ABS troubleshooting

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Sep 1, 2017 | 07:05 PM

Travi

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ABS troubleshooting

1999 4.2L 2 wheel drive with 340,000 on it. Abs light is always on. Idles around 850 while in park. Drops to 600 when in drive. Brakes smoothly but it seems like the engine is fighting the brakes when I try to slow down. Engine is newer than the truck. Was wondering if ther is a sensor that tells the engine to calm down when the brake peddle is engaged or something. pls help.

Sep 1, 2017 | 08:42 PM

steve(ill)

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no expert, but here are the basics.
Turn the key "ON" (maybe startup) and the ABS will light up.. checks continuity to all wheel pickups, then lite goes out in 5 (?) seconds.
Start truck up and put in gear if light is off... at about 5 MPH a comparison is run between each wheel to see if they are all turning the same speed... If the light comes back on, then sensor is connected, but is not picking up a signal.

Sep 2, 2017 | 12:45 AM

Travi

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I put the key into start position and the abs light turns off after a few seconds but then it turned on a second later and stays on

Sep 2, 2017 | 08:00 AM

projectSHO89

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From: St Louis

If the ABS warning light is on, that means that the function of the ABS system is offline (disabled).

The ABS system is not the cause of what you reported as a drive-ability symptom. Most likely, either nothing is wrong or you have an issue with the IAC valve or, perhaps, an intake leak (which would be expected to post a MIL).

Sep 2, 2017 | 11:10 AM

Travi

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I had on OBD2 reader do a check on my engine because it was throwing a code but both codes were "running lean" and a "poor exaust read" because my catalytics were leaking. I cleared the codes and fixed the exhaust leak and the codes have not come back but the running condition has not changed. I have replaced all my filters and recently done an oil change and still nothing has changed aside from the truck being more quiet. Next on my maintenance list is to do spark plugs and wires if they need to be done. I do have a leak where the rear of the drive shaft meets the differential and it has a sensor on top of the diff, I can't remember the name of the seal, but I have looked into it and I can get it fixed for around 300$. I have no other codes showing up aside from the ABS light. Also, when I cleared all my codes, the ABS light stayed off until I drove the truck about 40 feet. Thank you for helping me.

Sep 2, 2017 | 02:33 PM

Travi

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Changing Gears

I have a separate issue aswell. I have just gotten my rear diff fluid replaced and it has helped with some of the rough idle when in drive or reverse, but I still have a lot of movement when I shift gears. The truck moves a lot and kind of makes a clunking sound whenever I change gears. Also when I shift through neutral into another gear, like from reverse to drive, the motor trys to go up to 900rpms when it passes through neutral, and then it grabs the new gear and the RPMs lower back to 600-650. I took a look at the IAC and it looks old (the metal on the outside is slightly corroded. Is 600 the proper idle or should it be around 800? And is the clunking noise a sign that I have play in my driveshaft or is it because of the idle change affecting the gears, if so how do I trouble shoot? I would appreciate any help please.