I was troubleshooting a misfire issue on cylinder 3 (it turns out to be the pigtail for that ignition coil) and doing maintenance on my buddy's H3, 3.7. It called for a crankshaft sensor to be replaced P0017 code (it was still present after changing the two camshalt sensors) Well we did the replacement of the crankshalf sensor, tried to do the relearn and it failed miserably (the misfire was still present at that time and it was running very rough). Since that failed attempt, I tried to do the following:
-Replaced the ignition switch (my friend ended up breaking the one as I was trying to clean it.
-Tested from spark, all 5 connections have spark
-Used a different battery
-Changed the ECU (we established that it was faulty because no code were showing while we were attempting to start several times without the crankshaft sensor present (I was testing to see if the new part was defective)
-Check for fuel of the check valve and added 10 liters of fuel to ensure it was not the fuel pump that was gone.

I'm not sure what else to check.

Any thoughts ?

 

Welcome.

YEAR and MILES???? We supposed to guess? It makes a difference since you are indiscriminately swapping parts and sensors.

This is what happens when you throw stuff at a problem without diagnosing the problem in hope that something sticks. You now have scrambled variables all over the place in different directions.

Changed the ECU (PCM)? With what from what, programmed how and by who? Go back to the beginning, put the old crank sensor back with the original PCM, then see what you have.

 

Its a 2007 Hummer H3 with a 3.7 mileage is about about 156919 miles (252538kms)
The hummer was not driving very often when my buddy bought it so we tackle all the codes that were showing up via our code reader (P0017, P0304, P0354, P0446) hence we did change parts
(The parts were a pigtail for the ignition coil for cynlinder 4, ignition coils, spark plugs, 2 camshafts sensors) P0017 remained so we went for the crankshaft sensor replacement

The new ECU got ordered from All Computer Resources and programmed by them.
I did the test the old ECU several time with the old crankshaft sensor and the new crankshaft sensor , still the same issue of cranking without starting at all (scanned multiple times and it would not generate a code)


Currently with the new ECU, I get P0315 for a relearn which obviously I cannot do because of the no start condition.

 

Likely not the crank sensor, but more likely passlock since you need to relearn your new ignition switch.

30 Minute Learn Procedure
1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON; the vehicle will not start.
3. Observe the SECURITY telltale; after approximately 10 minutes the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds.
5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes; the
vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK.
6. Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or password.

 

Sounds good, I will do that procedure.
I'm assuming that I will have to do it every time I'm introducing another key into the passkey system (the H3 cam with two keys )
I will report back after doing the procedure

Thanks

 

The keys are not chipped, the new switch is all that need to learn.

 

Sounds good

I finished the procedure and the H3 is not starting
At first, I see the security telltale before attempting to start. I try to start, it doesn't start but the telltale disappears
I do it a total of 3 times and yup still no start.

The system is allow me to continue to crank, which it was not going when I originally change the new switch.
I still have the p0315 but now I also have a reduced power showing on the dash... Not sure if that's related.

 

Inspect/clean ignition switch/connector contacts.

 

Reset procedure:

 

Ill try the procedure again. The connections looks ok when I did the replacement of the ignition switch but I will double check tomorrow and keep you guys in the loops

Thanks