2006 LS2 cam position P0340

[NChevelle71]

We put a 2006 LS2 with 45,000 miles on it in a 68 Caddy about 8 years ago. The guy we did it for just got it back finally from getting painted. When we tried to start it it didn't want to start. So we cleaned the fuel system put new injectors and plugs in it and it started so we could move it. So now I got the gages in it and we can see it has a engine code P0340 cam position circuit malfunction. And it starts hard every few times back firing thru the exhaust. we changed the cam sensor and the code has not gone away and either has the problem. we checked continuity of the wires back to the computer and they seemed fine. The wire harness is from Street and Performance who is no longer around to ask questions. Has any one else experienced similar problems and came up with a solution? Or what and how can I check this system. I am out of town for the week I can post tune files when I get back home.

[blindsquirrel]

P0340 - Document ID_ 1665058.pdf

screenshot.25-03-2025 07.12.24.png

[NChevelle71]

So I'm back from vacation. I tried to read the computer for this LS2 and I get some errors. (this keeps getting better) I took some pictures of the errors but I can't seem to download them on to here. But it is a E40 ECM, GM Gen 4 V8/ 2006 Pontiac GTO 6.0 L
I get this error: Controller unlocker: x35 invalid key / controller unlocker: x36 exceed number of attempts
Does this mean the ECM is locked?
Can I unlock it with HPT?

[ratsnotmice]

If the computer is also from Street and Performance, it will most likely be locked.

[NChevelle71]

I have a different computer on the way so we can start fresh.

[relicdew]

Verify the cam is pinned properly as blindsquirrel stated. GTO vehicles were Australian based platforms and didn't use the CAM extension from GM. Position's A and C may need to be switched if it was wired for the wrong connector.
Is your wiring harness plugging directly into the cam or do you have the common GM cam extension that plugs into the cam and provides a more convenient plug in location to the oil pan? Do you have a photo of your cam connector?

Street and Performance used some guy named Tony to do their files and he always seemed to lock them for whatever reason.

[NChevelle71]

The wire harness is plugged directly into the sensor there is no harness on the front of the engine like I have seen on other LS engines. I don't have a pic of the cam connector. We had a good relationship with Tony years ago but lost contact with him once Street and Performance closed down.

[Alvin]

I've been saying I think it would be smart to try one of those jumper harnesses. It should have had one

[blindsquirrel]

If CMP 'A' goes to C2 44, and CMP 'B' goes to C2 15, and CMP 'C' to C2 26, it doesn't matter what position the wires are in when (or if) they pass through an inline jumper/connector.

[NChevelle71]

We checked continuity of the wires from the sensor to the computer and they all checked ok. I will double check tonight that they are in the correct locations.

[NChevelle71]

The wiring is a little confusing. The plug that goes into the sensor is labeled A - B - C (that plug is on my Street and Performance harness so that could be wrong) and in the schematics the plug is labeled A - C - B. My ground wire on my plug is in the middle of the plug. From the schematics it looks like it should be on the end of the plug in position B? Or am I looking at this wrong.

[blindsquirrel]

I believe I have this sorted - GTO has no extension/jumper, so the pinout shows the positions at the sensor. The others that have the extension/jumper, the pinout shows that connector between the main harness and the extension and the pinouts at the sensor itself are not described anywhere in the manuals.

GTO pinout (at sensor).png GTO component view.png

Trailblazer pinout (at subharness).png Trailblazer component view.png

If the pins are marked on the sensor itself, use those (match to the wiring diagram). Sometimes the labels are down inside the connector beside the pins.

[NChevelle71]

Thanks blindsquirrel I appreciate all your help. I'll have to pull that sensor and see if I can see any letters on it. I don't remember seeing any but I'll have to look closer.

[relicdew]

The sensor won't have letters but the CONNECTOR will. You may have to remove the white 3-way TPA lock. NChevelle71 when you see the schematic, it doesn't have the letters in "order" but that doesn't matter. A is A, B is B, and C is C regardless of what arrangement they show on a schematic. Post a picture of your CONNECTOR please. It's not uncommon for folks to FORCE or manipulate a connector that is A B C into a plug it's not supposed to be in by modifying the key-way. However, the goofballs at GM have A and C in different positions depending upon which CAM connector you have and it matters if you're plugging directly into the cam itself OR the OEM Jumper harness that you likely do NOT have since it's a GTO engine unless you were told by Street and Performance to do so to fit their harness.

Since you stated you're plugging directly into the CAM itself, which is normal for AUS based engines, I would like to see a picture and I can assist you on the pinout!

[NChevelle71]

relicdew I have had the white lock off of the connector to see the A B C markings. I will take some pics tonight.

[NChevelle71]

I checked the wires from the connector to the computer last night and
"A" red wire goes to 44
"B" black wire goes to 15
"C" brown wire goes to 26

I attached some pics (hopefully). On the inside of the sensor you can see "+" / "-" / "O" marked

[blindsquirrel]

Does "A" = "+", "B" = "-", "C" = "O"? (the markings should correspond to +ref, gnd ref, & output)

This may sound crazy, but has anybody looked through the little hole in the timing cover yet to see if it has the right cam sprocket on it?

[NChevelle71]

Yes the "A" = + , "B" = - , "C" = O. I ran out of time last night so I didn't look into the hole. I did try to feel if the sprocket was loose but it seemed fine. The new computer should be here in the next few days so we can give that a try. Does anyone have some info of what I should do to the computer for a good start up tune? I know I need to turn the Vatts off but what else should be done to start? Thank you guys for all your input.

[Alvin]

have you tried a new sensor? The china on that worries me.. lots of bad brand new parts lately.

And yes check the cam reluctor if you can. It should be a big half moon.. nothing else. This got our shop this week. ZL1 that caught on fire after customer installed his own brand new motor in his own garage. It was towed to us and we repaired the harness because they are impossible to find, won't start for us.. our first thought is our harness repair went wrong somewhere... But I know GEN 4's sometimes will not start with a bad cam signal. pulled the cam sensor out and saw the wrong reluctor wheel behind it.

I feel so lucking finding that.. that had the potential to waste a lot of shop time.

[Alvin]

This is what you should have.. and what my ZL1 customer this week shouldn't have had. lol

IMG_2111_1.jpg