Ls3 crank sensor p0315 code

[Zedn]

Not sure, I thought the cam sensor tells the ecu what the valves are doing.

I have done some more testing and found an abnormality. Can anyone do me a favour and test the voltage of their cam sensor wires?

I tested both cam sensor wires and crank sensor wires and found the signal wire for crank has 5v but the signal wire for the cam sensor has no voltage. Given they are the same type of sensor I thought they would be the same.

I check the crank signal wire by tapping a test light on it and the pump comes on and throttle body moves but it doesn't fire spark or injectors.

I'm wondering if it's the cam sensor wiring now.

[Modena]

Yes of course the cam sensor reveals cam position, but as the cam turns one time for every two crank revolutions, I would think the cam sensor is the signal being used to gauge and output crank RPM, because LS engines output one pulse for every 2 crank revolutions, in other words you set your tach to 4-cylinder mode.

Anyway this is not helpful to your issue I know! I would test mine for you but mine has never even been turned over yet so who knows, and it's not in a position for me to hook it up right now.

[Zedn]

I think your right. I disconnected the cam sensor and it no longer showed rpm. That was 2 seconds before the obd cable packed it in.

[RICK LAKE]

Zedn Can you give me the year or 8 digit number on the back of the ecu and the motor you are working on. I have full access to gm info. I am using a gto 2005. p0807doesn't show. there is only power wire in and out to ecm. There is a larger slot in the crankshaft to tell the sensor with #1 cylinder is either at TDC or 50 degrees before. You are going to get an high low voltage with the crankshaft sensor. Need this info for the correct diagnosis. The motor should also run with either camshaft sensor or crankshaft sensor disconnected and run in a backup mode. What is the fuel pressure?? Rick

[Zedn]

Fuel pressure is around 60psi. But injectors arnt opening.

Havnt got the service number handy so have to pull the ecu to find out. It's out of a VE commodore 2009. Same as Pontiac 2009 I believe. With a 2009 ls3.

3 wire crank sensor. Should be power, ground, signal. I have 5v on the crank signal wire from the computer. But no voltage on the cam signal wire. I would have thought they would read the same being the same type of sensor. I have posted on some other forums to find out if that's normal.

[RICK LAKE]

Zedn I am going with a 2009 G car and LS3 motor.
all the fuses are good and you have power and gounds on all ecu connectors. Battery voltage above 12.0 volts.
Lets start with cam shaft, 3 wires A is 5.0 volt power, spec is 4.8-5.2 volts anything outside this, bad wiring of ecu internal problem. We go with good readings. test. remove CMP sesnor from motor. Wires are hooked up. I hope you have a tech2 or top of the line scanner or this is going to be a problem Your scanner needs to show the count of the camshaft sensor. What we do is run a piece of steel across the sensor and you should get 1 count on the scanner. If not back probe "C" terminal with a good volt/amp meter, (digital) on low dc voltage and want to see a spike when you run the steel acroos the sesnor. Ign is on when testing. No signal bad sensor. Look inside hole where sensor comes out of aND CHECK FROM DAMAGE. should see slotted pin wheel. crank motor and make sure it move with breaker bar on crankshaft bolt and wheel is not loose. If this test passes going to crankshaft sensor
How easy is it to see and work on? Pull header if needed.
Crankshaft sensor. same as camshaft sensor for wiring. "a" is 5 volt from ecu, spec 4.8-5.2 volts anything else, test wires with load test and if pass replace ecu. wires OK same test wire"a" 5.0volts, wire"b" ground back to ecu. Make sure on both of these grounds to test with ecu connector unplugged for resistance. It's possible a wire rubbed through and is hitting a grounded part of the car frame and getting a faults ground. check both ways. OK wires are good we need a varying dc volt reading from sensor. If your scanner is good we should see a count number as you run a piecs of steel across the sensor.
You said you have an rpm reading so I think this sensor is ok. May sure the reluctor wheel is tight on the crank shaft. This covers the test for the ign system.
Couple of side ideas, Does your motor have a VLOM? Is it still operating or removed from the system?
OIl pressure switch is working and you have a reading of pressure. Should know that this switch doesn't give accurate pressure readings. There are 3 or 4 micro switch inside that are on or off and GUESS the pressure reading. YES Guess, you might want to add a direct line to a gauge. Some motors will shut down with no pressure, crank and stall. prevents more damage to motor.
I am starting to think either the ECU is screwed and in lockout where you can't get the car to run and will have to replace. Reason here, it controls both base spark output and injector fire. YOu have neither. Other check is igntion module. Go to junkyard and get a couple of spares that match the numbers on it, (8 digit) and try for a test. Motor runs, bad ignition module doesn't run back to ECU. Final note, YOU can't reprogram an ECU if it's locked out. YOU can't unlock it either. I talked to GM engineering on this on friday. You can add or remove info but once locked it's a 1 pound piece of junk
There is a way to batch fire all the injector or coils I will have to look this up if the tests above don't work. Good luck Zed. PS WHERE'S GAV??? I have better than 30+years with GM as a tech GAV> Paper work out the A$$ Where are you?? You should have this car running allready or at least giving the info I gave to check the 2 sensors. Very disappointed in you. Do you think this is more wrong info?? THis comes straight for the GMSI website. I shorten the tests and made simpler for Zed. Thanks for all your help. Rick

