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Question: And now moving on to ABS issues 2002 C5 1243 code


Motor head!!!!
Feb 13, 2001
Valencia, CA,USA
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
[h=2][/h] A few weeks ago I bought a full ABS module from Craig's list ( $100.00 ) the guy seems like a straight shooter..
He had an 03 that got rear ended and there were no codes PRIOR to that time.

I swapped his ECBM in and I had the EXACT SAME issues! But it did free my original ECBM up to ship out for repair.

Brandon ( ABS FIXER ) did the $ 150 repair AND I had him do the anti surge mod ( $50.00 ) .

Brandon stated he could not get mine to fail on his test rig, but did see my code.
Plus mine was right on the edge of failing ( cold solder / heat stressed pieces ) ...

3 days ago I got my ECBM back from ABS Fixer and Brandon is quite a help !
I have a 1243 code (came with the car ) ...

2 days ago we did water pump, stat N hoses PLUS blew out all the junk in front of the radiator.
While we had that all torn down we replaced the ECBM.OH BTW we changed out the T15 torx bolts for allen's IMHO easier to work with.

BUT the new ECBM did not clear my code... and again was doing the EXACT SAME THING !

Brandon mentioned that if you do not have FULL POWER to the ABS pump motor, he has heard of secondary electrical issues ( bad power lines & connections ) ...

SO the plot thickens.. Today, I changed out my ignition switch assy ( new GM electrical & AC Delco lock cylinder ) .
You can pop the green clam shell off the back of the electrical part of the switch,and inspect the different internal sections of the switch.
Mine didn't look good & and I had to replace the ket switch anyway to repair the REMOVE KEY IN RUN " feature ". So I was hoping that I was getting a mild current limit in the switch....

Prior to this I would start the car ( keeping my foot on the brake, which keeps the ABS from going into self test ) ...
Let the voltage come up on the dash gauge ( which LIES ) .. I have a digital gauge in the cig lighter which is RIGHT across the battery.
Dash gauge ~ 13 volts cig lighter gauge 14.2 volts.

The SECOND I lift my foot off the brake, both voltage gauges dip ( 12.9 across the battery ) I hear the blower motor speed SLIGHTLY reduce...
( 1 Mississippi ) BAM the ABS And traction control lights come on ! Voltage comes back up, and everything is NORMAL.... Well except for the nagging DIC !

So replacing the switch did NOTHING to help my ABS issue...
I had my son put his hand on the ABS pump and he states he can feel it running, for that 1 Mississippi period of time.

So trying for another step forward in solving this.I was looking at different code scanners to activate the ABS and do advance testing ( Like the TECH 2 but I don't want a CHINA CLONE ) ... I realized I had another ABS pump in the garage !!!

I understand that my ABS pump assy may be just gooed up with old brake fluid...
I have read other post's all over the NET that you have to heat up a GREEN WIRE ( wherever that may be ) to force the ABS pump to spin up.
My brake fluid ( when I got the car ) wasn't BLACK but it wasn't pretty & the car has spent most of it's life in florida.
And I have bled all 4 corners so the fluid is CLEAR along with dumping as much as I could from the Rez 2X ( small syringe and aquaruim tubing ) .
So I had another idea.....

So I made an adaptor to hook DIRECTLY to the ABS pump . You remove the 2 pin connector on the bottom of the ECBM multi pin connector.
Take 2 spade lugs ( male ) and cut em in 1/2, so they are 1/2 the width of the spade.... Hooked it up to a 12 volt battery ( with an amp meter ) ....
and 6.7 amps start up leveling back to ~4.5 amp on a DRY ABS pump....

Armed with this information I will try this in the car tomorrow and continue the saga...

I currently do not have a FSM for the 02 and I would KILL for the ABS wiring diagrams...

SO I'm here... more to follow...

A bit more progress

Re cleaned the 3 grounds , 2 by headlight one by frame rail under brake vac booster...
No change...

Verified fuses are good ( Via ohm meter & test light ) .

The ABS pump currently in the car does spin up, under the following conditions.
1) ( With assistant ) Engine on, brake pedal on, code cleared release brake....
2) Hooking 12 volts directly to the ABS pump. I did not measure the current draw but the motor did not feel labored.

