disel dan

Have 99 quad cab 24 valve diesel 2500 2wd.<br>Suddenly the abs warning lights were on.<br>Brakes are fine and function fine.<br>How can I diagnose the trouble.<br><br>Thanks<br>Andrew

disel dan

I understand that if the lights are on then the brakes are defaulted into standard and not actually good for non skid conditions.

disel dan

Can anyone in tech on this forum help with any diag. on abs lights?

Lary Ellis (Top)

Dan Here is some information on diagnosing your problem. This information is relevent to my 96 model I am assuming it may still be the same in your's. Anyway it should give you a place to start.<br><br> First make sure the parking brake is not on, then look over the hydraulic system to be sure it isn't leaking.<br> Make sure the brakes, calipers and wheel cylinders are in good condition.<br> Check the electrical connections at the control module assembly. The module is under the center of the dash. You can see it after you remove the knee bolster.<br> Check the fuses.<br> Follow the wiring harness to the speed sensors and brake light switch. Make sure the connections are tight and the wiring is not damaged.<br> If you don't find a problem you can output the stored trouble codes in the ECM. The RWAL data link connector is clipped to the underside of the knee bolster. a black plug pointing toward the floor to the left of the steering wheel.<br> Using a short jumper wire momentarily ground out terminal 13 (the black wire terminal) of the diagnostic connector and watch the amber abs warning light on the dash board.<br>Fault codes will be displayed by a long flash, followed by a series of short flashes count the short flashes after the long flash and compare with this chart.<br><br>1. Not used<br>2. Open isolation valve wiring or bad control module<br>3. Open dump valve wiring or bad control module <br>4. Closed RWAL switch<br>5. Over 16 dump pulses generated in 2wd vehicles (disabled in 4wd)<br>6. Erratic speed sensor reading while rolling<br>7. ECM fuse pellet open, isolation output missing, or valve wiring shorted to ground<br>8. Dump output missing or valve wiring shorted to ground<br>9. Speed sensor wiring resistance (usually a high reading)<br>10. Sensor wiring/resistance (usually low reading)<br>11. Brake switch always on, RWAL light comes on when speed reaches 40mph<br>12. Not used<br>13. ECM phase lock loop failure<br>14. ECM program check failure<br>15. ECN ram failure<br><br> Hope this points you in the right direction. If all this is gibberish to you then have a qualified technician look at it. Most likely a loose wire or bad connection you can find on your own when tracing the wires.

Outrider

Also pull rear end cover off and inspect rear guts,plus pull ABS sensor off the top of rearend inspect thoughly.Why do I say this?I use to own a CTD and drove about 5000 mile with no spider gears and ABS light on.Pull the rearend cover off I have the pieces if you want to see them.But not the truck.<br>Warchild no longer among the living.

Lary Ellis (Top)

[quote author=Outrider link=board=4;threadid=6480;start=0#60534 date=1036168828]<br>Also pull rear end cover off and inspect rear guts,plus pull ABS sensor off the top of rearend inspect thoughly.Why do I say this?I use to own a CTD and drove about 5000 mile with no spider gears and ABS light on.Pull the rearend cover off I have the pieces if you want to see them.But not the truck.<br>Warchild no longer among the living.<br>[/quote]<br> Assembles Honor Guard and Fires 21 gun salute over Warchild

Lary Ellis (Top)

Dan let us know if you found the problem, we sort of like keeping up with our patients

Straight6Jeff

One other thing to keep in mind on the 2wd, if you unbolt the front shocks and let the suspension hang at full droop, be sure to move the abs harnesses before you unbolt the shocks. they are routed directly between the ball joint and upper frame. both harnesses were cut in half about 6&quot; before the sensors. A little solder, Heineken and shrink wrap, everything was functional again.

Jetson

I would like to know if the truck has 2 wheel ABS or 4 wheel ABs. Could make a difference...