Chrysler Repair: ABS light on 89 D150:code 9, manual roland, bosch abs

Question
QUESTION: Hello Roland:

I am working on my 1989 Dodge D150 pick-up. Both the amber ABS & red BRAKE lights are on. It is a 2WD with 3.9 V6, manual transmission, 106,000 miles and only rear ABS. I am

not having any braking issues, but would like to trace and correct the cause of the ABS light being on. I tried plugging in my SnapOn scan tool to see if I could read any ABS codes, but

the 1989 system apparently does not provide ABS data where I can access it with that scan tool. I had to replace the battery recently, which cleared the codes for a short time, however  

after a few start/drive cycles, the lights have reappeared. Could you please advise how to trace issues on that system?

Thanks,

John

ANSWER: Hi John,
I don't have any truck manuals but the '89 car manual for the Bosch ABS-3 system describes how to get fault codes:
Becuase codes are erased when you turn off the ignition you need to first turn on the ignition. Then release the parking brake. Then watch for the ABS of Brake warning lamp to come on. Then step on the brake and hold it. Then hold the pedal for at least 5 seconds to see the brake warning lamp start to flash. Count the number of flashes which is the fault code number. Let me know what counts you get. You can keep holding the pedal and it will do the fault code count again in about 10 seconds. That is the procedure for that specific model of abs. If you believe you have a different model let me know as I may have it in another car manual.
Roland

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QUESTION: Hi Roland:

Thanks for the info. Sorry to bother you with this as I forgot that you didn't have truck manuals.

Unfortunately that didn't work. As soon as I turn the ignition key ON, both lights are illuminated and when I release the parking brake and step on the brake pedal, nothing happens. I tried it several times and the lights are steady. The only difference is that the red BRAKE light is brighter with the parking brake engaged. I suppose it is a different system. If you find anything else, I'd appreciate it.  

Thanks again & take care,

john

ANSWER: Hi John,
If you could look at the ABS controller and identify a manufacturer/model # then I could look for that in my manuals.
I wonder whether because the brake light is 'on' might it be the case that there is an imbalance in the pressures of the two sides of the split brake fluid system as the result of a leaking wheel cylinder/caliper. Have you checked for that or have you noticed any loss of brake fluid over time/stripes of fluid on the inner sidewalls of any of your tires? If that were the case it might have caused both brake warning lights to come on.
Roland

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QUESTION: Good morning Roland:

I found the controller behind the glovebox. It doesn't have any manufacturer identification on it that I could see other than the Chrysler Pentastar and a part number. I didn't remove it to check the back side though because during the course of my investigation, I noticed the light flashing after I had the key on at one point. I don't know what I did to get it to flash, but it flashes 9 times, stops for 5 seconds and flashes 9 times and continues that cycle. Does that help?

Thanks,

John

Answer
Hi John,
If it is a Bosch ABS-3 then 9 flashes means there is a discrepency between the left front/right rear wheel rotation speed sensors. Are the tire sizes identical on those two wheels? If not, that would cause that fault code.
Other than that, futher diagnosis of that code requires use of tha Miller Special Tool 6100 which tests for electronic problems and their diagnosis/repair.
The 9 code can also be set intermittently by slippage under hard acceleration on ice or slippery surfaces.
Roland
PS Thanks for the rating and nomination, John.
I thought of suggesting that you clean the sensor and 'tone wheel' of those diagonal wheels, but after looking into the details I see that in this model the sensor is designed to mount in housing that contains the bearing and there is no tone wheel as such, nor would dirt normally get involved as with the current generation of ABS. So it would appear that an electronic diagnosis with the 6100 tool is necessary.