DTC Description

CAN (Controller Area Network) is a serial communication line for real time applications. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Modern vehicle is equipped with many electronic control unit, 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 No.	M.U.T.-III SE screen items (Trouble diagnosis content)		DTC detection condition
U2140-87	CAN comm err (ECM) [Controller area network communication error (Engine control module)]	[MISSING MESSAGE]	Diagnosis condition	When ignition switch is ON
			Signal (terminal)	CAN communication signal
			Threshold	When IPDM E/R cannot communicate CAN communication signal
			Diagnosis delay time	2 seconds or more

POSSIBLE CAUSE

CAN communication system

FAIL-SAFE

When CAN communication with ECM is impossible, IPDM E/R performs fail-safe control. After CAN communication recovers normally, it also returns to normal control.

If No CAN Communication Is Available With ECM

Control part	Fail-safe operation
Cooling fan	The cooling fan is operated at HI operation when the ignition switch is turned ON. Turn OFF the cooling fan operation when the ignition switch is turned OFF.
A/C compressor	A/C compressor OFF

DTC CONFIRMATION PROCEDURE

1.PERFORM DTC CONFIRMATION PROCEDURE

With M.U.T.-III SE

Ignition switch ON and wait for 2 seconds or more.
Check “Self Diagnostic Result” of “IPDM E/R” using M.U.T.-III SE.

Is DTC detected?

Refer to Diagnosis Procedure

-1 To check malfunction symptom before repair: Refer to Intermittent IncidentIntermittent Incident

-2 Confirmation after repair: INSPECTION END