98 Nissan Maxima ECU not responding after self-diagnosis. Turned screw on ECU to get error code via blinking service engine light . Turned light off. Noticed clock was no longer illuminated and after driving and turning engine off that trip odometer automatically reset to zero. Service engine light came back on before making repair. Asked AUTO ZONE to confirm diagnosis. Sales person said the computer wasn’t connecting to scan tool. I made repair, then disconnected battery to reset computer. Service engine light is off. Problem with clock and trip odometer remain. Computer still isn’t connecting to the scan tool. What can I try to get the ECU to respond before going to the mechanic?

 

Have you checked the screw on the ECU?

 

yes. the screw is back in its original position.

 

It could be in its original position but still be in diagnostic mode. Is the CEL blinking? Try resetting it again

 

CEL is not blinking.

 

its very possible the auto parts store guy doesn't know what he is doing. Go to another store and see if they can get it. Messing with the battery its also possible you blew a fuse. Check the fuses in the cabin and in the engine bay

 

Resetting the ECU doesn't appear to have changed anything. The clock and trip odometer problems remain. Haven't had the opportunity to try connecting scan tool. Will check fuses, but problems existed before disconnecting battery.

 

I have the same problem with my 96. I checked all fuses and made sure that the ECU was not in diagnostic mode. When I brought it in to get the ECU scanned the guy told me that either a fuse was blown or my ECU was gone. I purchased a new ECU and my clock light and ac lights still do not work, and car wont connect to scan tool. I have checked all the wires for shorts, breaks, etc and nothing. Not trusting the auto parts guy, I obtained my own scan tool and tried my self. If anyone can help, PLEASE give me some ideas.

 

There was a thread on this the other day, I think it turned out being a fuse since the clock was linked to the problem. Initially on my max I couldn't connect to scan tools either. Turned out there was a break somewhere in the data wire. If you have a chilton manual or some other manual with the maxima schematic you can trace the data wire from the obd plug to the ecu and check for continuity. I ended up running a new wire for the data and it solved my problem. I belive there is a power wire in the obd plug as well so the clock and such are probably on the same circuit.

 

Problem resolved. It turned out to be a blown fuse as suggested. Thanks for the help.

 

Which fuse was it?

Just asking so someone in the future who has this issue can figure it out.

 

Can't scan with most scanners, mac scanner ET1505ANX will work (brother inlaw has one) but out of my price range. Clock blinks in and out, and every once in a while when the passengers door is shut it triggers locks for all doors.
The MAC scanner and emissions test stations are able to scan but auto parts stores get no communication.
I haven't found any bad fuses.
Did I miss something?

Please help!

 

Pin 1 of the OBD connector should have 12 volts on it for use by the scanner device. Maybe the expensive scanners don't use power from the car.

Pin 1 gets power from fuse # 40 which is the one in the top right corner of the fuse panel. Check this fuse.

 

Quote:
Originally Posted by James74086
Can't scan with most scanners, mac scanner ET1505ANX will work (brother inlaw has one) but out of my price range. Clock blinks in and out, and every once in a while when the passengers door is shut it triggers locks for all doors.
The MAC scanner and emissions test stations are able to scan but auto parts stores get no communication.
I haven't found any bad fuses.
Did I miss something?

Please help!
Pin 1 of the OBD connector should have 12 volts on it for use by the scanner device. Maybe the expensive scanners don't use power from the car.

Pin 1 gets power from fuse # 40 which is the one in the top right corner of the fuse panel. Check this fuse.
-----------------------
Yes the fuse was bad. I originally thought it was just an LED not a fuse.
Last owner must have replaced it at some point. I still have the problem with the clock and doors, so I will jy for another clock and check my grounds for doors.

 

My apologizes for cutting in the thread without anything helpful to contribute I have a '95 with same issue and was wondering if anyone know what fuse that is that needed to be charged. Very humbly please help a guy out.

 

Here you go in this thread. Note this was on my 98 model.

https://maxima.org/forums/4th-genera...ry-solved.html

 

Recently hooked up my buddies snap on computer to my obd2 port and it comes back un able to connect. But my cheap scan tool that just gives codes works fine. Got state inspection next month and know they will fail me if the can connect. Has any one heard of this happening where the code scanner works but not a diagnostic device won't?