Chevrolet Cars & Trucks - Answered Questions & Fixed Issues
How to remove air pockets in the cooling system.
When you have air in your cooling system, check for leaking gaskets. Most of the time the head gasket is leaking. and it is just a matter of time the whole gasket blows out. It will cost you because the engine needs revision, once the head gasket blows. Don't drive till a tech has checked your engine.
17 hours ago
Not enough data in computer for emissions testing
Has the battery been disconnected, or has it gone dead? Every time the battery is disconnected, all trouble codes are cleared, the check engine light is turned off, and all system monitors are reset. For the monitors to get back to a 'ready' status, the vehicle needs to go through one or more (sometimes quite a few) drive cycles.
When you go to the emission station, they check for codes, AND also check to see how many of your monitors are in a 'ready' status. (This keeps people from disconnecting the battery, and thus clearing any trouble codes, in order to pass emission tests).
If you have not disconnected your battery for a while, but the monitors are still not showing 'ready', you need to have a qualified shop check out your computer and other electronic systems.
GM Delco Radio unlock code
There are 2 types of GM Theftlock, Theftlock I and Theftlock II.
The Theftlock I is found in pre 2000 vehicles and Theftlock II is
in the latter models.
Theftlock I - Uses a volatile code that is input through the key
pad on the front of the Radio. If the power is lost (dead battery
etc.) the code is gone and must be re-entered for the radio to
If you do not have the code, you can get it by phone, email, etc.
but you will need the 6 digit Radio ID number.
To get that, just turn on the ignition and hold down the 2-3 keys
(sometimes 1-4) and the first 3 digits will appear in the display.
Then hold down the AM/FM button and the last 3 digits will
With this number you can get the unlock code. This code is
available all over the place for less then $10.00. Just search
on theftlock. Use the HR and MIN buttons to enter the code
and you are in business.
This may sound a bit complicated at first but you can do it
in less then a minute with a little practice.
Theftlock II - Uses an EPROM (erasable/programmable
read only memory) or a PROM (the difference is you can
not alter the prom once it is programmed). In either case
the code is burned in and holds even when the power is lost.
With Theftlock II the radio is married to the vehicle by way
of the VIN. When the vehicle is started the computer
compares the number in the radio with the VIN. If they
match, the radio works, if not the radio displays LOC and
you are finished, there is no easy way around it. The radio
will not work until you make a trip to the dealer.
If the radio has an EPROM the dealer will use something called
a TECH 2 DEVICE to change the VIN stored in the Radio.
The Radio does not need to be removed (for the serial
number or any other nonsense). The technician just plugs
into the computer and resets the VIN in the radio. It can
be done (if you know how) in less then 15 minutes.
I checked around and the going rate is about $60.00
(none of the dealers I contacted would do it for free).
That works out to $240.00 per hour, but still much
cheaper then a new GM Radio.
If the radio has a PROM then the chip must be changed
and that seems to be factory only, in other words a new
radio! The good news is, only a very few of the high end
GM vehicles are equipped with a PROM so it is highly
unlikely that your radio has this anti theft feature.
My 2008 chevt hhr is having intermittent starting problems. The Passcode 3 system is in the car. The anti theft light came on 3 weeks ago then shut off.
DUring those periods when it doesn't start, does the security light flash? If so, there's a trouble code stored. Also, GM has issued a service bulletin advising you to remove all other electronic devices from the vehicle before starting anti-theft diagnosis. That means removing phone charges, dash cams, even extra transpoder keys from your key ring.
Also, BTW, thanks for not telling us the year, make, model. we know it's a national security secret, but it help technicians to know what vehicle you're asking about.
2 days ago
My rear brakes are getting way too hot on my 2000
This year of truck did have issues with rear disc brakes. Quality of pads is extremely critical. Go with the AC Delco pads and rotors to eleviate some of the issue. Make sure that the slide pins are liberally lubricated and move freely or drag will cause excessive heat to occur. Let me know if you need anything else.
on Nov 08, 2019
Not finding what you are looking for?