VDC/SLIP/Speedo/Tach/Transmission and other electronic issues.

[dmitriylm]

I've had a bit of a frustrating day. I drove my car this morning just fine and later in the day when I started the car I noticed rough gear changing when going into drive or reverse. I then noticed that the VDC and SLIP lights were illuminated and I was really hoping that this was a low brake fluid issue but the fluid levels were fine. I started driving the car and the transmission was shifting gears with noticeable roughness, particularly the 1-2 and 2-3 shifts. Sometime soon the service engine light illuminated and I noticed the speedometer was reading zero. I decided to drive the car to the dealership and noticed on the highway that the transmission was rather busy, continuously up/down shifting and the tachometer was bouncing all over the place, not even seeming to be relative to actual engine speed. At some point on the freeway the transmission just allowed the engine to rev as if i was slipping and then power would come back and cut out. I took the next exit and by the time I was off I was pretty much limping along at 5mph. I would just rev without moving at every stop and by switching from drive, to manual, to neutral power would eventually come back for a short bit and then slip again (engine hit max rev's with ease). I noticed at the same time that when putting the car into manumatic shifting, the dash cluster did not register the change from D to M. My emergency blinkers were all over the place as well, the timing between blinks wasn't even and sometimes they would stay on longer than normal between blinks. I wasn't even sure if they were visible on the outside. Does anyone have any ideas? I've read a bunch of threads related to slip/vdc but none seem to have the transmission shifting and slipping issues. The car was towed to a shop and they did pulled some codes, something similar to "network communication error" and "speedometer module error".

[dmitriylm]

Here are the code details:

DTC: P0500

Search Bulletins/Recalls for P0500

Trouble diagnosis name: Vehicle speed sensor

Diagnosis Logic

The vehicle speed sensor is installed in the transaxle. It contains a pulse generator which provides a vehicle speed signal to the combination meter. The

combination meter then sends a signal to the ECM through CAN communication line.

DTC detecting condition:

* The almost 0 km/h (0 MPH) signal from vehicle speed sensor is sent to ECM even when vehicle is being driven.

Possible cause:

* Harness or connectors (The CAN communication line is open or shorted)
* Harness or connectors (The vehicle speed sensor circuit is open or shorted)
* Vehicle speed sensor
* Combination meter
_________

DTC: P1574

Search Bulletins/Recalls for P1574

Trouble diagnosis name: Automatic Speed Control Device (ASCD) vehicle speed sensor

Component Description

The ECM receives two vehicle speed sensor signals via CAN communication line. One is sent from combination meter, and the other is from TCM (Transmission

control module). The ECM uses these signals for ASCD control.

DTC detecting condition:

* ECM detects a difference between two vehicle speed signals is out of the specified range.

Possible cause:

* Harness or connectors (The CAN communication line is open or shorted.)
* Harness or connectors (The combination meter circuit is open or shorted.)
* Combination meter
* Vehicle speed sensor
* TCM
* Incorrect ASCD brake switch installation
* ECM

____________________-

DTC: P1212

Search Bulletins/Recalls for P1212

Trouble diagnosis name: ABS/TCS communication line

Description

This CAN communication line is used to control the smooth engine operation during the ABS or TCS operation. Pulse signals are exchanged between ECM and

ABS actuator and electric unit (control unit).

DTC detecting condition:

* ECM can not receive the information from ABS/TCS control unit continuously.

Possible cause:

* Harness or connectors (The CAN communication line is open or shorted.)
* ABS actuator and electric unit (control unit)
* Dead (Weak) battery


______________

Infiniti Number U1000
Type Network - Manufacturer Controlled DTC - Manufacturer Controlled
Description

CAN communication line - signal malfunction
Cause

Wiring

*TSB

______________

U1001

Controller Area Network (CAN) communication problem

_____________

All of the codes point to a CAN malfunction

[joe603]

Hang in there...we have a few really good Infiniti techs.

[SteveTheTech]

Typically CAN network issues are not for electronics rookies, this is one of the most complicated diagnostic procedures technicians have to perform. You will need to study the LAN section of the factory service manual.

I do not think you will be able to do anything other than guess unless you have access to a consult.

Since no two CAN problems are the same, and guesses are very expensive. If I had this car sitting in my bay in the morning I would start by checking the connector on the transmission and then figure out what happened to your VSS input.

Good Luck,

[dmitriylm]

Thanks for the reply's guys, I've got the car towed to a Nissan dealer a few hours ago and I'll see what they say. Could it possibly be an alternator issue? I say this because the car is now producing a slight whine while moving and one of the techs stated that it could be the alternator (hopefully its not the transmission making the noise). For the past several months the car has also been emitting a ringing noise whenever the lights are on. Could this all be connected?

[dmitriylm]

The dealer claims that the transmission is gone. Does this sound likely for all the electrical problems? If this is correct then I will begin looking for a used transmission and have it installed at a friends shop.

Are same year 350Z/G35 transmissions interchangeable? Is it plausible to replace the AT with a 6MT or would that require far too much work?

[joe603]

This is the first AUTO tranny that I've heard of going bad! Seems odd that it would shift fine...

I'm fairly certain that the 350z tranny is the same as the G35. However, to do a swap would be very expensive as the main ECU and harness needs to be replaced. I've seen it done (and done right) for 10k.

There is another member that recently purchased a used tranny here on NICO.

Gwoods, can you help out Dmitriy?

[gwoods]

car-part.com is a auto recyclers ebay/craigs list. I found mine on ebay for $100, it was $1500-$2500 on car-part.

I bought mine for the day you just described. I doubt your problem started out as a bad transmission. It sounds like you had some sensors that failed or shorted. Driving the car with it malfunctioning could have ruined the transmission in my opinion. When the slip vdc and service engine soon light comes on that is your signal to call for a tow.

I would get a second opinon on that diagnosis. Try an Infiniti dealership.

Have you kept the transmission serviced? On the 07+ the book says change the fluid every 30k have you been changing the fluid?

[SteveTheTech]

I am very skeptical that this CAN related issue has its routes in a mechanical failure. Although it is not beyond reasonable assumption that a transmission could very well fail I think at worse the TCM (in the pan) would need to get replaced. Replacement of the TCM also replaces the valve body so the only real repair the RE5 can realistically have done. I am not a huge fan of repair shops taking it too the RE5 unless it is from one of the approved reman facilities (exchange program). Mechanical failure is not common at all and I would be unlikely to accept their condemnation without concrete proof. Your hour diag time should get you a little concrete proof to justify replacement of such an expensive component.