Q: Green key light flashing, car wont start.

asked by on

My AC compressor would not accept coolant. My husband put a hot wire to the compressor to force it to take the coolant. Once he filled it, he plugged it back to the normal harness. The compressor kicked on one time and shut down the car. He started it again, but it immediately died, and now won't start back. There is a green key light flashing. The dealer said the PCM was bad, but another mechanic said there were protectors in place that could have blower before the PCM. Help....I don't want to buy a new PCM if I don't need to. Any suggestions???

My car has 70000 miles.

Hello, from what you describe it would appear to me that you may be having an issue with your vehicle’s transponder and key.

The green key light that is flashing is actually not related to AC at all, it is in fact an anti-theft feature meant to protect the vehicle from being stolen. It is usually activated when the computer has detected any tampering with the electrical system, perhaps set off when you jumped the compressor to accept refrigerant.

As the transponder is built into the vehicle’s ignition switch where the key is inserted, it usually requires replacement with the key, and a very specific procedure in order to properly program the key to the vehicle. While this repair will probably not require a replacement PCM, it may require a new key and perhaps ignition switch.

I would recommend trying to manually lock and unlock the driver door, as well as inserting and powering up the vehicle. If these steps do not remedy the issue, I would then recommend having the vehicle serviced by a dealership for a proper diagnosis and any key recalibration/reprogramming that may necessary.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Green key light flashing, car wont start.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Check engine light

Wow... 329,000 miles on your Chevrolet Uplander. Assuming you are still on your original engine, that is a long lived vehicle. If your Check Engine Light is on, YourMechanic will use an electronic code retrieval tool to download the DTC's...

Q: I was driving to work in a lot of rain and my windshield wipers just stopped in the middle of my windshield. Any ideas what it ma

The windshield wiper system uses a small electric motor to move the wiper arms that you see on the windshield. That electric motor is controlled through a switch, relay, fuse, and wiring. One, or more, of those electrical components has...

Q: Deleting past paired devices from Bluetooth HFL

I have two recommendations that you might try in order to resolve this issue. The first is to check in your owner's manual. This manual provides very detailed information about the radio. Typically, the chapter with information on the radio...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...