That was bad advice. I believe Oldblue did that once and fried the radio.

 

Yes, but that was the positive cable touching the ground and the RAP shorted out.

 

Bad advice, but that's what the shop will try first if I take it to them. That's why I asked. I've had two other people tell me that it won't hurt anything as long as the battery is NOT connected. Right now I have no radio anyway. Dead silence for a 40 minute drive is psychologically taxing. The car is too old to replace it. It's not worth it. Still have issues from when the engine was replaced. Fight every year to get it inspected. No one can figure out its issues. Now this to add to the rest.

I'll replace the negative cable this weekend.

OldBlue - was the battery connected when that happened to you?

Thanks,
Jessica

 

Fight to get inspection?

 

I got siriusxm and use my cell phone. much better tunes and no commercials. I then switched to my HHR and added a bluetooth adapter behind the dash with a cable to the radio. works great and connects whenever I get in the car.

 

yeah it keeps throwing the 455 loose gas cap code. It's not the gas cap. I've replaced vent and purge valves a few times over and it just swaps from the 455 to 446. Been dealing with it since the engine swap. I'm sure it's just a hose clogged somewhere between the gas tank and the rest of the car. LOL
Anyway, I replaced the negative cable to the battery tonight. Before connecting it I disconnected the whole battery and let it sit for about an hour. After I reconnected it all the radio came back like nothing ever happened. Even still had the correct time and all my preset stations. Crazy!
thanks,
Jessica

 

These trucklets have a mind of their own! Glad to see your radio is back up and working.

 

Since it happened after the engine replacement, I would be looking under the hood. Like a loose connection to the EVAP purge valve.
When you replaced the EVAP vent valve did you take care with the gasket?
P0455 is NOT gas cap, it is large EVAP system leak, like the vent valve is not properly seated. P0446 is likewise the vent valve performance, like maybe a loose electrical connection. There is also a fuse #64 under hood.
If this is a 2006 or 2007.there is a adapter needed that could be bad. The natural state of the valve is "open" So, that would read as a large leak.
Could also be the fuel tank pressure sensor being flaky.

Since the engine was replaced It could be those 4 bolts in the fuse box did not get tightened enough.

 

It will tell me the gas cap is loose and then throw the 455 code. I've googled it and watched videos for it. Yes they've checked the seal on the vent valve. It actually throws a 171 code if the seal is not seated properly. I dealt with that one too.
It's a 2011.
Google search result: "The P0455 code on a 2011 Chevy HHR means there's a large leak in the Evaporative Emission (EVAP) system, usually from a loose gas cap, damaged EVAP hoses, a faulty purge valve, or a bad vent solenoid, preventing fuel vapors from being contained and burned, often fixed by checking the gas cap first or replacing the purge valve/hoses, and requires a smoke test for deeper issues."

I watched a video a few weeks ago where he went through replacing the gas cap and the purge and vent valves and then replaced a hose going from the purge valve to the gas tank and that finally solved it. I am going to take it down to the shop and see if it passes with the code anyway. If it doesn't then I will try harder to fix it. LOL I have till the end of February.

Thanks,
Jessica

 

GM issued at least one TSB regarding the evap leak codes, P0442 (small leak) and P0455 (large leak ) Pretty sure I've posted it in the past. I would sum it up as, "Here's a long list of places to look. Good luck "

Both the fuel and evap lines are notorious for corroding above the rear axle. Addressing that is covered in these forums. The purge valve under the hood and evap solenoid valve out back are two common culprits, all well covered in these forums.