Hello all,

Recently picked up a '91 automatic trans (my first Vette ever) started having problems with the car not starting and also the security system light would stay on when the doors were locked. The door ajar light is also on and my courtesy lights are on as well. Read here that more likley than not it's the VATS. So I bypassed the system just like the instructions said and the car started right up....but...the security light is still on solid not blinking when the key is removed. Tried starting her up again and nada..dead in the water. Had to tow the car home for the second time in three days and now it's sits in my garage. Could it be the neuteral safety switch? The reason I ask is that I tried to start it yesterday and no go....I put the car in gear and worked it in each gear all the way to first. When I reached first the indicator line was between second and first and I noticed that the console kinda moved a bit with it. I put it back in park and tried again, this time it went all the way to first and the indicator line was now right over first. I then put it in park and she fired up. Took it to my bud's house and we did the bypass..she fired right back up...turned her off and tried to start it and nothin. Messed with the gears again and still nothin...that's when the tow strap came out once again. Not sure what to do here short of getting her to a mechanic but am having a real hard time finding any who know how to work on a Vette around here. Called the Chevy dealer and the "service manager" didn't know his head from his @$% and said he would get with a tech and call me back. No call yet from the dealer believe it or not. Any help or suggestions would be welcomed. Thanks everyone.

 

the neutral switch operates in neutral and park, no need to go thru gears 'cause it won't start in gear.
how did you bypass the key -from what instructions? if done properly that eliminates the key itself, not the decoder or other parts of vats.

lights are on when key is off? door open, key off, the security light should blink. will stay on if power locked. for starters, don't use power locks.

security light on solid is a code 51, key decoder or key issue. what codes are in the ecm and ccm?
I assume that "nothing" means exactly that -no lights dim, no relays click, etc. meaning the ign switch is not sending current, or it is not reaching starter solenoid. if key/bypass resistors are not matching what is stored, ecm disables start relay and fi enable circuit, as you know.

it is possible that the resistors you installed are outside the decoder's value, maybe left the key reader in, whatever.

need to understand exactly how you bypassed it. I know how it is supposed to work.

joe

 

Hi Joe,

Thanks for the reply. I got the instructions from one of the forums on this site. Used a mulitmeter to measure the resistance on the pellet and got Key Code 4 (came in at 880)..got a cpl resistors that measured 880 as well. Clipped the connector (2 white wires w/ orange sleeve) above connector going to streering column and lock cylinder. Soldered resistors together and used male/female connectors to complete the loop then plugged back into connector leading to dash.

Courtesy lights stay on when key is off and door adjar light is on...so I think I have a bad door adjar switch (pulled the fuse to eliminate for now). Disassembled door pannel to removed adjar switch and inspected and shot it with compressed air and installed again with same result. Not so much worried about that for now.

Security light remains on when key out and door locked

Don't know codes for ECM or CCM (just got the car cpl weeks ago)

I believe the resistors are within value.

Thanks again,

John

 

there is a procedure for reading codes thru the "assembly line data link", ALDL, connector under the dash. you are not familiar with that? auto zone can read them for you. the deal is to clear them so you can see what is current.

if I follow, your bypass is not still using the harness that attached to the key reader, correct? the 880 is correct, but IF the resistance of the soldered connection is out of tolerance, that MIGHT explain why the decoder in the ccm is not allowing it to start -if that is occurring.

there is a lengthy process in FSM for "no start, no click." it isolates all the components, and finally gets to the VATs.

if you are not using power lock, the security is not armed, should have no light. that issue sounds like a door harness issue or lock, not the "no read" issue. if not the key/resistors, the mechanicals are starter solenoid connection, purple wire itself, neutral swich or two wires, starter relay, ign switch, VATS.

 

Thanks for the response ......checked resistor value before I installed it and got 880 as well (failed to mention that in last reply) then connected it. She fired right up.....with it running security light was off. Turned engine off and security light blinks like it should.....got out and used power lock to lock her up and security light stays on solid and does not go out......tried to fire her up again and it wouldn't start.

Towed it home put in garage and disconnected the battery for the night. Just got home from work and connected the battery and am having exact same issues as yesterday ......no start....security light blinking and then solid when I lock it

I hear ya about autozone but can't get her there. A friend of mine is comin by to test the starter in a bit. Everything was fine until last Saturday night and when we came out of our favorite watering hole this issue began. Just locked her up and drug her home the next morning ....So this is where I'm at

 

got it.

the light should go out when door closes, so that issue may not be related to no start -except that lights and starter relay enable are controlled by Central Control Module.

so you don't spin your wheels, with key in start mode, the purple wire on solenoid should have 12 v. starter itself is not suspect yet. or jump the solenoid terminal to the battery cable lug on starter. if solenoid engages, trouble is back towards the ignition, as I mentioned.

saludos, joe

 

Hi Joe,

Welp took your advice...tested the solenoid as instructed and got 12v...jumped the solenoid as well and it did engage...thinkin I should change out ignition with VATS? What ya think?

Thanks again for all your help

John

 

curious. if the solenoid showed 12v, in START, that's normal when the starter system is working! vats, start relay, neutral switch all working. so, why didn't the solenoid click, or engage without Jumping to the bat lug? sounds like the solenoid is intermittent. "the book" says if you have 12v light -or on the meter- and solenoid does not engage, replace it.

if you really had the energy, you could jump it again until it starts. wheels off the ground, whatever! but, if you follow my logic, from what you describe, there is no problem with the current getting to the solenoid, no vats, etc.

faulty solenoid explains the start/no start. OR- purple wire terminal has 12v but has high resistance with the solenoid bolt.

