Mechanic pulled codes P0300,304,305,306 &455. Stated I needed new alternator, belts, etc. Looked up same codes online & no indication of alternator. Would anyone know how these codes relate to alternator trouble? Thanks!

 

They don't. It sounds like he's trying to make a quick buck from you. You would have alternator issues if your battery couldn't stay charged.

 

per cruiser54:

Thanks for your post.

We’re here to help, but you must understand that all Jeeps are not the same.
In order for us to give you more accurate advice and help, we must know the following, as applicable, along with detailed information as to the symptoms/problems etc:

Year
Model
Engine
Transmission
Transfer case

 

^^^ this. We'll wait

 

You sound like the people at Auto Zone. Lol

"I need windshield wipers?"

Auto Zone representative: "What motor has that got in it?"

Given the information he has provided, some quick Google-Fu reveals these codes aren't even remotely related to what his mechanic is telling him. They're related to engine misfires and evap system problems.

 

It's still good to know. That way the next thread the op starts, we can all help more effectively

 

so what

 

Honestly, I wasn't having any alternator problems at all, no dimming lights, etc. The only problem was a whistling sound. The "Check Gauges" indicator came on a couple of times. Battery is good, clean terminals regularly.
The ABS light was also on, but it was the wheel sensors.
When I asked how he knew the alternator was bad, he said he just inspected it.
I live in a small town & there are very few mechanics around, so I'm happy to have help, but this one has me stumped.
2001 Jeep Grand Cherokee
201K miles

 

No alternator problems at all, no dimming lights, etc. A whistling sound was the only issue. The "check gauges" indicator came on a couple of times. Battery is good. The ABS light was also on, but it was the wheel sensors.
When I asked how he knew the alternator was bad, he just said he inspected it. I live in a small town & there are very few mechanics, so I'm happy to have help, but this one has me stumped.
2001 Jeep Grand Cherokee
201K miles

 

without him doing an alternator output test there is no visual inspection test unless the thing is clearly damaged. I would ask for the results for proof of a bad alternator. I honestly think this guy is trying to get some extra unnecessary work out of you

 

+1
A vehicle has either a light or a gauge that should let you know there is a problem. Three weeks ago I noticed the needle on the voltage gauge on our '96 Blazer periodically drop then return to normal. We had just started out on a 1.5 hour trip. Went back home and pulled the alternator. Failed when tested at Advance Auto.