Battery light has been on for a little over a month, but truck has been running fine and was only showing low voltage on start up but once warm would run just under 14 volts. Read volts coming from alternator once truck was up to temp and they were 13.7 I figured it was the alternator starting to go. Well four days ago the truck wouldnt start "dead batteries" so I got her home and ordered an alternator. Yesterday I fully charged the batteries "two red tops" and today I put the new alternator in, a 160 amp AC Delco. Went to start the truck which was slow to turn over but it started and it threw a p0622 and the volts on the gauge were on the line between 9 and 14. Any ideas what is causing this?
P0622 Generator Field F Ctrl Circ Error
- Thread starter BLACKMAX1
- Start date
I was told once a red top dies it will soon take out the other battery. All sorts of crazy stuff happens when batteries start to go bad.
Optima used to make great batteries. I'm not sure where they went wrong. I've heard everything from patent issues to moving manufacture to out of country. I had a set of original Optima red tops that lasted two months shy of 17 years. My next set (purchased in 2010) made it a year and a half (and were already replaced once under warranty) before I sold the vehicle.
Getting back on topic... You may want to see if your ECU is sending the field signal to your new alternator. Not having dug into the LMM's diagnostic process for that code I'm guessing that the set conditions are to set the code when voltage output is low and the alternator is fully fielded. The fact that you had the battery light on with the old alternator may indicate bad batteries, or it may indicate a wiring issue to your alternator.
Did you have your old alternator tested? Have you checked the voltage output of your new alternator? I would start by testing your field signal at the alternator and go from there.
Getting back on topic... You may want to see if your ECU is sending the field signal to your new alternator. Not having dug into the LMM's diagnostic process for that code I'm guessing that the set conditions are to set the code when voltage output is low and the alternator is fully fielded. The fact that you had the battery light on with the old alternator may indicate bad batteries, or it may indicate a wiring issue to your alternator.
Did you have your old alternator tested? Have you checked the voltage output of your new alternator? I would start by testing your field signal at the alternator and go from there.
Yea thanks, I'm gonna check the new alternator now and then bring the old one and batteries to get tested.
Alright pass side battery is at 0, driver side 12.2 truck won't start. The alternator I took off was a Bosch 125 with a top pow and rear two prong connector that was never hooked up. The one I put on is a AC delco dr44g with a rear post and a top 4 prong connector. Is this alternator compatable with this model truck?
Well, old alternator tested good and I put it back in. The AC delco dr44g is not compatable and both batteries also tested good. Now as for the two prong plug on the back of the alternator does it go to anything? Chris at danville said it does but I cannot locate a plug that connects to it.
Can you take a picture of it for me leading into the harness? Number is 863-221-4213. Thanks
Haha, nailed it. I'm lookin through the harness now and can't find a plug that goes to it.
How was one battery at 0v and tested good? If both arent at 12.2-4 then you may have some bad cells. Load test the batteries and itll show if there any good. Batteries can show a surface charge with good voltage even if there bad.
I drove the truck with the dr44 alternator installed which wasn't generating power so I was just running down the batteries. I then took my batteries and old alternator to pepboys and the batteries were charged and tested and I was told they were good and same for my alternator. I'm still trying to locate the plug that goes into the alternator with no luck, I also do not have the setup to run a second alternator. If anybody has a picture of the plug leading out of the harness please post, it is the two prong plug.
I don't have access to factory wiring schematics here at work, but a cursory search indicates that your connector should look like this. Your alternator needs the connector in order to generate current - it is how the computer tells your alternator when to generate power. If it's not connected (which it apparently isn't) you aren't going to have power output.
The code you're throwing - P0622 Generator Field Control Circuit Malfunction is telling you exactly what's wrong. It is stating that your field control circuit (the connector) isn't connected. I hope you find wherever this wire is hanging out.
The code you're throwing - P0622 Generator Field Control Circuit Malfunction is telling you exactly what's wrong. It is stating that your field control circuit (the connector) isn't connected. I hope you find wherever this wire is hanging out.
I don't have access to factory wiring schematics here at work, but a cursory search indicates that your connector should look like this. Your alternator needs the connector in order to generate current - it is how the computer tells your alternator when to generate power. If it's not connected (which it apparently isn't) you aren't going to have power output.
The code you're throwing - P0622 Generator Field Control Circuit Malfunction is telling you exactly what's wrong. It is stating that your field control circuit (the connector) isn't connected. I hope you find wherever this wire is hanging out.
Yea thanks man, I got it running correctly last night. When I was goin through my factory harness after removing my egr and grid heater I unplugged the small jumper that connects to the main harness and goes to the alternator. I found a video on YouTube that showed me the connector and bam I knew exactly what happened. Thanks guys.