Hi folks, great forum!
I have a 2004 Chevy Silverado 1500 Z71 with 180,000 miles. It has a no crank, no start condition. I have replaced the ignition switch thinking that was the issue, but it still has the same problem.
I have had intermittent minor electrical issues for some time now. Sometimes the blower would stop working. Other times the radio would stay on after the key was removed and I opened the driver side door.
I have recently replaced the alternator, battery, knock sensors and spark plugs. Most of the new issues that recently popped up happened after I replaced the knock sensors under the intake. I had to pull up quite a bit of hardware to get to the sensors. I also did a lot cleaning and I probably got cleaner or water somewhere it shouldn't go like the PCM.
Anyway, since the knock sensor replacement, I started having a hard starting condition where the engine would start but wouldn't come up to idle unless I pumped the accelerator to about 2000 rpm. Then it would run great. Next day, same thing. It threw various ambiguous codes but nothing consistent. Then I narrowed it down to the alternator and had it tested. Sure enough, it was bad. But the battery had also been damaged. So I replaced them both.
It ran fine for weeks then one day, no crank, no start. After weeks of research, reviewing wiring diagrams and testing it seemed that the igniton switch was acting intermittently, so I replaced it. Two weeks go by without any problems then bloop! One morning, no start, no crank.
I've been able to isolate the problem to the crank relay circuit. I can jump out the crank relay and the engine cranks and even starts when the key is in the run position.
I do not have power to the small yellow wire at the top of the key cylinder housing circuit while the key is in start or run, whereas I did before. I also do not have power at the crank fuse either.
I have checked many fuse and changed a few around with no success.

Oh, another weird thing that is happening is the blower doesn't come on when the key is in the run or accessory position.

Two components I still need to look at are the Neutral Safety switch and the PCM.

Does anyone know a way to bypass the NSS or isolate the circuit in order to take the switch out of the circuit and therefore isolate the component?

Are there easier ways to check the PCM wiring without tearing everything apart?

I am stuck at this point and could use some real good advice, thanks!

 

UPDATE: Still having the same problem. I have checked all fuses, relays, grounds, etc.. I have also checked the PNP switch. I have 12v volts power to terminal 11. You're supposed to be able to jumper across terminals 1 and 11 then try and start the truck. But it did not start for me.

So I'm back to square one. The only way I can get it running is to pull the starter relay in the underhood fuse block and jump across terminals 30 to 87. Works everytime. But then it starts throwing powertrain codes and won't shift out of 2nd. It's a low drive mode meant for when there are transmission issues.

But, the main problem that has to be resolved first is the "no crank" condition.

Any advice would be appreciated.

 

Hello I'm having the same issue did you ever find out what was causing this?

 

I would also like to know if you have this issue resolved because I am having the same issue

 

Same issues I have changed the Infiniti on switch and housing and it’s still having t

 

I was having this issue and did some checking into the wiring diagram for the starter. Similar to others posting about this issue, I thought this was a simple starter or solenoid issue, so I took it off and bench tested it. It worked just fine. I reinstalled it and ran 12v to the solenoid input (to simulate an "order to crank") and it the re-installed starter engaged and ran, telling me it must not have been getting the voltage required to engage the solenoid. I checked the "crank relay" on the fuse panel and it had power on the "load side" (pin 30- always hot) and with the relay removed I could get the starter to run by jumping across to the appropriate pin (look at the diagram right on the relay to see which pin that is).
The pins on the "control side" of the relay did not produce any voltage to the starter, confirming that the "command to start" was not making it to the starter in the first place.
According to the wiring diagram there are only a few possibilities left: 1. the ignition switch (I don't suspect this at this time because all other functions appear in order with a key turn and this is a very very low milage 2016 (an RV with only 12k miles) 2. the neutral safety switch. I jiggled and moved it to neutral from park without help, and again this is not as likely as the final one: 3. the PCM (Powertrain Control Module).
Ah hah. The "crank command" comes from the PCM. To be sure the fuses have to be checked, the key has to be turned, the vehicle must be in park or neutral, the starter and solenoid must be good, but if you've checked those as I did then know that the PCM completes the crank circuit at the relay, allowing current to flow through the control side of the relay so the relay will close so the "load side" would activate the starter. I already tested that and knew that if closed the starter would spin. (Note that before that I also swapped relays first, and then checked that no voltage was getting to the control side of the relay with a key turn.
My next move is to replace the PCM which I hate to do, but the RV is immobile and towing a 28' RV and finding a shop that can fit it in the bay is a pain.
I'll post later about my luck, but one take-away from reading this is that lots of things impact the "order to crank" besides just turning the key and having a good starter. The PCM is the boss and is pretty much a "black box" and I don't know what is going on in there that keeps it from closing the crank circuit.

 

Got the same issue here, I researched online for a long time and still can't find the answer, and I didn't take my car to a repair shop, I'm afraid it will cost a lot

 

Hi
How could I identify the correct part (PCM) for a manual or auto shifter ? Does it even matter if the car is automatic or manual, regarding the PCM ?
Thanks for any input