I would jump it with key in start. if it runs, the problem lies with solenoid or the connection. if you find a flaw in my logic it won't surprise me!

someone else has an opinion, I'm sure.
joe

 

OK here's the latest,

I jumped the ALDL (connected a piece of wire to position A and G on the ALDL) this allowed me to read the codes in the CCM and ECM. I cycled through the process twice to verify all the codes.

CCM Fault Codes
History
25 (courtesy lamp relay coil circut open or short to ground)
53 (Pass Key detection circut open or short to battery)
46 (VATS Error) from ECM I assume

Current
25 (courtesy lamp relay coil circut open or short to ground)
Second time I cycled through I got C12

1.2 (Display CCM Data)

01-0
02-0
03-15
04-0
05-0
06-255 (Pass Key A/D Count) what does A/D stand for (second time I ran it got 68) ?
07-11.3
08-10.7
09-94
10-79
11-100
12-100
13-0
9180123 (computer?)

1.3 (Display CCM input / status)

01-0 (Pass Key not enabled)
02-0
03-0 (Door Key Switch Alarm)
04-1 (Right Door Ajar)---opened and closed door while doing this and it did not read 0
05-1 (Left Door Ajar)--- opened and closed door while doing this and it did not read 0
06-0
07-0
08-0
09-0
10-0
11-0
12-0
13-0
14-0
15-0

1.4

01-1
02-1
03-1
04-1
05-1
06-1
07-1
08-1
09-1
10-1
11-1
12- Not Used
13-1
14-1 (horn went off)

1.7

---
I did not clear the CCM as of yet. Wondering if I should start with the lamp relay switch first off and see if that will solve the courtesy light issue and door ajar issue. Read on here some guy had to used glued pennies on the left door jam just to get his courtesy lights to go off (what the hell) I'm also thinkin that it may be wise to just replace the ignition switch and lock cylinder just to cover my a@# as well.

The car will still not start and the security light is on solid still. Let me know your thoughts when you get the chance.

John

 

veterens vet
fsm begins with the test at the solenoid and works back. if you had 12v, the circuit in between solenoid and key should be ok. Correct? or have I overlooked something obvious?

what is present issue? 'no crankt, no click', or 'cranks, but does not start?'

in 1.3 the pass key in switch will read 0 normally because key is in run mode.

joe

add: in normal opn, door open key removed, security flashes; lock doors with power lock and light stays steady. close door and it goes out. appears that the ccm does not think doors are closed yet. may not be related to no start, though. key on, light is normally off, but should stay on steady IF pass key is not read.

 

Hi Joe,

We checked the solenoid and got 12v and jumped the starter as well. The present issue is "no crank" with key in and on. The security light blinks (stays solid when locked) so this leads me to believe the problem lies in the ignition. I'm thinking of replacing ignition switch with VATS and lock...new key. The reason I say this is because of what you stated in the last reply "light is normally off, but should stay on steady if Pass Key is not read". I also take into account the current CCM fault codes and the History Codes as well. Thanks for hangin in there with me.

John

 

remember: key is now bypassed with resistors.

pass key read and alarm are two different animals. vats/pass key and ign lock are prob not related now that you have the bypass.\

let's communicate again: if you have 12 v at the solenoid, with key in START, the issue is not key, vats, ign switch, wiring, or neutral switch. because that it exactly what all those components are supposed to do -put 12v at the solenoid.


I suggested that the bolt on the solenoid might have high resistance to the purple wire terminal. OR the solenoid is defective. that is what the fsm says, 8a 30-4

classic 'no crank no click" issue. if you can jump the solenoid and the engine runs, vats has not shut off the injectors. the issue still points to the solenoid.

joe

need clarity: if security is on steady with door locked, this is normal. it is SUPPOSED to go out when door is closed, or when ccm sees door closed. if you have a problem with door switches, it won't go out. but that is not the same "security light steady when key is turned to "ON" issue.That is a key read issue.
you can always lock doors manually and that should take care of the security light issue, for now.

if you have 12v at solenoid, key in START, the relay is working. you may not hear it click. I can't hear mine. failure to enage the solenoid when 12v is applied is in the solenoid.

 

You should be able to hear the starter relay clicking when you turn the key to the ON position. The ECM controls it, based on whether or not the VATS test passes. It was in the center cluster behind the status light panel in the earlier cars and was moved to the instrument cluster when the interior was redesigned with the curved dashboard.

A/D stands for Analog to Digital converter (you say "A to D converter"). It takes a DC voltage and converts it to a digital number between 0 and 255. 255 means maxed out in relation to its reference voltage, which is probably 5 volts, but could be 12 volts, depending on how its hooked up. Since it's part of the "pass key" item, it probably refers to measuring the resistance of the pellet in the ignition key. My guess would be that 255 means that its not seeing the resistor pellet (open circuit). I don't know what value it's looking for (it's actually a range of values to allow for tolerances in the parts), so 68 might be OK or might not.

 

Welp...I surrender..waive the white flag and all that. It's in the mechanics hands now and he's going to start at the starter relay and work upstream then down if needed. Evidently a previous owner has been all up in there (lots of wires cut and taped)...uh brother just what I needed...I'm up to 3 hours labor at the moment parts not included yet, but was given the word that this issue will be resolved today. On a positive note he said that my bypass was done correctly (whoopdie f@#$in doo)...guess I have to pay to play but at least it'll be done correctly. Thanks guys very much for all of your support with a newbie like me. I recently retired from the military and this was supposed to be my retirement gift and as they say "ya get what ya pay for"...so with that being said I elected to "pay" for it so I won't run into this issue again and will be able to enjoy my dream gift. Thanks again guys.

John