Nissan Sentra B18 (2020-2025) Service Manual: U0101 Can Comm Circuit

Dtc Description

DTC Description

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-Nissan Sentra vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a Nissan Sentra vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected 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 DETECTION LOGIC

DTC	CONSULT screen terms (Trouble diagnosis content)	DTC detection condition
U0101	LOST COMM (TCM) (Lost Communication with TCM)	Diagnosis condition	Ignition switch ON
		Signal (terminal)	CAN communication signal
		Threshold	ECM is not transmitting or receiving CAN communication signal of OBD (emission-related diagnosis) with TCM
		Diagnosis delay time	2 seconds or more

POSSIBLE CAUSE

Harness or connectors (CAN communication line is open or shorted)

FAIL-SAFE

Engine Control System

Engine operating condition in fail-safe mode
Fail safe mode		Nissan Sentra Vehicle behavior
Others		ECM operates active grille shutter to fully-open position.

Idle Start/Stop System

Not applicable

Confirmation Procedure

Confirmation Procedure

1. PERFORM DTC CONFIRMATION PROCEDURE

   1. Turn ignition switch ON and wait at least 3 seconds.

   2. Check DTC.

   Is DTC detected?

   YES >>

   Refer to DTC Diagnosis Procedure.

   NO-1 >>

   To check malfunction symptom before repair: Refer to Intermittent Incident.

   NO-2 >>

   Confirmation after repair: INSPECTION END

Dtc Diagnosis Procedure

DTC Diagnosis Procedure

Perform the trouble diagnosis for CAN communication system. Refer to Trouble Diagnosis Flow Chart.