Hi guys,

and thank you for a brilliant forum which has helped me a lot already. I bought a 1994 4.3 4X4 Blazer a couple a weeks ago and the only thing I have left for the EU approval (to get my license plates) here in Norway is to get the ABS dashlight to go away! Its been on since I got it and its on when I turn the key around. Before I got the car it had not been used for a year, and they just changed the left front fender (?) inner and outer. Is there any ground wires attached to this that they might forgot to reattach? I mean, the ABS unit is located just above this and they didn't really finish their work. And is there a fuse for the ABS in the engine compartment on this car? If so, where? When I jump the terminals A and H I get error code 42 and some other codes within the same range in the Haynes book, that tells me that there is something wrong with "circuit at motor" or that the ABS unit is faulty. I've tried to check the front sensors and I get reading around 1200 ohms on both sensors when I turn the wheels. Although the shield is pretty corroded and they have probably been on for a while! I've got hold on a unit from a 1992, is it just to put this on my 1994 and try? Its just the front of the whole unit with the two connectors I have, I guess this is the electrical part of the unit? Any help or input is highly appreciated!

Petter from Norway

 

Got the codes 51 and 52 last night, anyone who knows what these codes are specific? Thanks!

 

code 42-right front ABS pulse-width modulation valve...51-rear ABS isolation valve and 52-rear ABS pulse-width modulation valve. Maybe this will be some help...gotta love messing with other peoples work..huh??..lol. This is just my opion on getting codes definitions for anything...dont always rely completly on a Hanynes book that are for certain model vehicals, there definitions not always spot on or explained very well, find a book for the specific thing you need such as a book just for brakes to break down all thangs brakes and better definitions!!...and Haynes make these also and they are lot better at explaining than their certain model full manuals are, think they try to save space in those manuals and take short cuts....just my two cents

 

Thank you! Do you know what rear ABS isolation valve and ear ABS pulse-width modulation valve are? Is the isolation valve the valve inside the ABS unit? Could this be caused by dirt in fluid or is it just that the whole unit is faulty?

Today I did some research to try to figure this out. I unpluged the rear abs sensor thats in the transfer case and then I got code 67 (Open motor circuit or shorted BPMV output OR Open motor circuit or shorted VCM output). When I removed the sensor from the transfer case and pluged it in again I got code 66 (Pump motor relay or circuit shorted-VCM). When I installed the sensor in the transfer case and had it pluged in again I got code 65 (Pump motor relay or circuit open-VCM OR Pump motor relay or circuit open-VCM) and code 51 (Rear isolation solenoid or circuit open-VCM). Is there anyone who can see a pathern here? I thought maybe I should try to replace the rear sensor. Am I way of??? Anyone?!

Is BPMV the little unit behind the glovebox closest to the glovebox? Could it be an idea to try another BPMV from another car? Could I use one from a 1992 model??

 

stuff i have heard on that unit is that those valves pick up trash causing fluid to pass by which causes pressure issues...im just gonna go out on a limb here and assume when they changed that inner fender they took this unit off also? if so then im thinking more like that unit has a poor ground or is full of air causing some of these codes??

 

The BPMV is in the engine compartment, driver's side. Has 3 electrical connectors (I think, could be 2) and at least 4 metal brake lines. You can replace it from another Blazer/Jimmy/Bravada/Astro, 92-94 definitely and '95 possibly.

 

As far as I have understood this the ABS unit in the engine compartment consists of the BPMV and the EHCU and is possible to split. Would it be a bad idea to split the EHCU and BPMV and just try the EHCU from another car on my BPMV or are these calibrated together? I dont know if it is the BPMV or the EHCU that usually is faulty, but it would be way easier to try this than to bleed the whole system, unless its a really bad idea...

I tried a different rear abs sensor today, and after I reset the codes I got code 12 (?) and then code 26 (front left sensor). Turned off the ignition lowered the car down again. When I checked the codes again I got 51, 52, 66 and 67 again. Any ideas? I am really running out of ideas here... Would highly appreciate some help...!