why can't i pull codes for anti-lock light (abs).

S

skata

Donating Member
well i found out previous owner of my truck pulled out the dash bulbs for the anti-lock(abs) and brake light. :evil:

so i put in some bulbs. both the abs and brake light were on. the brake light went off after a little while with the truck running.

the problem i have is that i cant pull any codes from the abs. the abs light is constantly on with the ignition on. if i jump the A and H terminals on the diagnostic port, the abs motor kicks on for a second and the brake light goes off, but the abs light stays on and NEVER flashes.

i'd like to keep my abs, so i'd like to fix the problem instead of yankin out the dash bulbs. :roll:

also, does the main ecm control the abs unit?
 
T

truckins10

Member
To get codes you...
1. cross A+H for 2 seconds
2. remove for 2 seconds
3. then cross A+H for 2 seconds again

This will cause the ABS light to start flashing codes. The ECM has nothing to do with the ABS, thats why there is an ABS module on the ABS unit(unit with all the brake line joining to it).
 
S

skata

Donating Member
sportsmachine site said:
To do a diagnostic on 4WAL codes you take a paper clip and connect terminal (A) and (H) together. After 20 seconds if any codes are present they will be displayed by the flashing of the Anti-Lock light. A code is displayed for example 12 (1 flash, pause, 2 flashes). Listed below is a list of all the available codes and what they mean.

To clear the code from the ECU memory, with the ignition On, place the jumper between (A) and (H) for two seconds, remove for one second, and replace again for two seconds. The Antilock/Brake light should light, then go off.
Click to expand...

what you said tells me how to clear the code. well that dont work either.

so is everything that controls the abs inside the unit itself?

is the abs dash warning light coming from the abs unit itself?

i just want to be sure that my abs unit is at fault, and not some other sensor or computer.
 
J

jdeangelis

New member
I'm having a similiar problem. What did you do? When followed the trouble shooting guidelines it tells me that the unit has failed and to replace it.
 
S

skata

Donating Member
well, i ended up putting a rebuilt abs unit in the truck. i guess my original abs unit's brain failed. the new unit works good. there is no more constant abs light on.
btw, all abs functions are controlled by the computer that's inside the abs unit.

what codes are you getting? a false "ground" code is common.
 
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