04 350z problems (nats maybe, dont know)

[jonvia1234]

This is going to be a long post, so I apologize in advance. Have a 2004 Nissan 350z drift car, long story short, car needed parts fixed (angle kit, new front fender etc) Car has been sitting on the trailer waiting on parts. Parts finally come in, a few weeks later. Same day we go to start the car because it hasn't been started in forever. Starts no problem. Get to replacing the pass front fender, finish up the angle kit parts and bam no crank no start. Security light full red. Car hasn't even moved off the trailer mind you. Try to hook up a scan tool and no communication at all. (tested scan tool on other vehicles, works fine)

okay, so things we have done/tested: new starter, tested for power at starter wire (12 volts), replaced IPDM box, check every single fuse in every fuse box, replaced BCM and footwell fuse box to see if it would at least let a scan tool communicate, removed engine grounds and sanded/wire brushed them, did the "escape lock mode" key thing, battery is good, tried jumping battery just in case, swapped relays (ecu relay and etc), checked for loose connections under car, sent ECU off to be tested, came back as good and communicating said no codes were present, replaced NATS antenna, jumped clutch switch wire nothing, tested resistance on pins 7 and 14 on the obd connector, no short circuit, passed test. Took it to Nissan dealer couldn't get their tool to read either.

My ultimate question is, if the security light is on, will it disable CAN communication completely? Been looking over wiring diagrams/forums and cant get a direct answer. Our next step is to send the ecu off to have NATS deleted. Any input would greatly be appreciated, we are going insane trying to figure it out. Please send help lmao

[VStar650CL]

Is it an '04 or '04.5? The cutoff is:
Coupe From D*4T180001, E*4T080001
Roadster From D*4T110001, A*4T010001

In either case, if there are no codes in the ECM then the sec lamp and no-comm are because the ECM isn't waking up. There would be P161x codes in it if something else was causing the lamp. The ECM has to wake itself up by way of the ECM Relay, it's configured that way so it can self-awaken while the ignition is off to check the gas tank and evap integrity. So the problem could be anyplace in the power path from the ignition switch to the ECM Relay. If there's power at the "EGI" fuse in the IPDM, then you have to make sure the ECM is getting an ignition signal so it knows to turn the relay on, and if so, is it actually driving the relay coil? Start by seeing if you have power at the IPDM wires that feed the ECM when you turn on the key.

BTW, when you say you checked all the fuses, did you check them by sight or with a test lamp? Sight checks are useless, they don't tell you if the fuse has power.

[jonvia1234]

Is it an '04 or '04.5? The cutoff is:
Coupe From D*4T180001, E*4T080001
Roadster From D*4T110001, A*4T010001

In either case, if there are no codes in the ECM then the sec lamp and no-comm are because the ECM isn't waking up. There would be P161x codes in it if something else was causing the lamp. The ECM has to wake itself up by way of the ECM Relay, it's configured that way so it can self-awaken while the ignition is off to check the gas tank and evap integrity. So the problem could be anyplace in the power path from the ignition switch to the ECM Relay. If there's power at the "EGI" fuse in the IPDM, then you have to make sure the ECM is getting an ignition signal so it knows to turn the relay on, and if so, is it actually driving the relay coil? Start by seeing if you have power at the IPDM wires that feed the ECM when you turn on the key.

BTW, when you say you checked all the fuses, did you check them by sight or with a test lamp? Sight checks are useless, they don't tell you if the fuse has power.

It is a coupe, the year as far as an 04 or 04.5 I'm not sure, its my buddies car. Ahhhh okay, that gives me a better understanding on how the system works. I will do those tests next. So to test power to the relay, all I need to do is use a multimeter to test voltage directly to that relay via whichever pin is the direct battery source, then test power going out to ecu via the wiring from the ipdm? I'm awful at electrical stuff tbh. Yeah I checked them by looking. I probably should have used a meter or test light for sure. We used the fuses in the new (used) ipdm module though, what are the odds the same exact fuses could be bad? Guess at this point anything is possible though.

[jonvia1234]

I find it so odd that all of a sudden a wire connection/relay or fuse would just go bad from the car not even being used though. That's the mystery of the security light, and if it is on, will it cut communication to the ecm because its a security issue? My buddy jumped the gun and is sending ecu out to get nats deleted anyways just so there isnt issues with it in the future.

[VStar650CL]

I find it so odd that all of a sudden a wire connection/relay or fuse would just go bad from the car not even being used though. That's the mystery of the security light, and if it is on, will it cut communication to the ecm because its a security issue? My buddy jumped the gun and is sending ecu out to get nats deleted anyways just so there isnt issues with it in the future.

Getting the NATS deleted will probably be a vain exercise. With no NATS codes in the ECM, it means the lamp is coming on because the ECM isn't waking up, not because there's a problem with the key or the IMMU. What you need to figure out is why the ECM isn't waking up. Since you changed the IPDM, chances are the issue isn't a bad ECM Relay. I can tell you how to test it, but I'm not sure if there are any differences in the IPDM between the '04 and '04.5. So to keep both of us from chasing our tails, get your buddy's VIN and find out for sure what the car is.

[jonvia1234]

I will get the exact year within a few days. So that would explain the no communication and also the cel light not even coming on before you try to start the car.

[jonvia1234]

Vin is JN1AZ34D64T151098 so that would indicate an 04 and not 04.5 right? We are going to be taking the car to a friend of mine who has been a technician for different auto manufacturers over the years. I will relay any information from this post to him so he can be checking. I'm also going to dive into the Nissan repair manual and see what else I can come up with. Any input will be greatly appreciated.

[VStar650CL]

Vin is JN1AZ34D64T151098 so that would indicate an 04 and not 04.5 right?

Correct.

Check out EC-129 here for the ECM power scheme:
https://www.nicoclub.com/service-manual ... r%2FEC.pdf
You can see the IPDM layout here on page PG-22:
https://www.nicoclub.com/service-manual ... r%2FPG.pdf

Checking at the ECM, you need to see the key-on ignition signal at pin 109 White/Black. Without that, the ECM won't try to wake up, and the likeliest culprit would be a bad ignition switch. If that's good, pin 111 Grey/Blue should go from battery voltage to ground when the key is on. If there's no Vbat when the key is off, then there's a break in the circuit between the ECM and the relay coil in the IPDM. If there's no ground with the key on, then either the ECM relay driver is bad or pin 111 has a bad pin fit. If that all checks out, then test pins 33 Red/White and 35 White/Blue at the IPDM, they should both go to Vbat when the key is on. If they don't, then something is wrong with the relay or IPDM despite them being new. If they do, check pins 120 Pink and 119 Red/White at the ECM, they should both follow Red/White at IPDM 33. If one or both don't, there's a break in those wires between the IPDM and ECM. If they do, check pin-fits on 119~120. If both are good then the ECM has what it needs to wake up but isn't waking up anyway, so start checking the ECM grounds.