About a week ago I failed emissions because of my CEL. I checked the codes and found Knock Sensor and EGRC Solenoid. I replaced the solenoid and still got codes Knock Sensor and EGRC Solenoid, but then a new code popped up as well. It was 0804, A/T Control Unit, but I have a manual transmission. I thought maybe it was the Knock Sensor. I replaced the Knock Sensor today and I am still getting all three codes, Knock Sensor, EGRC Solenoid, and A/T Control Unit. I checked the KS and I'm getting 555 Kohms. I'm wondering if there is a fuse or something on this circuit that would cause all these codes to go off. Anybody with any ideas (or a Factory Service Manual) please post. Oh, I also have a JWT ECU and a service tech at Nissan told me that it could be because "someone" changed my ECU.

 

0804
Diagnostic Trouble Code 0804 is detected when the signal from the Transmission Control Module is not sent to the Engine Control Module. The factory service manual identifies these possible causes:
- Harness or connectors (the communications line circuit between ECM and TCM is open or shorted.)
- TCM
- Weak or dead battery



1005
1005 is EGRC Solenoid valve

The majority of my information about Diagnostic Trouble Codes comes from my '99 Maxima factory service manual. Unfortunately, DTC 1005 is not in that book. Starting in '99 the Maxima engine uses a step-motor type of EGR valve and with that change, the DTCs changed.
The Chilton and Haynes manuals provide a little information about the EGR Solenoid Valve.
The test procedure for this part is found in the Chilton repair manual (page 4-11) and the Haynes repair manual (page 6-20). Test the valve and replace if necessary.

This malfunction is not an emergency but should be resolved fairly soon (7-10 days). An inoperative EGR valve may result in engine pinging and a variety of driveability complaints.





Reset ecu again and see if the codes come back.

 

I reset the ECU and drove around for a bit and found that the KS code is gone now, but the A/T Control Unit and EGR Solenoid Code are still coming on. I have already replaced the solenoid and checked for signal coming to the wiring harness, I am really at a loss as to what else to do. It looks like there is a fuse harness in that area, any idea if that is for the EGR Solenoid?

 

http://forums.maxima.org/showthread.php?t=295591



Also look at teh online Chiltons Manual (link in the FAQ's) for more info. Or go buy a haynes manual.

 

Anyone know what a box outlined in dashes with the label J/C stands for on a wiring diagram in the haynes manual?