Nissan Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
Had my transmission replaced a few years ago on my 2007 Nissan pathfinder it runs good with over 200k mN9neiles on it except when I put a load on the transmission if I pull anything or travel into the mountains it will go into safe mode and throw a u1000 code already had grounds cleaned didn't fix problem I did notice when it happens I smell hot transmission fluid is it possible trans fluid is overheating the transmission guys I had do the work bypassed the radiator and put an air cooled trans cooler in. I can't figure this out lol only happens when I work the transmission any ideas? Oh and after about 15 minutes it exits out of safe mode on its own
 

·
Sup Mod keeping the peace
Joined
·
6,895 Posts
A U1000 code is set when the ECM is not transmitting or receiving CAN communication signals of OBD (emission-related diagnosis) for 2 seconds or more. The possible cause may be a defective harness or connectors (CAN communication line is open or shorted). It could also be caused by the overheated ATF affecting the CAN lines in some fashion.

Why did the mechanic bypass the radiator? The air cooled trans cooler may not be large enough to cool the ATF when running under heavy load. The proper way to connect an auxiliary trans cooler is in series with the radiator.
 

·
Registered
Joined
·
2 Posts
Discussion Starter #3
The mechanic bypassed the radiator in order to resolve pathfinder issue with transmission fluid. Mixing with radiator coolant I was assured that aircooled trans cooler roughly 12"*12" was from a F150 would be sufficient to cool my transmission. But only when I put a load on tranny is when u1000 happens I can drive my pathfinder for so far thousands of miles on flat and even light graded terrain with no issues but if I climb 1 or 2 k in elevation to quickly or put a trailer on she shuts down
 
1 - 3 of 3 Posts
Top