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Dan, Auto Service Technician
Category: Car
Satisfied Customers: 159
Experience:  master tech
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Chevy HHR Radio once unplugged is dead in the water.

Customer Question

Chevy HHR Radio once unplugged is dead in the water. The dealer blames the aftermarket wiring of course. The owners manual states that once the unit looses power the unit is unoperable. It also states that its VIN coded. Im getting nothing, no display, no chime with the key ect. Any info would be great. Thanks, JAY
Submitted: 10 years ago.
Category: Car
Expert:  Steve replied 10 years ago.


GM uses a security feature called "theftlock" on many of it's audio systems. If the theftlock feature has been enabled on a GM radio, when it loses power it becomes inoperable ("locked") untill a previously programmed in secret code number is XXXXX If the code number is XXXXX the manufacturer has a second code that is programmed in at the factory that will unlock the radio. To obtain this code, you either have to beg or buy it from a GM dealer, or purchase the information from a source such as . If the theftlock feature has been activated, the display will light but will read "lock". Since you state that the display is dead, I assume this is not what you are currently experiencing (but may run into once the radio is enabled to turn on).

If a late model GM radio is removed and installed in another vehicle, it must be programmed to the vehicle using a Vetronix tech-2 scan tool before it will turn on. THe radio has the original vehicle's VIN number programmed into it's memory, and when turned on it compares this to the VIN stored in the vehicle's powertrain control module. If they do not match radio will not turn on. The purpose of this feature is to prevent a thief from stealing your radio and installing it in another car; an inoperable radio is not a very attractive target for theft. All GM dealers and many independent repair shops have a Tech-2 scanner that can enable your radio to operate again; without one there is no way to turn it on again. If the radio's electrical harness in the vehicle is modified or has other aftermarket components connected to it, the radio will not appear on the data bus and will not be able to be programmed with the Tech-2 untill the vehicle wiring is returned to it's original configuration. This may be what your dealer is referring to when he is talking about aftermarket wiring; the system must be in as-manufactured condition for all of the electronics in the vehicle, including the radio, to communicate with each other on the vehicle's data network.

To make your radio work again, any modifications to the vehicle's original wiring may need to be removed to restore data communication between all of the modules. If it still does not operate, you may need to take it to someone with a tech-2 to reprogram the radio to the vehicle.

I hope this is helpful; if so, an accept would be most appreciated! thanks!

Customer: replied 10 years ago.
Reply to Steve7654's Post: I already know this info. The dealer Im dealing with are morons and don't understand what the real problem is. Its there standered awnser for aftermarket. The only wiring is a line converter on the speaker outputs of the radio which are intact and uncut. This should present no problem with operations. The dealer is jumping to conclusions and I don't feel they evern understand what Tech-2 is. I talked to the tech at the dealer for my customer and they were no help at all.

Thanks anyway,
Jay Enge
Assistant Install Manager
Car-fi/Stereo One
Expert:  Steve replied 10 years ago.

You are correct, an accessory attached to the speaker output should not make the radio not power up.

If there is power and ground to the radio, and the display does not light, then the radio itself probably has in internal problem. I would suggest attempting to communicate with it on the bus with a Tech2. If it has power, ground, and dopes not respond on the bus, then the radio needs to be sent to a service center such as H&R radio for repair.

Customer: replied 10 years ago.
I had a new dealer put the tech 2 on the car and their readings indicate that there is not a radio in the car. The customer is being real cool about it and allowed me to install a aftermarket at my expence but Im interested in finding a fix for this radio to reduce my cost on this deal. I don't understand how disconnecting pwr would do this but its GM. Jay
Expert:  Dan replied 10 years ago.
just disconnecting the radio shouldnt cause it to be inop if it came with the vehicle. one start up it reads the vin info if its correct it works if not it will say locked on the radio then you need a tech 2 to set it up. if the radio you installed is not from your original hhr you may need a vci number to get it working why did you pull the radio? it should be under warranty ?

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