[Zedn]

Hi Rick,

Appreciate you typing all that out. I have done all of that except tapping the metal on the sensors. I don't have a decent scanner unfortunately. Looking at maybe buying hp tuners.

When you say ignition module, what do you mean. I don't recall there being one on these motors.

When I tested the wiring for the cam and crank sensors, I found the signal wire from the computer to the crank sensor has 5v. That's the signal wire, not the power wire. So I have 5v on the two outer wires of the plug. That I wasn't expecting because the cam signal wire from the computer has no voltage. Being the same type of sensor you would expect the signal wire from the ecu to be the same.

I checked for continuity between the signal wire and the 5v wire thinking maybe they have been pinched somewhere but there is no continuity between the two.

It appears the ecu is outputting 5v on the crank signal wire. I'm trying to find if this is normal. Do you know?

I don't think it's a sensor. I think it's either power feed, earth or ecu as there are no codes. I thought I found it today as I discovered an earth wire was a bit loose in the ring terminal. I soldered it up but it didn't fix it.

[RICK LAKE]

ZEDN Ign on, test for between ground wire and signal wire is 4.8-5.2 volts. If less check the wiring or run new wire and connectors. If you think the wiring is ok, Replace the ecu. That's all to this part of the test. Without a good scanner tool this is not an easy curcuit to fix. Need a fluke 88 ohm meter for mid/ max readings in milli seconds. You have your answer. Good luck with car. Rick L.

[joyridin']

If it is an LS3 in 430hp form, why can't you just get a GMPP computer and plug it in? The only issue would be factory gauges, but I would guess you are not running those anyhow.

Can this be done?

[Zedn]

GMPP would require the full harness and pedal as its a different ecu.

Thanks Rick. I have ordered VCM suite so should be able to do some more thorough testing before replacing anything. It's starting to look like ecu, but I want to make sure before buying one. There isn't anything to say it is the crank circuit, that has been assumed but from what I have read on the net, my symptoms are typical of many different problems.

[Zedn]

I finally found the problem tonight.

First of all Modena, you were incorrect about the cam sensor showing RPM. The problem was the cam sensor after all. Thinking this completely threw me off the scent. I will know not to listen to you in the future (j/k)

When I had disconnected the cam sensor the scanner stopped showing rpm, which was also seconds before the scanner died. The lack of RPM was the scanner dying, not the fact I had disconnected the cam sensor.

I hooked up my new HPtuners tonight and found no cam signal was showing from the sensor. I checked continuity between the senor and ecu and there was none. Started pulling the back off the cam sensor connector and the signal wire fell out. It wasn't crimped on the wire properly.

I should have found this. As I mentioned above I new there was inconsistency between the signal wires of the cam sensor and the crank sensor because the crank had 5v and the cam had 0. I was thinking the crank sensor wire was shorting to another 5v wire. Everyone I asked this question to said the crank should have 5v on signal but didn't say anything about the cam signal and cause I thought it was giving me RPM I ignored it.

Anyway I definitely have fuel and spark now cause it coughed and back fired when I tried it quickly. I cant start it because it is under my kids bedrooms and they are sleeping but tomorrow she will roar again!!

[Gav]

Well done, very satisfying finding problems like that. ��