1st Gen Abs codes and how to retrieve/clear them
 

1982-1993 s10/s15 1982-1994 s-series blazer jimmy (1st gen) ABS trouble codes list as well as how to retrieve and clear codes.
Took me awhile to find this and 94blueknight has also said he could not locate the list so hopefully this will be of some use to others
The system in these trucks is Kelsey-Hayes 4WAL ABS this is a 3channel system, right front, left front and rear axle.
The resistance specification for each WSS is 1000 to 3000 ohms, which can be measured at the ECU connector.
The rear axle is regulated throught the VSS, its signal first goes through the Digital Ratio Adapter Controller (DRAC). The DRAC converts the AC sine wave from the VSS into a 50% duty cycle square wave. It then sends this signal to the ABS, speedometer, PCM and cruise control module, adjusting the ratio for each svstem. If the rear end ratio or tire diameter has been changed, the buffer should be replaced with one calibrated for these factors. If only tire size has been changed, a Tech lA scanner can be used to reset the ratio.

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A code key or jumper can be used to short ALDL terminals A and H to retrieve trouble codes on the 4WAL system. To begin, first make sure the brake pedal is released. Next, turn the key on, insert the code key or jumper A to H and wait for the ANTILOCK light to flash.
The process for erasing codes on the 4WAL system is a rather unusual fivestep procedure:
1. Turn the key on.
2. Insert the jumper or code key into the ALDL and short terminals A to H for 2 seconds.
3. Remove the jumper or code key for 2 seconds.
4. Reconnect for 2 more seconds.
5. Disconnect the jumper or code key.
If the ANTILOCK and BRAKE lights come on for a couple of seconds, then stay off, the codes have been erased.

Brake Pressure Modulator Valve and Electronic Control Unit. As noted earlier, the BPMV and the ECU are bolted together and serviced as a unit. There have been some cases of the BPMV leaking fluid into the ECUs circuit board on applications where the assembly is mounted with the ECU on the bottom. If there is a mysterious loss of brake fluid on these applications, don't automatically condemn the master cylinder.
Bleeding the BPMV is rather complex on the Kelsey-Hayes 4WAL system. A pressure or vacuum bleeder is preferred over using the brake pedal for this procedure. If the pedal must be used, consider removing the master cylinder to clean the reservoir, then bench bleed it to flush out any debris. If a new master cylinder is being installed, be sure to bleed it before installation. When vacuum or pedal bleeding, don't let the master cylinder reservoir run dry! Once air is bled from the master cylinder, the BPMV can be bled as follows:
1. Open the internal bleed screws a quarter- to a half-turn. These are the cap screws on either side of the BPMV
2. Attach special tools (Kent-Moore No. J39177) to hold open the highpressure accumulator bleed valves.
3. Open the two bleeder screws at the BPMV and bleed the unit.
4. Bleed the wheels in the following order: right rear, left rear, right front, left front.
5. Retighten the internal bleed screws and remove the tools from the high-pressure accumulators.
6. Firmly depress the brake pedal and perform three to six functional tests using either a scan tool or the jumper method described earlier. This forces remaining air from the BPMV into the lines running to the wheels.
7. Finally, bleed all four wheels again in the following order: right rear, left rear, right front, left front, to remove any air that was expelled from the BPMV. Note: This procedure should be necessary only if the BPMV is being replaced. During routine service, the system can be bled normally at the wheels.
If the BPMV is replaced and the procedure just described is not followed, air may be trapped in the hydraulic circuits that are normally not exposed to the regular braking system. Only after an ABS stop will this air be introduced.

Now onto the codes!

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I know it’s not the prettiest thing in the world but hopefully it will work for now and as soon as I have the time I’ll type it all up manually to make things a bit easier to read.

All pics are in thumbnail size to save screen space just clicky them to enlarge.

So to retrieve the codes, short out terminals A and H and the code will be displayed with the AntiLock light on the instrument panel, correct?

I'm glad this has been posted, I looked about a year ago to find information about codes on the ABS on my friend's '91 Blazer, and all I could find was somebody telling me to jump a wire under the dash, but no information on what the codes actually where. This is a huge help, thank you very much for posting this!

Just curious where you found these codes. I have a 94 Blazer and actually broke down and bought the factory manuals (not cheap but there was so much wrong with my little creampuff it has saved me 10 times the cost in frustration alone) but these aren't the codes in my service manual. I'm getting a code 13 and it doesn't show up in my book. Unfortuneately if your code sheet is right my ECU is shot. Also when I hit 15 mph the "Anti-Lock" light comes on and doesn't go out until I decelerate below 15 mph. Any ideas? I'm a pretty good mechanic and have sure learned a lot semi-restoringt his jewel.