i have a 2008 g35 sedan sport manual. no crank no start just a click. i know i know... changed battery, changed starter... twice, tested continuity voltage etc of b and s circuits (hot and signal to starter) they're all good. when testing continuity etc at ipdm i found that one of the wires associated with the starter relay control is not changing state whether the clutch is pressed in or not, it always shows battery voltage (the green wire on pin 30). I have gotten the motor to turn over by manually applying voltage to the s circuit at the starter. I have also replaced the ipdm and basically tested everything possible if anyone has any suggestions please help lmao.

 

Follow the troubleshooting steps in the FSM, section STR - Starting System.

Ring out the clutch safety switch to make sure it open/closes properly, the BCM controls the external module relay on the IPDM, there is also the internal relay controlled by the IPDM via CANBUS.

IPDM wire 30 is the clutch safety wire, voltage should switch on/off as you depress the clutch. Keep in mind there are TWO switches mounted on the clutch pedal, one is the start switch, one is the cruise disable switch.

Bench test the external starting relay.

Check voltage states where the relay plugs into the IPDM to make sure the BCM is sending the crank signal.

It's a really simple system, read the FSM, troubleshoot, win. Randomly throwing parts at the car hoping something will work is the wrong way to fix cars, very expensive and time consuming replacing parts that were working just fine.

 

I have gone through the whole diag process in the STR section twice, hence the two starters. I can get the car to turn over by applying power to the s circuit wire, ipdm wire 30 has constant voltage no matter the clutch condition this led me to replace the ipdm. with the "new" ipdm, wire 30 still does not change state. I have put a jumper across the clutch safety switch to rule that out as well.

I have bench tested the relay, it works. I appreciate the help.

 

If wire 30 doesn't change state remove the harness and test the actual clutch switch to make sure it's functioning properly. I suspect that's where the problem is.

 

just removed it and tested it, the clutch safety switch is working properly so im guessing check harness between switch and wherever it goes too ?

 

all though I get a click like it tries to crank, when my clutch safety switch went on my 2003 350z it wouldn't make any noise or attempt to start what so ever

 

If there's a click that means not enough voltage/current going to the starter to actually crank the motor. Clean up the cable terminations really well, inspect the full length of the primary cable for any damage even a pinhole can completely rot out the copper inside the cable. Throw a charger on the battery to make sure it is fully charged.

Something is causing not enough current to get to the starter it sounds like.

You can also disconnect the signal cable from the starter solenoid and test with a meter or test light to make sure it's getting power when you turn the key to START, I'm betting you have voltage.

 

Did you ever test the two batteries and how did you test them?
Just measuring voltage across a battery is not sufficient.
Go spend 10 bucks on a battery Hydrometer and test each cell.


If you have a sealed battery you will need to take the battery to a shop that can do a proper load test

 

i took both to autozone to get load tested, and then had them charged. one resides in my 350z which is a daily so I know for a fact that's a good battery

 

I have battery voltage with key on. when I go to start it drops to around 5v

 

That's pretty typical of a bad battery.

 

I have a 500cca battery that starts other vqs its not the battery and I have jumped it with my truck

 

A 500cca battery is not a sufficient capacity battery. If the voltage drops to 5v when engaging the starter your battery has either a dead cell or insufficient charge capacity.
Replace your battery with a new 700- 850 cca battery.
Make sure your battery cables are clean, tight, with no corrosion.
What is the date code on your 500cca battery?

 

the date code was not punched on my battery sadly. would jumping the car to a running vehicle still not supply sufficient power because even when being left on jumper cables it still clicks

 

If your battery has a shorted or dead cell that is entirely possible.. You also may not have great jumper cables?
Swap batteries and see your vehicle will start with the other battery