OBD 1605

Nissan Altima OBD code 1605

P1605 NISSAN - Automatic Transmission Communication

The 1605 code for your year Altima is either due to a weak battery or a bad AT control unit.
Weak battery
- Faulty Transmission Control Module (TCM)
- Harness is open or shorted between TCM and Engine Control Module (ECM)
- Poor circuit electrical connection between TCM and ECM

Here is the steps to check the system out yourself.


https://dl.dropboxusercontent.com/u/105565483/1d.pdf

If the transmission seems to function fine,then it is more likely to be either a weak battery or an opened or shorted communication line between the ECM and the A/T control unit?
Malfunction is detected when an incorrect signal from Transmission control module (TCM) is sent to Engine Control Module (ECM).


I would start by clearing the code and see if it returns. If it does, I would check the battery and the charging system voltage before replacing a control unit or getting crazy about checking wiring.

This will help.
Thanks.