. The female part of the plug is pointed up and toward the wheel well so that the pins inside are pretty much inaccessible.

I did, however, measure the resistance on the male ends of the plugs -- 700K on the driver's side and 820K on the passenge side. Since I don't know what these values are supposed to be, it doesn't really help me much.

As for the rear wheels... The Haynes manual (and other posts that I have read) says that on the 4WD models, there are sensors on each rear wheel. I looked a little closer last night and I believe that what I thought were rear wheel sensors are actually where the parking brake cables enter the rear wheels.

As far as I can tell, there is one ABS sensor on the rear differential like on a 2WD. Anybody know if there was a production change from 2 rear sensors to one sometime in the 99 model year? Maybe the rear axle went out in this thing and someone installed one out of a 2WD junker? How could I tell? Maybe this is the root of the ABS problem?

Slamming on the brakes in reverse, eh Mike72271? I'll give it a try. At this point what can it hurt?

JWS

[Letsrodeo]

I've discovered a way to trouble shoot the ABS Diagnostic Trouble codes (DTC) by using the ABS warning lamp. Basicly you jumper pins 12 and 4 of the OBD II scan port (DLC), turn the key switch to the on position. The ABS light will flash out the DTC.

Attached is a link to a .pdf file I created that gives the procedure with the DTC code descriptions. The description identifies the components that are the source of the problem.

ABS DTC.pdf

[rodeo02]

You da man LetsRodeo!! That is AWESOME info.

Joel

[fdu98]

where is the ehcu anyway?
also..i have seen on the msn site...stating that the abs light maybe due to a bad wire harness..anyone know anything about this?
where is the rear wheel speed sensor wire harness anyway????
thanks

Originally Posted by Letsrodeo

I've discovered a way to trouble shoot the ABS Diagnostic Trouble codes (DTC) by using the ABS warning lamp. Basicly you jumper pins 12 and 4 of the OBD II scan port (DLC), turn the key switch to the on position. The ABS light will flash out the DTC.

Attached is a link to a .pdf file I created that gives the procedure with the DTC code descriptions. The description identifies the components that are the source of the problem.

ABS DTC.pdf

[Letsrodeo]

the 95 Rodeo was notorious for having a poorly designed wiring connector.......

On my 99 Rodeo the rear sensor is located on top of the rear differential and the wiring is routed to the driver’s side. The second connector is just inside the rear driver’s side wheel well. The first is at the differential.

I found two wires busted loose at the second connector as well as a bad rear sensor on mine. The connector pins can be removed from the plastic housing. That’s what I did and soldered the broken wires back on the pins. Disassembling the connector is a pain.

I bought my rear sensor from St Charles Isuzu (http://isuzu.stcharlesauto.com). for ~$56.

[fdu98]

i did see a black box on the diff. with all these brake fluid hoses going in
is this the ehcu?
or is this just the sensor?

[Letsrodeo]

Barring the differences are minor between your 98 and my 99 Rodeo. The EHCU is under the hood on the passenger side fender.

The rear sensor is on rear differential on the topside towards the front. You have to crawl under the axil from the back of your Rodeo to get to it. It only has wires (a cable actually) to a connector clipped to the top of the differential.

The sensor has a hold down clamp secured by a bolt.

[sporkman]

Does anyone have a picture of the speed sensor on a 97 rodeo or a year that would have a similar set up. I have a Haynes manual, but as someone said earlier it is pretty useless when it comes to the ABS system. I just want to make sure that I am screwing around with the right parts. Thanks

[highlandlake]

Originally Posted by sporkman

Does anyone have a picture of the speed sensor on a 97 rodeo or a year that would have a similar set up. I have a Haynes manual, but as someone said earlier it is pretty useless when it comes to the ABS system. I just want to make sure that I am screwing around with the right parts. Thanks

