LLY: Help Lly p0016
- Thread starter brokesmoker
- Start date
Im not buying one because such scanner with dual channel scope function is the price of my whole truck. We're not talking about a 2gran autel scanner.
And the scope function Id only use for this, so I'll buy a new engine or trans before that top end scanner.
I cannot find a place that has one, let alone a place that'll let me borrow a 15grand scanner.
So I'm calling for the professionnal mecanics in Montreal that may have one since they actually make money out of it.
And the scope function Id only use for this, so I'll buy a new engine or trans before that top end scanner.
I cannot find a place that has one, let alone a place that'll let me borrow a 15grand scanner.
So I'm calling for the professionnal mecanics in Montreal that may have one since they actually make money out of it.
I'm pretty sure they mean get something like this: https://www.amazon.com/dp/B012938E76
You don't need some insane multi-GHz scope, at idle the signals will be about 650 Hz. The scope I linked is over 10,000 times faster than you need for less than $400.
You'll want to make sure you get appropriate probes since I don't know what all that one comes with. It was just the first one I saw on Google.
While a normal scope like this CAN work, it's also playing russian roulette with it's front end without (possibly)specialized probes i'm unlikely to find.
Im sure a tech wouldnt charge me 400+ for a simple scan with a automobile scope such as a picoscope. Problem is, dealer refuses. They want a blank check to fix the whole issue.
Still looking, never had a code on a car for so long before, driving me nuts.
Im sure a tech wouldnt charge me 400+ for a simple scan with a automobile scope such as a picoscope. Problem is, dealer refuses. They want a blank check to fix the whole issue.
Still looking, never had a code on a car for so long before, driving me nuts.
That scope is rated 300Vrms on its analog inputs, which is more than enough for a 12V square wave. And you can find cheaper scopes if you look, this was just an example.
For what it's worth, I wouldn't build the harness adapter and scope the CMP and CKP for much less than $400, as that's only 4 hours of labor. But it certainly can be done cheaper if you find the right shop, especially if they already have the harness adapters made.
Hope you find a shop that'll diagnose it for you cheaply. I have no other ideas besides the previously suggested plan to scope the signals and see how they compare to the theoretical correct waveform.
300v isn't that high, expecially dealing with possible transient of injector coils running on 48V already. You need some MOV and such in there just to clamp that. As for the harness adapter, I have no problems with puncture probes, just a dap of liquid tape afterward. So I'm pretty sure it can be checked on the cheap.
It's simply finding a good bloke that's willing to accept a few bills in exchange of simply doing what I ask, without securing a mecanical job afterward.
BUT, I could disconnect the whole truck, and only connect the sensors to a normal scope come to think of it. Maybe that's what you were suggesting all along. I can do the test on starter speed. It would still show me correlation or not, but wont show me anything about the ecm but by then I'd already know. I already ruled out the wiring loom.
It's simply finding a good bloke that's willing to accept a few bills in exchange of simply doing what I ask, without securing a mecanical job afterward.
BUT, I could disconnect the whole truck, and only connect the sensors to a normal scope come to think of it. Maybe that's what you were suggesting all along. I can do the test on starter speed. It would still show me correlation or not, but wont show me anything about the ecm but by then I'd already know. I already ruled out the wiring loom.
Yep, that's one way to do it. And we were talking about probing the CMP & CKP, not injector drive voltages.
CMP = cam position sensor
CKP = crank position sensor
Neither of those should go over 12-14V during operation.
If you did want to probe the injector drivers, that scope is rated 300Vrms & 1000Vpeak, which is plenty safe for the flyback on the injector solenoids. There should be clamp diodes or similar in the FICM, so all you'd have to worry about is line losses preventing the snubbing if you probe close to the injector instead of close to the FICM. I'd feel comfortable using this scope for that. But it wouldn't really tell you anything about your current code, as you say it runs fine (aka injectors being fired normally), just has the correlation code.
