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I am totally at fault here, I bought an 03 Envoy without doing as much due diligence as I should have. Lesson learned. The thing had some serious overheating problems and after a lot of part replacing I decided to replace the engine with one from a 04 trailblazer. Everything is swapped over and the car runs great, no stalling, no rough idle. In fact, I wouldn't know that there was anything wrong except that the check engine light is on. The only code it is throwing is P1345. I replaced the cam shaft and crankshaft position sensors, and the VVT solenoid and none of that helped. Thanks to this forum, I learned that may need to do a case relearn, so I tried that and it didn't work either. I didn't feel like to doing all the work to replace the cam phaser so I took it to a shop. They replaced it, checked the timing chain and said it was fine, but they are still getting the same code.

Their diagnostic said to check the knock sensor, fuel rail, and spark plugs. Wouldn't these throw their own separate codes? The knock sensor is the one that came with the donor motor, as is the fuel rail, and the spark plugs are brand new. When it came down to it, they are saying I need to replace the motor again.

Any advice is welcome! Am I missing something because the motor is from a different year and make? Are there certain parts that need to be from the 03 Envoy
 

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how was the case relearn done?

do you have a scanner that can read the actual cam angle, desired cam angle, cam angle variance and such things? I can read these with a smartphone app and a $12 bluetooth obd reader.
 

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how was the case relearn done?

do you have a scanner that can read the actual cam angle, desired cam angle, cam angle variance and such things? I can read these with a smartphone app and a $12 bluetooth obd reader.
I used a Vident Scanner, which was honestly the cheapest scanner I could find that would read and write. The process seemed match the process in the youtube videos of people using the Tech 2 to do the case relearn. The case relearn was done before sending it to get the cam phaser replaced. I forgot to ask the mechanic if they did a case relearn when they were trying to diagnose it. I am going by there tomorrow and plan to find out.
 

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So it runs good and the issue is the p1345? Is your gas mileage poor? When you replaced the cam phaser was the old one still functioning?
You can test the phaser by applying 12v and checking if it moves. I've had parts come that don't work out of the box. Check the new parts just to make sure that they work. Before buying anything else test the suspect parts then if they are bad test the new parts before installing. I ordered an alternator for a Land Rover HSE LSE cause I couldn't find one locally. When it came and I installed it I was still having the same problem. The last thing I did was take the new part to get it tested and the test came back with bad diodes. It was bad right out of the box and I never thought it might be the new part. I put a diode in it and it worked. I just got my 2004 TB EXT LS and the only part I've got that I didn't need was the ignition switch. Other than that all the other parts I've got I tested to be sure that the part is in fact defective. At first I didn't think that the fuel pump was bad cause I could hear it run and the first time I tried to start it the engine started but was sputtering really bad then it went off and never started again. I thought it was the throttle by wire system because of the figures I was getting on my scanner then I thought it was the ignition switch so I ran out and got one before I tested the old one and it wasn't the issue. The fuel pump had burst the feed line that comes from the pump in the assembly to the metal line on top of the tank. It had to have been connected at first but when it pressurized the rotten lines burst. When I finally tested the fuel pressure and got nothing even though the pump was running I realized that it was bad.
 

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So it runs good and the issue is the p1345? Is your gas mileage poor? When you replaced the cam phaser was the old one still functioning?
You can test the phaser by applying 12v and checking if it moves. I've had parts come that don't work out of the box. Check the new parts just to make sure that they work. Before buying anything else test the suspect parts then if they are bad test the new parts before installing. I ordered an alternator for a Land Rover HSE LSE cause I couldn't find one locally. When it came and I installed it I was still having the same problem. The last thing I did was take the new part to get it tested and the test came back with bad diodes. It was bad right out of the box and I never thought it might be the new part. I put a diode in it and it worked. I just got my 2004 TB EXT LS and the only part I've got that I didn't need was the ignition switch. Other than that all the other parts I've got I tested to be sure that the part is in fact defective. At first I didn't think that the fuel pump was bad cause I could hear it run and the first time I tried to start it the engine started but was sputtering really bad then it went off and never started again. I thought it was the throttle by wire system because of the figures I was getting on my scanner then I thought it was the ignition switch so I ran out and got one before I tested the old one and it wasn't the issue. The fuel pump had burst the feed line that comes from the pump in the assembly to the metal line on top of the tank. It had to have been connected at first but when it pressurized the rotten lines burst. When I finally tested the fuel pressure and got nothing even though the pump was running I realized that it was bad.
I had a shop replace the phaser and when it was still throwing the same code, P1345, I had them do a diagnostic. I would hope that during their diagnostic they would have had to make sure the phaser was working properly. I haven't really driven it a ton since the phaser replacement because it isn't registered because I can't get it smogged; so I don't know how the gas mileage is effected.
 
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