So Monday....
I need to find a schematic for the ABS.
Contact ABS fixer ( just to have a where to look next dialouge ) .
Have a good hard look at the multi pin connector AT THE ECBM




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ABS Fixer input

So here is a BRILLIANT test......
Brandon has told me that the ABS ( stage 1 ) self test is monitoring the current draw to spin up the pump...
SO I'm going to make an extension so I can connect the ECBM module to my 2nd ABS pump assy and see if I can get past self test. I do have some other grounds to do ( just cause ) and a CLOSE INSPECTION of the ECBM multi pin connector....

BRILLIANT ! I have to say That Brandon is "ON BOARD " to making this work with me... and THAT is customer service !!!!!

So happy I'm not holding the bag SOLO!

Able to pass self test on C5 2002 work in progress

So 1 HUGH step forward…..
I got up at midnight and made an extension so I could hook up my loose ABS pump to my repaired ECBM.
This morning , I took apart & cleaned the ground by the battery, since I had not done that yet. No change in the ABS issue though.

So I jacked up the car, removed the ECBM connector and disconnected the existing pump and hooked the output to the ABS pump on the top of the car...

Cleared all codes and started the car… AND NO CODES RETURNED !


My abs pump has a few shorted windings...

The Spare drew ~ 6.5 amps on start and leveled out to 4.5 amps.

The existing pump blew the fuse in my amp meter ( 10 amp full scale )...So it MUST be drawing more ( ya THINK ? )

So for the INITIAL ABS test the ECBM measures the current draw from the pump…
Once THAT passes I could still have other codes, but the car needs to roll down the road to get to the next level of internal self test.

So when the 1243 code is thrown it's not just a STALL in the ABS pump motor, it's over current, either from the motor is seized OR shorted windings.
My pump did RUN !

So I'm not out of the woods QUITE YET.

I do not have a scan tool that will operate the ABS functions. ( yet )

In order to do a PROPER brake bleed I need to activate the GM Auto bleed procedure..

The 2 shops that WOULD do the job wanted 400 to 450 ( remove the ABS full assembly, use the ABS fixer ECBM, re install & bleed )

Since it was a USED ABS pump there would be NO WARRANTY.

At that price I can buy a China TECH 2 scanner !!!!! ( that didn't workout, see below )

So a BIG SHOUT OUT to Brandon at ABS fixer……. AGAIN !



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    ABS on firewall.jpg
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BPMV research

I ASSUME that this is a simple procedure.. BUT I also understand to do a PROPER brake bleed you need a scan tool that will do BI Directional functions, like turn on the ABS pump and close the wheel solenoids in the pump / valve body. Has anyone done this recently.. and have a walk through? I would really like to do this right the first time..
I have a scan tool on the way, the current GM china clone will NOT do this function according to the seller But the Foxwell NT 630 PRO will...

A theory on the BPMV to fix 1243 , and the BEST course of action....

Speculation....Looking at the 1998 FSM Hydraulic internal map of the BPMV, there seems like a fair amount of nooks & crannies controlled by the solenoids that would keep air in the system IF the ABS wasn't engaged.. A conventional bleed was done your pedal might FEEL FINE until the ABS kicked in , post that event you could have anywhere between a mushy pedal to Pedal to floor itis, I guess I could make the repair PRIOR to the scan tool arriving, verify that the codes were cleared and then pull the ABS FUSE. But that seems like 2X the work ( jack the car up,jacks in 4 corners Wheels off/ bleed / wheels on ). This could be a case of procrastination could be profitable..... sigh..
Almost there.....

Well Not much to report EXCEPT I bought s Foxwell NT-630 scan tool which does ALL of the ABS test functions, ABS pump activate, test solenoids, "GM" auto bleed. so I can do everything I need to on the first shot. $180.00 from Flea bay. Yes it is a china POS BUT it seems to do the trick. I am now waiting for the pressure bleeder from ZIP.. and between all that my starter is getting intermittant. it's just so freakin HOT in so cal these days..... I wussed out and took the starter motor job to the shop...

C-1243 code epilouge

Swapped all the ABS out ...
Used the Craigs list PUMP
Used the repaired ABS Fixer ECBM.
Re bled the system 2X ( lotta junk in the fluid )
BAM Nuttin but WIN. Codes GONE....
So MY PROBLEM was the ABS pump motor was drawing to much current on self test... and threw the code.

I EVEN caused some ABS activation on the test drive...

So on to the next item.....

YEA! :happyanim::happyanim:
1 down! Now move on to the next one.
Good luck with it!
Andy :w

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