P0340 Code and Resolution
#1
12-06-2021, 10:22 AM
P0340 Code and Resolution
I posted this elsewhere, but posting here too in the event it may actually help somebody with this issue. Thanks.
I apologize in advance, this may be a long post, But hopefully this may help someone if they care to read about my Hummer odyssey.
A little back story: Back in August I was offered a H3 2006 for a deal I couldn't refuse. I knew the original owner who bought it new and the person who inherited it as a result of the owners passing, So I knew going in, it hadn't been abused and just needed lots of TLC as the guy I bought it from isn't too mechanical and probably only did the bare minimum, one of which was changing the plugs and coils and also keeping up on oil changes. Anyhow He had been having a Hard Starting issue that seemed intermittent and as a result of his busy life, it sat for 8 months not really being run at all, the day I picked it up, He had it running, I drove it 200 miles home with no problems, next day I tried to start it and nothing, he did put a New battery in it days before me picking it up, So I knew that wasn't the problem.
I put my code reader on it and got a P0606 and from all my research it basically said replace the PCM no ends, if's or buts. I did that and got it running, But, immediately got a 'Crankshaft Relearn code' needed after installing the NEW PCM, So that resulted in me upgrading my Code reader to one capable of doing a Relearn, But hey, at least it was starting and running after the PCM and Relearn but then I got the P0340 code immediately for Camshaft Sensor Bank 1 --at this point, I'm like WTF? I'm by no means a mechanic but know enough to usually fix the basic problems, something like engine teardowns are beyond my skillset.
So anyway, I figured WTH I'll replace both sensors since these are original to the truck, I found the cheapest set I could thinking if it fixed the problem, I'd splurge for the expensive AC Delco's, I didn't want to just start throwing expensive parts in it. I installed the sensors and the H3 was actually a little bit worse, hard starting, making weird noises while trying to start and constantly throwing a P0340 code. But it didn't click yet. Bouncing ideas off my brother, researching anything I could find and watching YouTube I was pulling hair out, thinking maybe a Starter? (You know, the whole hard starting bit) after seeing what it took to replace, I was hoping that wasn't it, others suggested a alternator....So I'm thinking well it's probably all original, but it's going to have to wait for spring since I don't have a garage it can fit in nor is it heated and winter has arrived. Pricing out NEW Alt, Starter, Serpentine belt and maybe a New Camshaft actuator, I'm up over $350 in parts.
YouTube to the rescue, a video popped up in my feed where a mechanic was demonstrating how a bad alternator can be the cause of a P0340 code even though it's not one of the recommended actions. before he got to the alternator he tested the "Brand New" Sensors that were installed and found the intake one bad, The Light bulb went off after he mentioned the amount of "Brand New' parts his shop deals with that end up being bad, apparently He's noticed it much more recently. I actually paused the video, went out to the garage and found my Old sensors, I figured I had nothing to lose, So I cleaned them with Brake Cleaner and Steel Wool, they both had caked on gunk that looked like rust, but I'm assuming was dried motor oil and 15 years of build-up. Anyhow, installed the intake side, Truck fired up immediately and has been running fine ever since. So I plan to get NEW AC Delco sensors in the near future, but will probably run it until it causes another issue just to see how long it lasts.
We always hear everyone cleaning their MAF sensor, Throttle body etc....It never dawned on me to try cleaning the old sensors but I was desperate. So anyway, after owning a H3 hummer for 4 months, I can finally drive it with confidence that it's actually going to start back up. As an Added Bonus if you read this far, When I had the problem and was trying to start the truck, I noticed if I let go the key back to the 'ON' position, the starter would continue to crank the engine. This also made me feel it was a starter issue, I googled it and while it can be a Starter issue, the simple fix was to spray some dry graphite into the lock cylinder, those simple fixes never seem to work for me, But that actually did. Food for thought if anyone is having key/lock issues.
Thanks for reading
TJB
I apologize in advance, this may be a long post, But hopefully this may help someone if they care to read about my Hummer odyssey.
A little back story: Back in August I was offered a H3 2006 for a deal I couldn't refuse. I knew the original owner who bought it new and the person who inherited it as a result of the owners passing, So I knew going in, it hadn't been abused and just needed lots of TLC as the guy I bought it from isn't too mechanical and probably only did the bare minimum, one of which was changing the plugs and coils and also keeping up on oil changes. Anyhow He had been having a Hard Starting issue that seemed intermittent and as a result of his busy life, it sat for 8 months not really being run at all, the day I picked it up, He had it running, I drove it 200 miles home with no problems, next day I tried to start it and nothing, he did put a New battery in it days before me picking it up, So I knew that wasn't the problem.
I put my code reader on it and got a P0606 and from all my research it basically said replace the PCM no ends, if's or buts. I did that and got it running, But, immediately got a 'Crankshaft Relearn code' needed after installing the NEW PCM, So that resulted in me upgrading my Code reader to one capable of doing a Relearn, But hey, at least it was starting and running after the PCM and Relearn but then I got the P0340 code immediately for Camshaft Sensor Bank 1 --at this point, I'm like WTF? I'm by no means a mechanic but know enough to usually fix the basic problems, something like engine teardowns are beyond my skillset.
So anyway, I figured WTH I'll replace both sensors since these are original to the truck, I found the cheapest set I could thinking if it fixed the problem, I'd splurge for the expensive AC Delco's, I didn't want to just start throwing expensive parts in it. I installed the sensors and the H3 was actually a little bit worse, hard starting, making weird noises while trying to start and constantly throwing a P0340 code. But it didn't click yet. Bouncing ideas off my brother, researching anything I could find and watching YouTube I was pulling hair out, thinking maybe a Starter? (You know, the whole hard starting bit) after seeing what it took to replace, I was hoping that wasn't it, others suggested a alternator....So I'm thinking well it's probably all original, but it's going to have to wait for spring since I don't have a garage it can fit in nor is it heated and winter has arrived. Pricing out NEW Alt, Starter, Serpentine belt and maybe a New Camshaft actuator, I'm up over $350 in parts.
YouTube to the rescue, a video popped up in my feed where a mechanic was demonstrating how a bad alternator can be the cause of a P0340 code even though it's not one of the recommended actions. before he got to the alternator he tested the "Brand New" Sensors that were installed and found the intake one bad, The Light bulb went off after he mentioned the amount of "Brand New' parts his shop deals with that end up being bad, apparently He's noticed it much more recently. I actually paused the video, went out to the garage and found my Old sensors, I figured I had nothing to lose, So I cleaned them with Brake Cleaner and Steel Wool, they both had caked on gunk that looked like rust, but I'm assuming was dried motor oil and 15 years of build-up. Anyhow, installed the intake side, Truck fired up immediately and has been running fine ever since. So I plan to get NEW AC Delco sensors in the near future, but will probably run it until it causes another issue just to see how long it lasts.
We always hear everyone cleaning their MAF sensor, Throttle body etc....It never dawned on me to try cleaning the old sensors but I was desperate. So anyway, after owning a H3 hummer for 4 months, I can finally drive it with confidence that it's actually going to start back up. As an Added Bonus if you read this far, When I had the problem and was trying to start the truck, I noticed if I let go the key back to the 'ON' position, the starter would continue to crank the engine. This also made me feel it was a starter issue, I googled it and while it can be a Starter issue, the simple fix was to spray some dry graphite into the lock cylinder, those simple fixes never seem to work for me, But that actually did. Food for thought if anyone is having key/lock issues.
Thanks for reading
TJB
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