I have a 97, and replaced the speed sensor this year. It's dark most of the time here and the driveway is covered in slush and road salt so I can't send a photo any time soon. But it is located on the center of the rear differential. Right on top. You'll see a thin black wire harness that is clipped to the diff. It's hard to reach unless you jack up the vehicle and get as much clearance as you can. Get a good shoplight under there too. Disconnect the pigtail. There's a 12mm or so bolt holding it to the diff. The bolt is about an inch long and easy to get take off. Now the fun part........to get the sensor out you have to wiggle it a bit at a time while lifting up. There's an O-ring that is keeping it so snug. The bolt flange is plastic and I cracked mine by trying to jimmy the thing upward. Was more cafeful with the new sensor. Eventually it broke suction on the O-ring and came out. The new one goes in pretty quick and easy. It's a good time to check the condition of the brake lines, shocks and other underside items. I replaced the fuel filter while I had the thing jacked up. Hope this is helpful info. Highland

[jamesh4]

Good Post LetsRodeo. I had my ABS checked at Pep Boys and they charged me $400 to replace the rear sensor they said was bad. I should have done it myself but didn't have the knowledge of the Rodeo's ABS that I have now. The light remained on after the repairand the mechanic told me the sensor was bad and needed to be replaced but now there is also something else wrong. He would now try the next thing for another $400 but no guarantees. Forget that, I can guess as well as the best of them and cheapter too. Based on LetsRodeo's post, after jumping pins 4 and 12, the ABS light sequence I am getting are:

12 - this is the regular DTC start
53 - Rear Open or shorted sensor
63 - Rear Missing sensor signal
63- Rear Sensor signal dropout

So it seems he was heading in the right direction but the mechanic never checked cable connectivity. I suspect this is the true problem. I'll try this myself but I hate tracking down cable issues.

[jamesh4]

Finally, the ABS went off.

The problem was a broken wire. I did a continuity test on both the white/blue and the orange/blue wires from the ABS connecter under the hood to the differential sensor connector and found the white/blue wire had no connectivity. The test was done by pushing a paper clip into the ABS connector and connecting that to the positive terminal on the battery. Then attaching a simple 12 v probe (the one with the light bulb on the inside) to the sensor connector. Note that if you can't get a good ground on the body you can run a wire from the negative terminal to the back of the car and touch the other end of the probe to that wire.

So I cut the wires about 6 inches from the connectors and attached a test wire between the two connectors and did a continuity test to ensure the connectors were OK. They were. I then ran the new wire along the body to the back making sure the wire had some room to move where the frame and the differential met and made sure it wouldn't move too much when it was close to parts that could get hot or moved in some way. Then I drove it to ensure the light would go out. It did after about a quarter mile of going over 8 mph. After that all that was left was taping and ensuring everything was secure. Finally got that darn light to go out.

[Lomotil]

'99 Rodeo - My dashboard light just turned on two days ago and has been on ever since.

Apparently, it's a safety feature to remind you that you
yanked the 60A fuse to the damned ABS system right
after the gentleman in front of you decided to stop
halfway into the intersection when the light turned
yellow - and you were left to ponder colliding with his
brand new Dodge pickup bumper or jerking the wheel,
jumping a curb, and bouncing down the grassy hill, while
your vehicle loftily comes to a gentle stop.

I hate ABS.

Not that I'm bitter or anything.

I can understand having it in an area that actually has a "Winter" in any sense of the word, but it's absurd for the manufacturers to tack it on to most every vehicle sold in a region where we see icicles seldom enough that most of us need spellcheckers when we type the word (twice a decade, if even that.)

I will say this - that Rodeo is a friggin' tank. As much as I might piss and moan about the smaller details, I still love this thing.

[ericdo49]

I have an intermittent ABS light with codes pointing to the rear. I had the rear sensor replaced and that didn't help. It seems to be a wiring thing. I read here that someone redid the connector on the left by the shock and it had a broken wire. He said that it was a pain to take the connector apart. Can you just bypass the connector and solder the wires directly?

[jamesh4]

You could try to solder the wires on directly but I would first try to see if the problem is really the connector or a broken wire. Odds are, it is a broken wire as those wires take a beating. Do a connectivity test through the connector pin and if you don't have a connection, then do a connectivity test with the wire itself (not through the connector). If you do the soldering first and the problem is a wire but not the connector, then you may make the connector unusable at that point even though it was still good. That could make future repairs to the ABS unit very challenging. Just my 2 cents.