Trying to pull ALDL code for 1990 C4
Thread Starter
7th Gear
Joined: Nov 2020
Posts: 7
Likes: 1
From: Augusta, GA
Trying to pull ALDL code for 1990 C4
My Air bag warning and seat belt lights are both on.
I'm trying to correct using info found here.
1990 C4, 31k miles, near showroom condition. Recently purchased.
I shorted the top right 2 terminals on the ALDL and turned the switch on.
All i got was 1 blink, then 2 over and over again.
Am I correct that this means no codes present?
The strange thing is that when the terminals are shorted and the switch is on, It sounds like the radiator fan is running. Is this normal?
When I pull out the paperclip and turn on the switch, the fan is off.
I didn't want to proceed until getting some expert advice.
Thanks,
Scott
I'm trying to correct using info found here.
1990 C4, 31k miles, near showroom condition. Recently purchased.
I shorted the top right 2 terminals on the ALDL and turned the switch on.
All i got was 1 blink, then 2 over and over again.
Am I correct that this means no codes present?
The strange thing is that when the terminals are shorted and the switch is on, It sounds like the radiator fan is running. Is this normal?
When I pull out the paperclip and turn on the switch, the fan is off.
I didn't want to proceed until getting some expert advice.
Thanks,
Scott
Drifting
Joined: Apr 2020
Posts: 1,925
Likes: 610
From: Orange, CA
https://tech.corvettecentral.com/201...trouble-codes/
The top right terminals are not the correct terminals to jumper.
The top right terminals are not the correct terminals to jumper.
Thread Starter
7th Gear
Joined: Nov 2020
Posts: 7
Likes: 1
From: Augusta, GA
To retrieve SIR (air bag) codes jumper A and K . Top right and bottom 4th from left. The codes flash on the INFT RESTR light. You will probably get codes 16 (LH, under the battery) and / or 26 (RH, under the air cond suitcase). These are the frame sensor codes often associated with bad grounding between the sensor mounting bracket and the frame. Remove the sensor attachment bolt, clean everything well including the bolt and reattach. A toothed washer between the sensor and the frame helps establish a better connection. Everyone says "use dielectric grease". Dilectric grease is an insulator. Not what you want. I use a copper conductive paste. Or a light coating of white grease with the toothed washer works to prevent future corrosion.
Clearing SIR codes is really fussy. It may take a few tries.
When you enter ALDL by shorting A&B, all ECM controlled solenoids and relays are energized. (Except fuel pump). That's why the cooling fans run. Normal.
Clearing SIR codes is really fussy. It may take a few tries.
- Turn key OFF.
- Ground ALDL A to K.
- Turn key to RUN
- Wait for fault codes to begin flashing, unground K for for 3 seconds +/- 1/2 second.
- Ground K again for 3 seconds +/- 1/2 second.
- Unground K and wait 10 seconds. Before turning key OFF, verify that code 12 is the only code being flashed. If not, codes have not been properly cleared. Try agian at step 1.
When you enter ALDL by shorting A&B, all ECM controlled solenoids and relays are energized. (Except fuel pump). That's why the cooling fans run. Normal.
