Anyone have to deal with a GM PASSlock issue?

[Baz]

My 2002 Silverado 4.8 (241K miles) wouldn't start last Friday, after I stopped for an errand.

I have to admit.....the engine had been exhibiting some sputtering on and off for the couple previous weeks.

I changed the fuel filter out a couple weeks ago and had planned on doing the spark plugs next.

What was odd was the "security" light came on...something I had never seen in 19 years of ownership.

With the help of my mechanic, we ruled out the fuel pump.

The truck is over at his place right now and hopefully he can get it figured out.

Prior to taking it to him, I attempted a couple "fixes" including the "relearn" procedure (turn key on for 10 min., turn off for 10 sec., try to start, repeat 2-3 more times) without any luck. I also tried to bypass the little connector under the clam shell over the ignition switch. Again - no luck.

I did not splice in a resistor, but left one with my mechanic to try.

Thought I'd throw it out to the bird collective for input.

GM went through a number of anti-theft systems. The one for my truck doesn't involve a special key other than just having the right cuts. There's a sensor inside the lock with a magnet and hall sensor thingy, according to what I have read.

TIA for any thoughts....

[A930Rocket]

I’m no help, but good luck.

[Baz]

Originally Posted by A930Rocket

I’m no help, but good luck.

Thank you!

[Brian 162]

Baz
Could it be the key? Does it have a chip in the key?
I’m just guessing

[Baz]

Originally Posted by Brian 162

Baz
Could it be the key? Does it have a chip in the key?
I’m just guessing

No chip, Brian.

Never had one nor needed one. Those were for earlier systems.

Thanks!

[masraum]

Originally Posted by Baz

There's a sensor inside the lock with a magnet and hall sensor thingy, according to what I have read.

TIA for any thoughts....

What's the electronic stuff in the lock for if there's no chip in the key?

[fastfredracing]

I believe I have seen the [pats wires from the ignition switch break on tilt columns more than once in my life .
Do you have a no start, no crank condition ? Or does it start for a second then die ?

[john70t]

Originally Posted by Baz

With the help of my mechanic, we ruled out the fuel pump.

(scattering the cards on the table here, to start over from scratch, if it wasn't confusing enough)

If he jumpered the fuel pump directly that doesn't discard a blocked line at the tank, bad or intermittent FP relay/fuse, whatever controls the pulses (PCM? ECM?), or ASD(auto shut down) relay mentioned by Fred in another post.

Once had a Bosch relay on a '89 Golf that would overheat with random heat soak after stopping. Or it would not start randomly. Probably a worn pump was drawing too much current. A new FP relay fixed it.

The vehicle might have a bad park/neutral lock-out switch. Or brake switch which releases it. My '95 Subaru would only start in neutral and had to open up the console for the manual shift lock.
Wiggling it sometimes helped.

Another possibility is a bad crank and/or cam sensor. That is another signal required for the engine to start running.

A quality scan tool would show a lot. Especially any codes.

If you can get some "noid lights" at harbor freight if might cut down the diagnosing. Put one on a disconnected injector. They flash while cranking. That means the crank/cam sensor is good, ECM/PCM is good, and it's trying to spray gas. We will assume the timing is correct and not a factor. It would at least burp and sputter.
Then it's off to hunting down spark and actual fuel delivery.

[Baz]

Originally Posted by masraum

What's the electronic stuff in the lock for if there's no chip in the key?

It's not part of the key. It's part of the ignition switch.

[Baz]

Originally Posted by fastfredracing

I believe I have seen the [pats wires from the ignition switch break on tilt columns more than once in my life .
Do you have a no start, no crank condition ? Or does it start for a second then die ?

The last one, Fred. Engine turns over. Tries to start (1 second's worth) - but doesn't.

Gotta get that clam shell off to get a better look. That one screw wasn't coming out. May end up prying it off.

This article explains some of this:
https://www.locksmithledger.com/keys-tools/article/10238356/general-motors-vehicles-equipped-with-passlock

My mechanic is very sick right now - went to the hospital today to get checked out. I hope he gets better soon. He's a good guy. His son works there too but is slammed. I'm just seeing if anyone else went through the same thing and how they resolved things.

I will check for a pinched wire, Fred, as soon as I can get that damn clam shell off!

Thanks, all. Will keep you posted if I make any progress.....

[Baz]

Originally Posted by john70t

(scattering the cards on the table here, to start over from scratch, if it wasn't confusing enough)

If he jumpered the fuel pump directly that doesn't discard a blocked line at the tank, bad or intermittent FP relay/fuse, whatever controls the pulses (PCM? ECM?), or ASD(auto shut down) relay mentioned by Fred in another post.

Once had a Bosch relay on a '89 Golf that would overheat with random heat soak after stopping. Or it would not start randomly. Probably a worn pump was drawing too much current. A new FP relay fixed it.

The vehicle might have a bad park/neutral lock-out switch. Or brake switch which releases it. My '95 Subaru would only start in neutral and had to open up the console for the manual shift lock.
Wiggling it sometimes helped.

Another possibility is a bad crank and/or cam sensor. That is another signal required for the engine to start running.

A quality scan tool would show a lot. Especially any codes.

If you can get some "noid lights" at harbor freight if might cut down the diagnosing. Put one on a disconnected injector. They flash while cranking. That means the crank/cam sensor is good, ECM/PCM is good, and it's trying to spray gas. We will assume the timing is correct and not a factor. It would at least burp and sputter.
Then it's off to hunting down spark and actual fuel delivery.

Thanks, John....good suggestions and will keep in mind!

[Tishabet]

Have you tried getting an OBDII reading? My money is on the "TBC" fuse in your panel under the hood being blown.

[john70t]

Originally Posted by Baz

My 2002 Silverado 4.8 (241K miles) wouldn't start last Friday, after I stopped for an errand.

I have to admit.....the engine had been exhibiting some sputtering on and off for the couple previous weeks.

A distributor cap vs. coil-over-plug makes a big difference.
If one c-o-p goes bad, it should still start or run a little worse.
Something that affects the entire system, you got to start swimming upstream to the source.

Narrow it down:
-A clogged cat/muffler will at least start and run for a few seconds or minutes.
-Does the tailpipe smell like gas? Then it's probably spark.
-Air filter okay? Might still be a TPS or MAF/MAP sensor which tricks the ECU into not giving gas.

I have no idea how a GM Security lockout works(spark or fuel) or what triggers it.
Might even call a more distant dealership or search internet forums.

If the key has an RFID but the corresponding ignition sensor goes bad, that might do it.

[Brian 162]

Have you tried YouTube? It’s bailed me out a couple of times.

[john70t]

I didn't see any common complaints or recalls here specifically, with a brief search: https://www.carcomplaints.com/Chevrolet/Silverado/2002/engine/

Might have missed something.
It might be the security system, or something failed triggering it?

[Baz]

Thanks all.....my mechanic is back at work on the truck and I will be visiting him tomorrow to catch up with his latest thoughts.

Hoping it's something small and just needs to be ferreted out.

I tried my OBDII, Grant and it didn't reveal anything. Maybe my mechanic has a better version.....

[Baz]

I've been using my Volvo to get by while waiting to get my truck going again.......











Buddy of mine with a Taco has been out of the country for the past week and just got back so I'll be able to borrow his unit this week as needed.

[thingmon]

Volvo seems to be doing fine…

[thingmon]

Redundancy is good!

Dave.

[A930Rocket]

I’m not sure which part It is, but it’s the one that tells the fuel pump to run, after the initial start…. ECU or ECM?