Since grounding issues seem to be common on the MO, and the answers are spread all over the board, I made a thread specific to the U1000/U1001 Diagnostic Trouble Code (DTC).
Usually this ends up being a loose grounding bolt holding the ECM to the dash bar, causing the ECM to lose ground temporarily.
Many with this DTC complained of hesitation, stalling or the engine holding a lower than normal RPM. For me, I was cruising at about 45 MPH, the engine dropped to about 500 RPMs, began shuddering, and the SES light came on. The engine did not respond to the gas pedal and at about 15 MPH it stalled. I got over to the shoulder and tried to restart but it did nothing. It was like when you try to start with a completely dead battery; no sound. But I had full electrical power since the lights/radio/air was on. 5 minutes later, it started back up as if nothing had happened. Check Engine light remained on, and until it was looked at by a mechanic was a bit hesitant during acceleration.
Had my mechanic retighten the various connections. He left SES light on (didn't clear code). That way if he didn't fix the issue, a dealer would have the code to go by (dealers won't take your word, they need the code). About a week later the SES light turned off and the issue has not returned.
Relates to DTC U1000/U1001
"CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are conected with 2 communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only."
DTC Detecting Condition
-ECM cannot communicate to other control units.
-ECM cannot communicate for more than the specified time.
-Harness or connectors (CAN communication line is open or shorted).
When an issue with the CAN arises (at least twice in one trip), it triggers the Service Engine Soon (SES) light on the dash.
TSB EC06-001A Actions
When this code is brought on by a grounding issue, these are the steps the mechanic will follow to remedy.
-Clean/re-tighten ECM ground connections.
-Clean/retighten negative battery cable body connection and battery post connection.
-If needed, clean and ensure good contact between the steering member assembly and the left side instrument stay assembly.
Originally posted by vistokid
"Found U1000 Can Com code. This code is caused by ECM not getting proper ground. This is due to ECM is grounded through dash bar to vehicle body and bolts connecting dash bar to body become loose and ground is temporarily lost. Retorqued bolts and erased code light."
Misc Charges $11.24
Originally posted by njjoe
I had the C1000 (same as U1000) grounding problem three years ago. The fix was simple (tightened a grounding bolt under the dash) and took less than an hour. My records show they implemented Service Bulletin #EC06-001a... I was a bit skeptical when they claimed all they did was tighten a ground connection, so they printed out the SB as proof. The problem never returned. It was repaired under the bumper-to-bumper warranty.
Originally posted by PearlMurano
I went to Nissan today and they checked the SES code. Turns out it was code U1000 communication failure, ECM ground failure. They removed the dash and cleaned contacts at ECM and harness and secured connections. All is going well so far. Seems to have fixed my problem. Tech said that the murano was well known to have electrical problems of this type.
This should be covered under the 3/36 bumper-bumper, although you might have to fight for it. This is NOT
covered by the powertrain warranty.