Hey guys so I've been having issues with my '03 350z for a couple of months now, here's a quick overview of what's been happening, sorry for the long read I tried to summarise it.

So I decided to do the timing chain as it was rattling on cold start, I finished replacing timing chains, tensioners, water pump etc. also changed throttle body, accessory belts.
Car started up & ran perfect for a while.. went for a drive and about 11km into it car bogged down & engine died. Wouldn't start for a while then started and ran temporarily as I moved it to a safer place to park it up. Had a mechanic diagnose it as old brittle MAF wiring, changed that & car started up & ran perfectly for a day or so...
This is when the car decided not to start & NATS light goes on solid when key is in ON position, thermo fans turn on full blast.
Scanned the car & got codes relating to ECM not communicating, from there I towed it to the local Nissan dealership. The technicians there spent a few hours here and there diagnosing it and determined it was either ECM or ECM relay. I replaced the relay & it started right up, temporarily.
A couple days later same issue. NATS light solid, thermo fans on full blast.
I then replaced the whole IPDM with a used one from a wreckers as that was $130 compared to $1,500 for a new one from nissan. Car started and ran perfectly, a few times... drove the car home & parked it up to do some other small maintenance & fluid top ups before getting back on the road.
Again.. wont start, NATS light on solid, thermo fans on.
I've tried fiddling with the key, tried the spare key, locked & unlocked heaps of times, disconnected battery & discharged it, I'm also having issue with my OBD scanner not connecting to the car but its a new OBD scanner and I'm unsure if its even compatible.
Going to get a friends OBD scanner which works on his 350z on it in the next few days & see what happens.


possible causes?:
NATS
Fuel Pump
Cam & Crank position sensors?
Bad wiring to IPDM or
bad IPDM itself (unlikely?)

I cannot for the life of me diagnose this properly and it's doing my head in. Anyone able to help?

 

Wow, that's a LOT of moving parts- timing chains, throttle bodies, brittle wiring and more. Hopefully someone will chime in with some insight or advice.
Welcome!

 

Why did you change the throttle body?

 

About a month or so prior to all this I got a code & limp mode for throttle control motor relay or throttle body itself so I replaced both.

 

Can someone please shed some light?

 

So today we got an obd scanner to work with the car, the codes we got are:

U1000
C1136

so at this stage I’m thinking maybe blown ECM?
the obd reader was still having trouble communicating.

anyone able to help?

 

You check BOTH ecm fuses and the relay?

 

Hey guys here’s another update,

I had the old ECM relay so I swapped it out & the obd reader finally cleared the codes for me. The issue seams to be gone for the time being but it’s done this before. Last time I swapped the relay it started and ran a few times then went back to doing the same thing.
I’ve also acquired some new “pending” codes being:
P0011
P0021

good times. For now though the car seems to start and run fine.
anyone know what to replace for those 2 codes? And whether them being pending or not matters?

Thankyou