99 Nissan Altima no communication
Hello guys I had a quick question and wanted to get a few opinions. I have a 99 altima that came in for fail emissions. It has no communication with ECM on the DLC. It looking like it is going to need a ECM. But during my findings I notice the wires in the DLC do not match the pin location as the diagrams I have seen state. Per the diagrams i have found the pin locations are Pink pin 1, Blue/black pin 10, and 2 blacks at 12&13. The way they are set up in the DLC on the car is pink pin 16, blue/black pin 7, 2 black at 4&5. I was wondering if anyone has seen this or can confirm what is correct. I cant imagine someone de pinned the connector for some odd reason and then just put them where ever but if they did maybe this is what damaged the ECM once someone plugged in a scan tool.
I have seen other cars where the SI had the connector pins labeled 100% reversed. It sounds like you are looking at that.
Either that or he is thinking it is showing the front view and it is actually showing the rear view of the connector.
That is what I figured since its kinda hard to believe that someone just swapped the wires around. Thanks
Lots of manufacturers have reversed DLC terminal IDs. The blue/black line is ISO 9141, and is your generic communications line (you are using generic menus, right?). The Pink one should have power (all times) and the other 2 should have ground. If OK, then the voltage should be checked at the blue/black wire. Lab Scope is best. The first ATS EScope capture shows the voltage jumping and then
Thanks for the info and the captures. Another tech tried multiple different scan tools on generic, with no luck. I check the voltage out of the pcm and I have less than 1 volt. I wanted to see if it was shorted to ground and It seemed it was so I cut the wire at the pcm to make sure it wasn't in the harness. It still was grounded. Thanks for the help
Do not forget you have two connectors on this vehicle. Your common DLC is for Generic Scan Data only. You will need a factory Nissan Connector to view OE scan Data. See the attached picture. The colors you have mentioned are for the generic OBD2 DLC only. EDIT: I do see what you mean by pins not lining up with diagrams, In the mean time, try communicating using the OE connector,
All year models state that the generic DLC should have a pink wire pin 1, a Blue and Black at Pin 10, and a black at both pins 12 and 13. That is what Nissan states for years 98, 99, and 2000. The Mitchell, Motor, and Nissan wiring diagrams all agree. The DLC PIN numbers are the same (see attached picture). From the attached picture provided from Nissan it appears the pins are reversed (mirrored).
Thanks for the reply. It does have communication on the consult (OE) connector. But since it is a OBD2 car for state emissions there has to be generic communication on the DLC and it does not have that.
Chris, I would check for short to ground or B+ on the KLine (Pin 10 Blue / Black). It is common for aftermarket radios and accessories to be tapped into the communication lines by mistake. Use a scope or ODB2 breakout box to look for activity on pin 10. If no activity, you could use a test lead to jumper from pin 58 on the Engine ECU to see if communication is possible. If there are no shorts or
Hey Michael thanks for the reply. I cut the wire (pin 58) last night at the ECM just to make sure that nothing was pulling it to ground. It is still being pulled to ground after it was cut. So I am also thinking the Kline is dead. I just wanted to make sure someone didn't mix up the pins in the DLC and cause this to happen. Thanks
I have seen some scan tools take down the leg for communication to the ECM on the 1999 and 2000 Altima's just trying to communicate.. A battery reset. holding both positive and and negative together for 1 minute. Resets and all of a sudden the vehicle starts talking again. That the vehicle came in for failed emissions i would gather it was running at the time you got to this vehicle?
Thanks for the reply! Yes this car runs find it does have a knock sensor code that I retrieved from the OE connector. But the only complaint was no comm on DLC and it failed emissions for that. I will try that reset and see what happens. Chris