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No start problem

PassLock System Will Disable The Fuel Injectors And Crank Relay For Ten Minutes.

When the security system detects (correctly or incorrectly) somebody trying to steal the car, the car won’t crank and won’t get fuel.

I am looking in my 2001 Impala Factory Service Manual Volume 3 of 3. "The ignition key turns the lock cylinder. The cylinder rotation produces an analog code in the Passlock sensor. The voltage code is received by the BCM. The BCM compares the voltage code to the previosly learned voltage code. If the codes match, a class 2 message is sent from the BCM to the powertrain control module (PCM). The message enables the fuel injectors and the crank relay.


Old School, I Think You Have It Wrong.

The mistake you are making is possibly in thinking this is “Passlock 2” when it is the original “Passlock” security system. I don’t think you are connecting the dots from the correct model year of vehicles, perhaps. Our car and manual that are both here, are both 2001 Impala. Give me the Bar code number (back cover) of your manual and I’d be happy to check it for you.

You are correct in thinking these are both Passlock systems (no chip in key), but you must have the wrong year or model that use Passlock 2 or are making another error of some kind. Please see my post, farther on down.


I can’t give you a definite answer, but I think it is a good chance a new starting motor will solve your starting problem.

Since the problem is intermittent it is proving very difficult to diagnose with any certainty. Here are your options as I see it;

You can live with it until one day is dosen’t start at all.

You can leave it with your mechanic to drive until the problem occurs to him and then perhaps he can make a firm diagnosis.

You can replace the starter and see what happens.

Them’s the choices.

i have left it with him and everytime he has it the dumb thing starts.
but i am willing to try anything right now so i will see if i can fine someone to put a starter on it. i will keep my fingers crossed that it will fix the problem. i also do meals on wheels which is alot of stops but for the last couple of months i do not turn off the car because worried it will not start back up. so maybe it could be the starter.

In fact the data I am giving is for PassLock (it is out of a 98 FSM)But what I am concluding is that the 2001 has PassLock2 but standard PassLock tests apply.

So the mistake I may be making is diagnosing the car with Passlock data when it is infact PassLock2.

Let me see if my AARC data base hookup clears it up.

As it turns out the car should have the PassKey3 system,Let me see what I can come up with (I found a description of a 2000 Impala and it was said to be equipped with a PassKey 3 system)

Old School, This 01 Has A Pass Lock System, Not Pass Key, No Key Transponder Chip.


Fine I will go on to other issues. In any case neither PassLock nor PassLock2 disable the starter they disable the fuel.

Do you know the features of PassKey3? and what models it was installed in.The first vehicle I see equipped with PassKey3 is the 99 Venture.

OK the data base that listed the 2001 as having PassKey3(chip in key) was wrong,the 2001 does have Passlock2,85% of Passlock2 failures will still crank but some even fail to crank. I verified my info by telephone call to a Canadian car security firm,the guy told me GM used Passlock,Passlock2 and Passkey3 all at the same time,just vehicle dependent,no wonder things get messed up.

I Doubt This Is A Starter Motor / Solenoid Problem.

I wouldn’t waste money replacing the starter without verification. That is not sound diagnosis.

You could do a couple of things. Is this a 3.8? I know the starter is in front and you could hook up a temporary light to the starter that would illuminate when the key is in the start position. I’d tape it up near the rear of the hood by the wipers where you could see it from the driver’s seat. When the car fails to start, you can see if that light is still illuminating. If it does, but the car won’t crank, it’s probably a starter problem.

Otherwise, you could do what people with starters going bad have done for generations. When it won’t crank, keep bumping the key to start and try to rock the starter into action. However, again I don’t think this is a starter problem and I’ll bet if somebody listens very carefully when it won’t crank, they’d never hear any sound from the solenoid.


Just so you know I hear you and have been corrected in my denial of designed in starter interupt but what you write does not specificaly say that PassLock activation disables the relay, it just says the message enables the crank relay.

It is just that with in my contacts today with companys that build modules to get around the PassLock system no one is mentioning a designed in starter disable feature.

One thing for sure you can’t assume that because one model year is using a certain version that another model of the same year is using the same version.

CSA please don’t take my responding as arguing I am just exploring what is going on and my goal is to help the people with problems not to prove a technical point.

I worked with PassLock2 mainly with the Malibu around 1998 and I do remember the starting and dying sympton. I must remember not to relate my experience with the Malibu to how the Impala is designed.

Old School, I Understand. I have Even Read About Certain Vehicles Cranking And Starting And Then Being Disabled By The Pass Lock Or Pass Key Security.

My son has a 2001 Impala. He has Passlock with no chip in the key, only tiny sensors in the ignition switch. In two years the security system has “hibernated” for ten minutes only 2 or 3 times. The first time it did this I was tempted to replace the starter and studying a bit more, the ignition switch. I’m actually glad I didn’t do anything. Most of these vehicles do not crank, dash lights work and all, but no crank, no click, nothing. I was on location one time it did this and it was dead. Ten minutes later it cranked and fired and ran.

