Ray Quayle

That TSB was superceded, by 88-292 if anyone is interested.

joe paco

I respect your experience, and mine is limted to pre HEI models, but have read many websites and threads where others claim that the vats will allow crank but CCM will not send the 5v signal to ecm to enable injectors.

Some have argued that VATS shut down a running engine -after the intitial 3 secs or so.

I believe that a healthy suspicion of computers is not a bad thing, but I notice that many people get hung up on one solution to every problem. The OP wondered about the VATS codes being set, more so than how to diagnose the no start.

In 4 yrs, I have had no vats codes, because I never armed the security system. One could still have issues with the PASS key, though.

From my observations, the vats was not well-conceived, nor was it well designed to make it useful and easy for the tech to figure out.

joe

3D87C4

But at this point I'm curious what's up with the old key. The car would pretty consistantly crank but not start with the old, worn, key (with a valid pellet resistance) but has started regularly with my other key and another new key I just had cut. It was bad enough a mechanic replaced the fuel pump trying to fix it. I'd like to know if I can reproduce that problem & see what it looks like from a code/scanner point of view.

Until the "real" problem goes from intermittent to a hard fault it's going to be tough to diagnose.

In the meantime, there's no harm in puttering with the old key and scanner for half an hour this weekend. Heck, I'm even thinking of disabling the resistor in one of my keys to intentionally trigger a true VATS violation just to see it for my own eyes. Tape would do it but I'm afraid some might get stuck in the lock so may just remove the pellet with a hammer.

Thanks for your comments. Rest assured I'm not clinging irrationally to a false conclusion---the symptom table is pretty clear.

3D87C4

Thanks.

I double checked my VIN & my car is within the affected population (and I have the old, short, keys).

If this problem triggers a normal---no crank/no start, code 46 set---VATS violation then it likely doesn't apply.

One other reason I'm interested in this is it's one issue that might survive my proposed engine swap.

3D87C4

So for grins I tried the following experiment this morning (see the datamaster screen shot below):

First I attempted to replicate the starting problem with the old key. Three tries, three starts. Clearly the old key isn't as bad as had been reported.

Next, I wrapped tape around the key covering both sides of the resistor pellet and tried to start the car. The starter cranked and the ignition caught briefly---see the RPM blip at about 11:04---but ultimately wouldn't start. No code saved.

Attempted to start again with the taped key: Crank but no start, no code.

Attempted to start again with the key I normally use: crank but no start, no code.

Waited 5 minutes. Pet cat as he hopped in the open back hatch and made a tour of the car. Car started with key I normally use.

I'm not sure what to make of this, as it seems to contradict the FSM diagnostic table.




The dark blue line above is knock count. Is it normal for the knock sensor to be triggered when shutting down the engine?

P.S. yes, the image above has the time marker at the beginning of the datalog, so doesn't show the final code status. I just re-opened the datamaster file and moved the time marker to the end and can assure you no codes are stored.

P.P.S. What the heck, here's a screen shot with the time mark at the end:

stoydido

not sure what the hell this is! cranks with the resistors taped? not supposed to. you didn't tape all of them, or did you? don't recall if someone had attempted a bypass -I read so many I get lost- but that would explain it.

since you the man with the scanner, you can explain it.

3D87C4

I can only speculate at this point. If I take the FSM literally, crank-but-no-start can't be VATS, but the time-out behavior suggests otherwise. My guess regarding the engine trying to start with the pellet taped is that maybe one of the relays or some other component is reacting slowly to the VATS violation allowing the engine to fire briefly. Or it could be a wiring or key-cylinder issue responding to some subtle variation in the way I was holding the key while it cranked.

It is highly unlikely VATS was disabled, though it might have been done without the PO's knowledge. I'll ask about that, I owe the folks a call anyway.

There might be a clue in the scan, but short of the code and VATS-fail fields I'm not sure what else to look for---I'm a new Datamaster user. Suggestions anyone?

3D87C4

While mulling over yesterday's little experiment I remembered something I'd read in the FSM:

So maybe having the scanner attached to the ALDL prevented any codes being stored?

To check this I repeated the experiment with nothing connected to the ALDL port, scanning after each start attempt to check for codes:

• Two start attempts with the "bad" key yielded successful starts
  
• With scotch tape over the resistor pellet the engine cranked, fired briefly, but would not run---two times in a row. No codes were set.
  
• Attempting to start with a known good key less than a minute after the taped key try yielded the same thing---the engine cranked, fired briefly but would not run, no codes.
  
• After waiting 5 or 6 minutes it started normally using the known good key.

Conclusions?

• The "bad" key probably isn't bad.
  
• The lack of codes does not appear to be caused by a scanner (actually Moates adaptor & Datamaster software) attached to the ALDL connector.
  
• I'm confused

3D87C4

Ok...spent the rest of the day doing sudoku's, laundry, practicing fiddle, napping & grocery shopping. About an hour ago I woke up and started looking through the electrical diagnosis suppliment and realized, once again, I was starting in the middle---I needed to do the System Check before going to the System Diagnosis table.

The System Check begins with trying to start the car. If it doesn't start then you go to the System Diagnosis table.

If it does start (and mine does) then you open the hush pannel under the steering column and disconnect connector C281 (surprisingly difficult to do) and try starting again---the engine shouldn't crank. If it does crank then go to the starter enable relay test.

Next you re-connect C281 and try to start within two minutes of previous attempt. The engine shouldn't crank & if it does replace the VATS decoder module.

So I pulled the connector and the engine cranks. I reconnected the connector and it still cranks. I stared at the schematic for a while and realised---that's exactly the same as taping the key!!!!! Grrrr...lesson: think first before futzing with hard to disconnect connectors.

So here's where things stand:

The system check & taped key experiment suggest either the starter enable relay has a problem, there's a short on circuit 965 (dark green wire) or a problem in the starter enable portion of the VATS decoder module.

The System Check says nothing about code 46 so, though it doesn't say this explicitely, I don't think a bad key pellet read alone will trigger a code. (Please correct me if I'm wrong.)

I believe that my occasional starting difficulties are exactly what I originally thought, misreads of the key resistor due to incorrect positioning of the key, or dirt, or who knows what, triggering the VATS system. The fact that my car cranks indicates a problem with the starter relay or VATS module but doesn't otherwise cause any trouble.

So I think I'm done for now. I'll persue it further if it becomes a hard fault. Otherwise, I have no desire to go digging into the dash to get at the starter relay and/or VATS module just to satisfy my curiosity.

Thank you for your attention.

Cliff Harris

It sure sounds like your starter enable relay is bad or has been bypassed.

As you saw in the FSM, it shouldn't crank with a taped key.

I just checked the ECM program, and there are three ways to get a VATS error (Error 46). No pulses from the VATS module, VATS pulse frequency higher than 40 Hz, VATS pulse frequency lower than 20 Hz. It uses the same error code for all three problems, which means there is no way to tell which one caused the failure.

3D87C4

I agree the relay is the most likely fault. Since it has failed in the "starter enabled" state and the fuel control part of the VATS remains functional there's no compelling reason to fix it at this time (though I may ask my mechanic what he'd charge to do it when I get the oil changed this week).

So, since you can read the ECM program, am I correct in concluding a bad resistor read alone won't set a code? The lack of a code is what triggered this whole thread.

Thanks

Cliff Harris

The VATS module reads the resistor in the key. It doesn't really communicate with the ECM except to send a 30 Hz signal to tell it that it read the key correctly. The ECM checks for that signal when you turn on the ignition. If the signal is missing or the wrong frequency it sets Code 46.