I bought my 2003 G35 Coupe 6MT used in 2006 from an Infiniti dealership. I have had this problem intermittently since then. Here's what has been happening:

After driving in heavy rain, the next time I try to drive the car the VDC and Slip lights come on, the Speedo does not work at all, the Tach decides to work intermittently when it wants (drops to 0, then jumps to correct RPMs), and it takes a while for the temp gauge to register and when it does it just jumps up to normal running temp.
Other than that, the car seems to drive normal.


Some of the times I have had the following happen, but not every time:
The passenger headlight will flicker on and off.
I will hear a clicking coming from under the dash with the car turned off keys removed.
When the car is parked, keys removed, alarm set, the battery will drain somehow, causing the alarm to eventually go off (in the middle of the night ), and the car will not be able to start. It will eventually need a jump start.

The problem in diagnosing this, is that all of the symptoms go away after the weather has dried up some, and thus clears any codes that are being thrown. I've had it to the dealership a couple of times, and even running it through the carwash for 30 min. they are not able to recreate the issue

I was FINALLY able to get it to a dealership while it was experiencing these issues. They pulled the following codes:

P0500 - Vehicle Speed Sensor Malfunction
P1212 - ABS / TCS Communication Line
U1001 - CAN Communication Line

They are saying that I need to have the instrument cluster replaced.
Does this sound right?
(luckily I have an extended warranty)

The only reason I ask, is becuase this only happens when it rains. So I would think it would be something external that could get wet. I would also think that it would be something shorting out with the ABS Control Unit due to the P1212 and P0500.

I also saw someone post this in another thread regarding speedo/tach malfucntion:
which could explain why they think that this is something in the gauge cluster.

I have done EXTENSIVE searches and cannot find something exactly like my case.

Any thoughts?

(Sorry for the novel, but thought I needed to be as detailed as possible with this one)

 

u sure your ECU or BCM arent getting wet?
seems like an obvious question though...

 

Perhaps your car was in an accident before. Maybe the wire harness on the passenger side that goes through the firewall is getting wet...first place I'd check is that seal under the wiper cowl.

 

Thanks for the response and bump.
I've checked for water in those areas, and don't really seem to find any. I'd also find it really hard for water to get to either of those units being inside of the car, although crazier things have happened.
I haven't been able to get back to the IPDM yet though and I'm going to try to over the weekend to see if anything "sticks out" there.

 

Even though there's always the possibility, I highly doubt this car was in an accident. I mean, the Carfax was clean!!! (jk jk jk ).
Anyway, I'm definitely going to chekc the wire harness on the passenger side that, I think, goes to the IPDM into the passenger side control units. I'll also be checking the seal under the wiper cowl (good call).

 

Bump!!

 

So, I took it to the dealer and they replaced the instrument cluster last week.
On the drive home all of the symptoms came back. I called and they said to bring the car back in this week.
I just got a call and they said that the instrument cluster that they put in had a problem with it, and they have replaced it. They also said that it's throwing new codes:
P1212 (not new) and P1124.

They're saying that I need to replace the ABS Control Unit and the IPDM. This would not be covered under the extended warranty and the quote is $2400. Needless to say, I don't think that is the problem at all.

I'm thinking there is a short somewhere and am going to be looking at the IPDM to see if there's any water getting there.

Idea's are welcomed.
I'll keep people posted on what's up.

 

I'm having a very similar issue to this. My speedo works fine tach is totally dead and so is the temp gauge. Also sometimes it starts sometimes it doesn't. In addition, occationally the headlights do their own thing and when this is going on, nothing on the steering column works (wipers, lights, blinkers). AND the TPMS light comes on from time to time, and it is acting like a limp mode indicator (when it's on, car in limp...when it off, no limp.) BUT! it works fine sometimes (still have VDC, slip, no tach and no temp but runs normal other than that.)

It has been raining HARD for the last 3 days so I'm thinking that the IPDM is getting wet and causing this. Also, checked and I have a P1124 throttle relay shorted. Pulled snap data from the code fuel trims 1 and 2 are normal....3 and 4 tho (didn't know those existed are at -100.6%) Also scanner says MIL is on.....it isn't. :/ help plz..haha

EDIT: this just started today and I figured all this out in like 2 hours

 

BUMP
BUMP

I having the same exact same symptoms. Was the issue ever solved and if so how. Thanks

 

It stopped raining, i let it sit and dry, parked in the garage at work dry some more...it was fine, as been ever since. Rained hard again for the last 5 days and no issue. For me it was the IPDM got wet through a massive puddle and just had to dry. If it dries and is fine for you also, be more cautious of those big puddles. Hope that is the case with you also.

 

Thanks buddy, as a matter of fact that’s word by word what had happen to me. It's been raining pretty badly and I remember one puddle in particular that might have done the trick. None the less I took out the battery to get better access and there was about an inch of water. I remove the plug in the bottom under the battery tray (which I drilled two holes in) cleaned all the dirt out and blow-dried the IPDM. Next morning she fired right up.

For future reference my symptoms where as follow-
-headlights randomly turn on and off
-car would crank but not start
-bose head unit sound like it wanted to eject a cd
-slip and vcd light’s on.
-with the key turn on "ON" the fans would kick in
-when I would lock the car the panic would go off

Watch out for puddles or just rain in general. Everyone should look in their battery area every once in a while to see if water is collecting.

Again, thanks Shakuya88

 

I've heard of this happening to people. Water getting down into IPDM as also heard of water leaking down into the passenger foot area (where the ECU/TCU are). Remove all the plastic cowling above the battery area and inspect for water.

 

wow, i just now have the same problem. but i dont know if its rain or anything. my speed tach doesnt work, hot/cold tach doesnt work, my rpm shifting very weird. my VDC off is on. the "slip" is on. the service engine soon is on. when i drive, it shifts very weird.. any clue?? my car is an 2003 coupe/automatic. sighhh

 

Check what codes are coming up. It's just a wild guess but I bet you might find P1124.

GoodLuck

 

if i find a p1124 code, is that bad? what is it?

for some reason i started up the car this morning, it everything seems to be working fine, shifting is accurate, speed tach/hot/cold tach is fine, only thing lighting up is "service engine soon"