I have a GM Guru who told me to first try a key cut from code. The ignition switch was next. I have done nothing and it seems to have recovered for months now.

I see on the web that some guy claims to have solved the mystery. He claims that the connector at the ignition switch fits poorly and after some time corrosion gets in. He claims he examined it with a microscope and says that the connections should have been gold plated the way some connections in electronics are. He claims to have fixed his problem by soldering the wires directly with no connector. This seems feasible as many people claim the problem is exacerbated by changes in weather.

What say you?


I say I found many companys selling “defeat” type modules for all types of GM security systems and read reports of repeated replacement of various components of the system. I conclude it is best to go around this problematic group of systems as it does not seem one fix fits all.

I’ve read your communique regarding the “start-when-it-wants-to” problem people are having. I’m having it too with a 1999 Olds Cutlass. It is extremely frustrating. I get in my car 1 hour early for work, just to make sure the car will start so that I can get to work on time. This car’s anti-theft system is linked to the fuel injection!!! I’ve changed the starter, intake manifold, you name it, I’ve probably had it done. I’m considering the Alarmtek by-pass kit for the Passlock II system. However, in the discussion I referenced earlier (2001 Impala, I think it was – Waldok7810). Someone in that discussion mentioned sautering the wires together. I would like to communicate with the person that made that suggestion to see how it’s working for him or her, the model/make and year of the car, and exactly which wires.

The tow services are going to think I’m crying wolf and aren’t going to show up when the anti-theft system finally dies! HELP!!!

ok i first started with a complait to gm and they sent me to this wed site on other complaits with the same problem and someone e-mail me back with this step to bypass the passlock:

On top of the ignition switch there are three thin wires with black friction
tape covering. The wires are black, yellow, and white. Cut the yellow wire in
two. Strip the insulation from the middle of the black wire but do not cut the
wire. Place the red clip from a multi-tester on the yellow lead going to the
ignition switch. Place the black clip on the bare section of the black lead.
Try to start the car and read the resistance (mine is 557 ohms). Go to Radio
Shack and get as close as you can get. I placed a 220 and 330 in series.
Solder the resistor(s) between the bare section of black wire and the yellow
lead that does not go to the ignition switch. Tape everything up and you should
be good to go.

This is on a 2000 Malibu. I can’t be sure that all are the same colors and

now i had someone try this on my car but could not get it to work so not sure if he did something wrong or what he just put the car back together an i am still having the same problem. i just really need to find someone that will really look at it that knows what they are doing and not charge me an arm and leg. so now i have sent a letter to gm again.

here is also the response i received back when i filed my first complaint.

Hello Kathy, thanks for adding the electrical complaint with your 2001 Chevrolet
Impala LX - it’s been added to! Click on the link below to
view your complaint:

This is a widespread problem with the Passlock 1 and 2 anti-theft systems on
virtually every GM model made from the late 90s into the mid-2000s. Here is the
list of complaints we have for this:

Also there is a website about how you can bypass the security system instead of
spending $400+ on a repair that may not work, see the link below:

If you find out what the problem is, you can update all your complaint
information here:

When you experience any other problems with your Impala, please remember to come
back & add them using the Add Complaint form:

Thanks again,

you would think if they know this is a wide spread problem that someone would know how to fix the problem or at least do a recall for the problem!!!

Recalls Are For Safety Related Problems. The Safetst Cars Are Ones That Cannot Be Driven.



I don’t know anything about the PATS system really but I have been reading the posts here and saw the schematics that Autozone has and Hellokit so nicely provided a link to. As I was looking at the drawings I see there is a indicator light for the security system and assume it is in the dash. I was wondering if this light turns on or changes indication somehow if the security system gets activated and then prevents the car from being started even though the correct key is installed. If there was some sort of indication of that it may help determine if the security system is at fault or something more simple is causing the trouble.

From what I have read about this here, the problem is the engine intermittently doesn’t crank when this trouble occurs and we have not verified if other things like the ignition system and fuel pump are working. Do I have the story right?

no the security light does not come on only when the car will not start and i have to turn the key to on position for 10mins and than the light will flash. than after 10min i turn the key off take it out 1min put the key back in and than the car may start.

well i wrote another bitch letter to gm and i just got a call from them and they want me to take the car to a dealer in the morning to run a test on it and then they are suppose to call me back with answer on what they found out. even thought i was charged for that same test when they put in the new BMC or BCM (what ever it is called) will let you all know what i find out!!!

Sounds Good. Thanks. BCM = Body Control Module.


Well if the security light isn’t activating that makes me thing the trouble is somewhere else. But then, I am not positive the light will show up if the system has a fault.