Got a P0340 CEL code what to do
3rd Gear Member
Joined: Jan 2007
Posts: 721
From: Virginia
I've been having the same issue with the P0340 code coming up. Does it every so often. Not sure how to check which it is between alt. and cam sensor. My warrenty is up but I don't want to buy a alt. then find I need a cam sensor
Joined: May 2009
Posts: 1
From: GA
My 2005 Mustang GT started to display the P0340 code 2 weeks ago. I cleared the code twice and it came right back. After researching the error code over the internet, I decide that I will change my Alternator in the next couple of weeks. Well over the Memorial Weekend, I notice my dashboard lights getting dim by the minute, then my radio and all the lights shut off. The car stayed on I was lucky I still had battery power. I was not too far from my girlfriends house and drove it there. It sat stayed in her driveway 2 days. I had to wait until tuesday to get a new Alternator. My Mustang GT is out of warranty and I purchase my alternator from Auto zone. It cost me $214 plus $50 for the core exchange. The alternator is 135 amp verse the Ford stock Alternator is only 130 amps. The only problem it was special order from Autozone. So a long story short..... you have about 2 - 3 weeks from when you get the P0340 code to when your alternator fails.
Joined: Feb 2009
Posts: 8
From: FL
Repeat of the previous post. I bought an alternator from Autozone for $214. The alternator is pretty easy to get off the car. It took me about 15 mins. I took it to Autozone, it tested 'dead', and I ordered a new one. Took a day to get the new one, and I was back on the road.
I was getting 'jerky' power when accelerating slowly for about a week before the alternator quit. One night while driving around, I got the check engine light then about a half-hour later, as I was pulling into the house, the driving lights turned off, the ABS light came on, then the traction controll turned off. It seemed like, as the ECU was losing amprage, it was shuting down various systems. I turned the car off, then tried to re-start it with no avail.
I was getting 'jerky' power when accelerating slowly for about a week before the alternator quit. One night while driving around, I got the check engine light then about a half-hour later, as I was pulling into the house, the driving lights turned off, the ABS light came on, then the traction controll turned off. It seemed like, as the ECU was losing amprage, it was shuting down various systems. I turned the car off, then tried to re-start it with no avail.
3rd Gear Member
Joined: Sep 2006
Posts: 784
From: California
My car did this aexact same thing, I cleaned the throttle body out (wasn;t even that dirty) and it fixed my problem... the first time I got the code p0340 was over a month ago... my alternator is still running strong... Check the throttle body first... thats a free fix... then go with alternator. I'm waiting for mine to die now that I jinxed myself...
5th Gear Member
Joined: Mar 2007
Posts: 3,925
From: Deep in the <3 of Tx
It's the alternator if your voltage starts to dip in the low 13's and/or 12's. I had this code, would get some hesitation/bucking (mis-fire) and I could watch my voltage (with my radar detector and Aeroforce gauges) go all over the place. Replaced the alternator and all is good. I'd also watch the misfire reading in my aeroforce gauges count up most of the time when it would buck.
4th Gear Member
Joined: Feb 2005
Posts: 1,660
From: houston, tx
i was getting those codes also. i ended up changing out my cam position sensors with new ones purchased at autozone. still got the codes. turned out being an issue with my brenspeed tune. it was running too rich and throwing codes for the camshaft position sensors as well as the O2 sensors.
