Car will not start after tuning

SonicVQ

Sorry for misunderstanding about the starter wire.
It sounds like the fuses, power and wiring are ok...

Does the BCM code B26E8 still come back after clearing it?
The FSM is states (2016 370z BCS-98) that a B26E8 code will "Inhibit engine cranking"

ShadowJester6

No problem. There's so much going on in this mess of a starting system. I am constantly second guessing and rechecking everything over and over.

The code does return. FSM says that it is the clutch interlock switch. Unfortunately, I believe this to be one of those very vague codes that could be many different issues. If you trace that schematic, I've traced the 12V from the battery, through the clutch interlock, through the BCM, to the IPDM E/R fuse box, and through the fuse box up until the starter control relay (which is not closing as it is not receiving the necessary signal to close the relay). I believe the code is being thrown because the starter control relay is not receiving the signal to shut. Unfortunately, I have no way of knowing where and why that signal is being lost.

redondoaveb

Have you tried to bump start it or with the electrical fuckery going on you don't want to try that?

__________________
Fast Intentions "Stage Seb" twin turbo #098- Specialty Z/Tial-Xonarotor/CJM/Ecutek/HKS/KW/SPL/Hotchkis/Rohana/Toyo
750whp/700ft.lbs

Spooler

You have a stumper going on. I have dealt with one like this. It was a burn't connector in the main harness. You will need to trace every wire going to and from the clutch inhibitor switch at the clutch pedal and ohm them out. You can try to jump the switch and see if it will crank that way.

SonicVQ

I think the DTC name: "Clutch interlock switch" may be misleading...
What if the ASCD / cruise control clutch cancel switch is sticking for 2.1 seconds???

When you read the DTC detection condition is says:
Detects that ASCD cancel switch is in the ON position for 2 seconds or more while ignition switch and clutch interlock switch are ON.

This is saying the ECM can't verify clutch pedal position, because both clutch pedal switches are ON.

The "ASCD cancel switch" (which is also called the clutch pedal position switch) is on the clutch pedal and is closed when the clutch is fully up. This is the switch that turns off the cruise control when we tap the clutch pedal.

As you know, the other clutch pedal switch is closed when the clutch pedal is fully depressed. This is called the "clutch interlock switch"

To test:
• unplug the ASCD cancel switch (this tells ECU that the clutch pedal is not at the top)
• unplug and short out the clutch interlock connector. This tells the BCM that the clutch pedal is at the floor.
• make sure the car is in neutral and/or press the clutch down
• try to start the car.

I had a similar issue on a Mazda 3 and the fix was to replace the switch... What was VERY interesting is that the switch was made by Nissan!

ShadowJester6

I don't know if I mentioned it before, but I've done that test as well. I hit the start button without touching the clutch to turn "acc" power on which will wake up all the computers and let them know it's go time. I then unplug the cruise control switch and left it to simulate the clutch pedal leaving breaking the circuit. And finally, I unplugged the clutch interlock switch and jumped it. No change. I then used the start button to cycle power a few times as I heard rumors of there being a time limit between all of the switches opening and closing. Still nothing.

SonicVQ

Crap!! I was hoping for better news.

The next step is to view what the BCM "sees" for the clutch pedal position.
Luckily, this doesn't require a Consult III+, but just a a cheap OBD scanner ($20), OBD Fusion ($7-14) and their $14 OEM Diagnostic add on.

With this app, you can connect to the BCM and view the clutch pedal switch status. You have checked the switches, BUT that doesn't mean the BCM sees the required criteria to crank/start the engine.

Here is a screen shot from my G37 Sport (6 speed manual) with the clutch pedal on the floor and fully released.



Any interest in pursuing this?

Attached Images

1.jpg (101.1 KB, 135 views)

ShadowJester6

I need to check my setup up to see about the cruise control, but I have done that test with the clutch interlock. Using a laptop and the tuning software, I can watch the clutch switch being toggled in real time. So as far as the clutch interlock is concerned, the ECU and BCM both see that the switch is working as intended, which is part of my previous thoughts about the DTC being thrown actually being a generic error.

I'll report back when I check out the cruise control switch through OBD. I don't know if the app I'm using or the tuning software I have tracks that. If not, I'll look into the app that you have.

ShadowJester6

Well, car is still an expensive but useless hunk of metal and plastic.

Verified that the both clutch switches (interlock and cruise control) toggle as expected through tuning software.

Also verified that the U1000 and B26E8 codes keep returning after resetting ECU while I was in there.

I tried different variations of unplugging the cruise control switch and jumping the clutch interlock. No change as expected.