On the LS engines, if you've had the crank or cam out, there is a relearn to let the ECU know the new angle variation is expected. This is called a C.A.S.E. (Crank Angle Sensor Error) relearn. I don't know if you can do a CASE relearn on a Duramax, but it might be worth looking into. I've had a few LB7s apart and none of them had any miscorrelation, so I have never even looked if it is possible. As has been suggested before, I'd be suspicious of a slight bend in the dowel pin(s) causing the alignment error the ECU is complaining about.
And you could always try and find a buddy's ECU to swap temporarily to conclusively determine if the issue is in the ECU or not.
There is no relearn for the Duramax, but getting back to the scope, I use a fluke 123 scopemeter, has dual channels, is overkill for automotive use, and bought it used for $600. A simpler one like Dave linked would work fine, you can find good ones on Amazon for under $300. For price referencing, you've already spent that amount chasing this problem.
Yeah, There's no relearn on my duramax. A gm tech I went to told me that. At least none on this 2005 year.
Here's more info to this. From the Gm Manuals
Condition for setting the DTC
When the engine is cranking or running, the cam sensor pulses received by the ecm does not equal 3 in one crankshaft revolution.
It doesnt see enough pulses. It sees "some" otherwise p0340.
You know the tab on the cam reluctor? Im starting to think it could have something to do with not the sensor, but the depth of it and the distance to that reluctor.
I'll keep you posted
Here's more info to this. From the Gm Manuals
Condition for setting the DTC
When the engine is cranking or running, the cam sensor pulses received by the ecm does not equal 3 in one crankshaft revolution.
It doesnt see enough pulses. It sees "some" otherwise p0340.
You know the tab on the cam reluctor? Im starting to think it could have something to do with not the sensor, but the depth of it and the distance to that reluctor.
I'll keep you posted
I really have a hard time understanding why you refuse to invest in a scope and a few minutes online learning how to use it. It would've already paid for itself.
There's is 2 ways to tackle this. Using good infos and proper tools, or reverse engineering
Now, if im to buy a scope, which I know how to use, and don't know what the actual signals are supposed to look like, it's not gonna do anything but burn a 500$ hole in my pocket. If I have a scope, and a known good graph then that's a simple job.
That why Id rather pay a guy that has the scope and known good graph. Fast, easy.
Or reverse guess what should be good. Now I know it expects 3 pulse from cam for one crank rotation. I could compare all the pulses to see if one has lower amplitude. But I still wouldnt know the correct timing relative to crank sensor. That's where Im afraid I would lose out, rather that doing what I am. Piece by piece getting infos until I know exactly what it needs to be. Remember, I need to be 100% sure of the signals otherwise I can't rule out a bad ECM. Wiring is proven good.
At 265 00miles, It could be cam reluctor (new sensor), sheared crank pin on crank or bad ECU.
Now, if im to buy a scope, which I know how to use, and don't know what the actual signals are supposed to look like, it's not gonna do anything but burn a 500$ hole in my pocket. If I have a scope, and a known good graph then that's a simple job.
That why Id rather pay a guy that has the scope and known good graph. Fast, easy.
Or reverse guess what should be good. Now I know it expects 3 pulse from cam for one crank rotation. I could compare all the pulses to see if one has lower amplitude. But I still wouldnt know the correct timing relative to crank sensor. That's where Im afraid I would lose out, rather that doing what I am. Piece by piece getting infos until I know exactly what it needs to be. Remember, I need to be 100% sure of the signals otherwise I can't rule out a bad ECM. Wiring is proven good.
At 265 00miles, It could be cam reluctor (new sensor), sheared crank pin on crank or bad ECU.
My truck has the exact same code/issue. Its a built motor, keyed crank (so no pin to fail), 2x new GM cam/crank sensors and yet no fix.
I'm guessing a tooth on the reluctor wheel is slightly out of alignment. Simple solution is turn the code off if the truck runs just fine.