Vats code 46
Thread Starter
Intermediate
Joined: Jul 2024
Posts: 36
Likes: 0
Vats code 46
Alright so I know that it’s a vat’s malfunction and my no crank no start, but since it’s a 1990 corvette the vats is programmed into the ecm. I don’t own a fsm for my vette yet, anyone with some knowledge is greatly appreciated.
Safety Car
Joined: Jun 2010
Posts: 4,564
Likes: 1,676
If you have a second key, try that first.
But basically code 46 the CCM and ECM are not communicating on circuit 229
Team Owner
Joined: Sep 2003
Posts: 25,365
Likes: 2,731
If you have the car titled, you can take the registration or title + corresponding personal ID to a GM dealer and ask that they do what's called a 'Key Call'. For a '90 I believe it would include original key numbers and also the code for the 'resistance'. Dealers will NOT do it without ID and they do generally charge for it. If the key cylinder has ever been replaced then that key code wouldn't work but 'very seldom' is the 'resistance' ever changed. I believe you could rely on the resistance. To confirm the key code have them or a locksmith cut a brass 'work key' and confirm rotation before doing a resistance key.
Thread Starter
Intermediate
Joined: Jul 2024
Posts: 36
Likes: 0
If you have the car titled, you can take the registration or title + corresponding personal ID to a GM dealer and ask that they do what's called a 'Key Call'. For a '90 I believe it would include original key numbers and also the code for the 'resistance'. Dealers will NOT do it without ID and they do generally charge for it. If the key cylinder has ever been replaced then that key code wouldn't work but 'very seldom' is the 'resistance' ever changed. I believe you could rely on the resistance. To confirm the key code have them or a locksmith cut a brass 'work key' and confirm rotation before doing a resistance key.
Thread Starter
Intermediate
Joined: Jul 2024
Posts: 36
Likes: 0
Team Owner
Joined: Sep 2003
Posts: 25,365
Likes: 2,731
If you changed the cylinder it would have come with a 'work key' to only rotate and you should have had a new resistance key cut to that mechanical cut. Are you still just trying the key that came with it? Do you have your old key still? If you can measure the resiatance of the old key get a new key cut to match the mechanical of the new and the resistance value of the old.
Thread Starter
Intermediate
Joined: Jul 2024
Posts: 36
Likes: 0
If you changed the cylinder it would have come with a 'work key' to only rotate and you should have had a new resistance key cut to that mechanical cut. Are you still just trying the key that came with it? Do you have your old key still? If you can measure the resiatance of the old key get a new key cut to match the mechanical of the new and the resistance value of the old.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Team Owner
Joined: Sep 2003
Posts: 25,365
Likes: 2,731
If it ran previously(with old cylinder) then either the connector at the steering column base isn't connected, you've torn the wires to the bottom of the column while routing them OR a bad resistance key. Was this a 'For Hire' repair or a DIY?
Thread Starter
Intermediate
Joined: Jul 2024
Posts: 36
Likes: 0
DIY, I inspected the column before and after, shouldn’t have any torn wires and my cylinder is connected properly.
Team Owner
Joined: Sep 2003
Posts: 25,365
Likes: 2,731
Use a resistor to bypass if that works. How did you determine the key resistance you used was correct? Do you have the old key(s) still? Use that key in the 'loaner' cylinder!
Thread Starter
Intermediate
Joined: Jul 2024
Posts: 36
Likes: 0
If you bought your cylinder 'local' ask them to maybe loan you for diagnostics another. Connect the 'loaner' to the connector at the base of the column, insert a known good resistance key in the cylinder and use the key in the column now for crank. That's a very simple bypass for testing. If a tourist had an issue in the past we would suggest this vs a steering column disassembly to do a repair if their pockets were light! The 'loaner' doesn't need to rotate it just need to provide the resistance through the connector.
Team Owner
Joined: Sep 2003
Posts: 25,365
Likes: 2,731
Thread Starter
Intermediate
Joined: Jul 2024
Posts: 36
Likes: 0
Do you still have the old cylinder? If the wires aren't torn or an issue you could check the resistance of the connection with a meter. You could try that. Check the resistance of the key using the wires at the base of the column. How do you know you had a correct key resistance cut?
Safety Car
Joined: Jun 2010
Posts: 4,564
Likes: 1,676
Thread Starter
Intermediate
Joined: Jul 2024
Posts: 36
Likes: 0
Corvettes aren’t new to me but the c4 vats is very new to me
it ran previously but it wasn’t reading the keys resistance correctly triggering vats so i replaced the cylinder. Prior to replacing the cylinder I had one good start pulled it into my garage then it went dormant, no crank no start. That’s when I changed my ignition cylinder. Prior to this code I had the active code where the injectors weren’t getting the signal to pulse but now it’s the VATS malfunction.