2005 Pontiac Grand Prix Engine Throttle Shutdown/Reduced Engine Power

Driving on the highway a month ago, my 05 Grand Prix just shut down. A message came on the OBD that read "engine throttle electric shutdown" or something similar and then "reduced engine power". It turned over after a second key turn with 3 clicks and I drove away. I investigated on this site, and had my throttle body thoroughly cleaned out as well as the fuel injection system. The car was good for a week and it did it again and I took it to a repair shop and had a diagnostic run on the car. No codes, so the mechanic drove it and it did it to him. He then put it on the machine and 10-12 codes came up after it shut off a second time in the garage. He said that was impossible for all those failures to happen at one time. He pulled a GM service bulletin that identifed corrosion on the grounding wire as a possible cause. He cleaned it and the car shut down the next day. I started to think, this was happening with the air conditioning on. I've had the air conditioning off, and the car has been driving fine without the check engine light coming on or any shut downs. For many years, the car had the check engine light on and it kept throwing the "catalyst below efficiency" code, and I refused to replace the catalytic converter, while at times the car would hesitate when a I pressed the pedal after 10-20 mph. That same technician said nothing was wrong with my converter. He thought the ECM might be bad or going bad. Any thoughts? Thanks.

your symptoms sound like a bad crank sensor. if you noticed that the tach dropped to zero and then died, it for sure the crank sensor.

Thanks. I will check that out.

that sensor is also famous for not throwing a code either.

Thanks again. If I do not turn on the air conditioning(condenser) will that help prevent the car from shutting down?

a/c should have no affect on the car shutting down. may have just been coincidences that it was on, or you turned it on.



****unless the compressor clutch is shot and sizing up, then yes it can stop your engine form running. is you a/c making more noise than it used to?

There's a weezy sound that is made while the a/c is on and I'm at a light.

from under the hood or in the dash? like the fan or something?

if the compressor is going bad it will knock your idle rmp's down for sure. as soon as you turn it on.

At times, I've heard a whining sound from the dash when I've accelerated, like a fan or something. Haven't heard that in a while. I do hear a whining sound from under the hood as well.

the a/c will make some noise when its on. thats normal. and it sounds like your fan is making noise. its behind the glove box.