1993 Sierra gremlins

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Magman

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Morning guys. I just purchased a 1993 Sierra for my son and trying to get it road worthy. It had a bad 4.3 which I swapped out, but now it is throwing three different codes that I could use some help with. The codes are: #37 -Brake Switch Stuck ON; #32 - EGR Failure; #42 - ESC Spark Timing Monitor Error.
The brake code and EGR code were there before I changed the motor, the ESC code is new. The new motor runs great, if it weren't for the codes I wouldn't change a thing. Any ideas where to start with any of them? I already replaced the EGR valve and EGR solenoid with new parts. Thanks in advance!
 
Magman said:
Morning guys. I just purchased a 1993 Sierra for my son and trying to get it road worthy. It had a bad 4.3 which I swapped out, but now it is throwing three different codes that I could use some help with. The codes are: #37 -Brake Switch Stuck ON; #32 - EGR Failure; #42 - ESC Spark Timing Monitor Error.
The brake code and EGR code were there before I changed the motor, the ESC code is new. The new motor runs great, if it weren't for the codes I wouldn't change a thing. Any ideas where to start with any of them? I already replaced the EGR valve and EGR solenoid with new parts. Thanks in advance!
Click to expand...

(EST) circuit - open or shorted to ground during engine run or, Direct Ignition System (DIS) fault - bypass circuit open or shorted to ground during engine run.

In simple, DTC 42 is for the Ignition Control Module in the distrubutor. The easiest thing to do is pull the module from the distrubutir and take it to an auto parts store and have it tested. They all (to my knowledge) test them for free.

To remove the ICM - Unhook battery. Take off the distributor cap while leaving all the spark plug wires attached to it and twist out of the way. Pull the rotor straight up and off. The module has the 2 wire plugs attached into it, unplug them and use a small torx screwdriver to undo the 2 screws that hold it on. Have the parts place test it a few times and a new one will be less than 40 bucks if it fails. You can also do what I do is just get the new one, and if it doesnt work, clean it up really good and return it to the youngest guy working there telling them you never needed it after all. :o

Good luck and keep us posted.
 
for the brake one there is the switch under the dash that the brake pedal hits if you swap that out it should fix that code for you.

Brent
 
Sweet! Thanks for the help and pointing me in the right direction. I'll get to both of them tonight after work. I'll let you know!
 
I pulled the Ignition Control Module and took it to my local Schucks/Oreilly parts store, but they couldn't test it. So I remembered what you said and bought it anyway, turns out, it fixed the code. As far as the EGR, after I cleared the codes, it didn't come back. I drove it around for 20 minutes or so with no SES light! The brake switch had to be ordered, it'll be here Friday.

So, no more codes so far! Just wanted to say thanks for the help!;) It's coming along nicely! Now I just need to fix the door hinges, repaint the wheels, degrease/wash the engine compartment, change tranny fluid/filter, shampoo carpets and she'll be as good as new. I'll post a pic after I get it washed up and all shiny looking...
 
Well it's been a few days since I posted here but I should have knocked on wood after my last post. The next day, my SES light came back on and it was EGR Failure, code 32. I spoke with a friend (self proclaimed mech) and he recommended changing the CAT which I did yesterday, still didn't fix it. With th new CAT, it seemed to come on earlier!

Anyway, need some help figuring this one out. I have the 4.3 LB4 VIN Z, how do I tell which EGR I have? I know I don't have the linear type, but the Haynes manual states two other choices, the Negative EGR system or the Ported EGR. Can anyone walk me through some troubleshooting steps? This is getting frustrating. New EGR Solenoid, new EGR Valve, new vac lines, and now a new CAT...Help please!
 
Magman said:
Well it's been a few days since I posted here but I should have knocked on wood after my last post. The next day, my SES light came back on and it was EGR Failure, code 32. I spoke with a friend (self proclaimed mech) and he recommended changing the CAT which I did yesterday, still didn't fix it. With th new CAT, it seemed to come on earlier!

Anyway, need some help figuring this one out. I have the 4.3 LB4 VIN Z, how do I tell which EGR I have? I know I don't have the linear type, but the Haynes manual states two other choices, the Negative EGR system or the Ported EGR. Can anyone walk me through some troubleshooting steps? This is getting frustrating. New EGR Solenoid, new EGR Valve, new vac lines, and now a new CAT...Help please!
Click to expand...

Start with the simple and reinspect your EGR valve and clean it again, pull the EGR and and see if there is a chunk of carbon between the seat and the value. Got to love this design, did you put the reworked OEM gasket in (has a wire mess to block chunks of carbon). ????

Remember, a clogged EGR valve keeping the pintle open which is essentially a huge vacuum leak.:eek:

Keep us posted. ;)
 
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