I've been dealing with an intermittent no-start no-crank for a while now, with a lot of downtime recently I figured I'd finally try and diagnose it.

Symptoms: When going to start the car, turn key to position 3, nothing happens. No attempt to crank at all. Key needs to be turned all the way back to position 0, then back to 3, typically several times, before it actually begins to crank. Sometimes this wouldn't happen for a week at a time, sometimes it'd happen multiple times in a day, seems to be more frequent lately. I've put an LED on the starter relay to see if a crank signal is being sent when this happens. During a no-crank, there is no crank signal sent, so it's (probably) not a relay issue. I've also tried swapping the relay, again nothing.
When this happens I can't see any error codes. No dash warnings, no P-codes picked up by my PLX bluetooth scanner. I'm also pretty sure I don't see any flashes on the security LED by the J-gate when this happens, which is what I understand should happen if it's a chip read issue.
I've been trying to get a VCM working on and off for a while now, but haven't quite gotten to the point of being able to read codes. Hoping that would tell me something the OBD scanner couldn't, but, still not there yet.
I tested the ignition switch resistances (all good there), and inspected the BPM soldering joints. Nothing obvious there either.
Oh and the battery is fine. I have noticed there may be an intermittent drain too, haven't been able to figure that one out either since it's infrequent. That will be looked at deeper when I'm doing my transmission.

While a BPM isn't too expensive, I don't want to go down that road unless I can eliminate other possible causes and say it's a deeper fault in it for sure.

Any ideas what to probe next?

 

check the fake firewall ground on the passenger front side.

shake the jgate around till you hear beeps then try again

 

I think I might have tried the J-gate in case it was the park safety, and it didn't help when I did that. But I could be remembering wrong, I'll try that next time it happens.

Grounds are a good point, I'm hoping to go through to do a thorough check of the main grounds up there, engine ground strap etc, and the high current 12V line. I'll check the false bulkhead ground then too.

 

Since there are 2 micro switches in the J gate for neutral safety, maybe put the trans in neutral during the same time it won’t crank/start in park to see if that helps. Those micro switches can get dislodged from their bracket via loose rivets. Also the little arm from the M.S. that comes in physical contact with the chrome gear selector lever gets loose also.

Since you have an R car, there’s a “dual linear” switch (black rectangular box) mounted on the RHS of the J gate assembly. The transmission shift cable bolts to this box and does feed into the park/neutral circuits as well. The contacts inside the DL switch become dirty. Just take it apart and clean it up. I also use dielectric grease on the contacts inside. It’s been awhile since I’ve done this but, it would be helpful to use a scanner to make sure this switch is adjusted properly.