I have a 2003 G35 coupe that one day while it was raining I went to the store and the car has started since. When I put the key in and turn to the on position the headlights come on and the radiator fan as well. I tried using a code reader and it doesn稚 read I致e checked everything to see if anything was wet and it also seems to loose communication when doors are closed. Please help losing my mind

 

Check the connection for the battery terminals.

Since you know it was LIKELY related to the wet weather remove the IPDM, take a picture of all the fuse and relay locations, remove everything, disassemble the IPDM, see if there is moisture inside.

If so put it in a bag of rice (along with all the fuses and relays) for 24 hours to absorb as much moisture as possible, reassemble, cross fingers it still works.

A common cause of IPDM flooding is the drains in the battery compartment being clogged up which allows water to pool up in the battery box and flood out the IPDM.

Other questions, does your tachometer move while cranking the engine, if not you might have a failed CKP sensor.

While cranking is the NATS LED indicator (security) on the left side of the dash SOLID RED? If so the vehicle may have lost the programming for the chip in the key.

 

Also when I say "disassemble the IPDM" I mean COMPLETELY disassemble all the way down to it's circuit board, there are internal relays that may be wet.

 

ok I知 about to head to the car and try that. Also I do remember the first thing to happen was the fob stopped working

 

I would start by checking that NATS indicator LED and seeing if the tach moves while cranking the engine.

Also something else I forgot, how much gas is in the tank, it's VERY common for the gas gauges to fail on these vehicles and read 1/2 tank when it's actually 100% empty.

I don't think these two things will be the issue since you are also having the "fans come on high speed when I put the key to the ON position" and that's a common symptom of a failed/wet IPDM. Headlights on could be the IPDM as well, especially if turning the headlights to the OFF position doesn't actually turn them off. The relay that controls them is in the IPDM and it could be wet as well.

 

would that also cause the ecu not to be read by code reader

 

Yes since one power source comes from the IPDM. You should also check your fusible link just to make sure it doesn't have a blown fuse for the ones that power the IPDM

You can trace out the wires on the service plug, I think there's only 5 wires on it, ECM power, IPDM power, ground, ground, k-line.

FSM section EC - Engine Controls, it's like 2nd or 3rd to last page in the document.

Fusible link holder slots are in PG - Power/Grounding, pictures of the link are near the very end of the document.

 

do you think there痴 a chance the ecu could be fried

 

There's always a chance yeah, but troubleshooting is usually free and will help eliminate other possible problems which are typically cheaper than an ECM replacement.

 

NATs is not ECU related its BCM.. so telling Op that ECM is fried is just kinda crappy. The scan tool your using most likely isn't compatible with your G most cheap ones aren't. Even in a shop. only certain ones will work. Infiniti shop will either use a Autel or like I use datascan hasn't failed plus datascan II full functionality.

1. find your bcm serial and pin that is calculated from you bcm serial
2. Don't buy off of Ebay unless you verify parts come from genuine sellers nothing junked. might as well pay good for a newer part your installing.
3. Disregard Ebay just buy OEM part.

Remember to erase all codes once problem is fixed. No start Nats condition happens the first or second time you start after ECM change its sort of random in a way, bs if you ask me


By the way you can find new ECM cheaper than dealer quotes same way they find for you.

 

I don't think you actually read this thread, as discussed earlier he probably had a failing IPDM since his fans are locked in high speed when he turns the key to the ON position with the engine not running, plus yes we already talked about a possible NATS issue since he has the solid red light in the on position. However the IPDM needs to be fixed first.

Yet he is also unable to communicate with the ECM so that could either be either of the two power sources, IPDM like I suggested is the issue, or the power / K-line from the ECM (or bad wiring) and I referred him to the correct section of the service manual to troubleshoot.

He asked if it's POSSIBLE that the ECM is fried and my response was.

I'm not sure how you read that as me telling the OP that his ECM was fried?

You only need the BCM decoded if you are using NDS2 (or Consult) to program the ECM to the BCM. He doesn't need to decode right now.

Any scanner will work as long as it has protocol ISO 9141-2.

Not trying to be an *******, I think there was just a misunderstanding of the contents of this thread.

 

Was actually on two threads at same time but mechs know typically service manuals only take you so far knowledge by concept really hits the nail on the coffin. But 👌I agree to disagree

 

I uhhhmm....

...ok?

 

thank you my friend I finally got it fixed it was a bad bcm. I wish I found out about it earlier but I bought another car