ON-BOARD DIAGNOSTIC FUNCTION

• The on-board diagnostic function is incorporated into the PCM, EPS control module, ABS HU/CM, and instrument cluster. This function can narrow down CAN system malfunction locations.

• The on-board diagnostic function consists of the following functions: a failure detection function, which detects malfunctions in CAN system-related parts; a memory function, which stores detected DTCs; a self-malfunction diagnostic function, which indicates system malfunctions using DTCs and warning lights; and a PID/data monitoring function, which verifies the input/output condition of specific input/output signals being read out.

• Using a WDS or equivalent, DTCs can be read out and deleted, and the PID/data monitoring function can be activated.

• The CAN system has a fail-safe function. When a malfunction occurs in CAN system, the transmission module sends a warning signal and the receiving module illuminates the warning light.

• The failure detection function in each CAN system-related module detects malfunctions in input/output signals.

• This function outputs the DTC for the detected malfunction to the DLC-2, and also sends the detected result to the memory function and fail-safe function.

• The memory function stores the DTC for the malfunction of input/output signals for related parts, as determined by the failure detection function.

• The self-malfunction diagnostic function determines that there is a malfunction, and outputs a signal, as a DTC, to the DLC-2. The DTC can be read out using a WDS or equivalent.

DTC	Malfunction location	DTC output module
U0073	CAN system communication error	• PCM • EPS control module
U0100	Communication error to PCM	EPS control module
U0121	Communication error to ABS HU/CM	PCM
U0155	Communication error to instrument cluster	PCM
U1900	Communication error to the other module	Instrument cluster
U2012	CAN system communication error	ABS HU/CM (with ABS)
U2023	Abnormal message from PCM	EPS control module
U2516	CAN system communication error	Instrument cluster
U2522	Communication error between the PCM and ABS HU/CM (Powertrain-related signal)	ABS HU/CM (with ABS)
U2523	Communication error between the PCM and ABS HU/CM (Engine- related signal)	ABS HU/CM (with ABS)

• The PID/data monitoring function is used to freely select and read out, in real time, the monitored items for the input/output signals of the ABS HU/CM and instrument cluster.

• A WDS or equivalent is used to read out the PID/data monitor information.

PID name (definition)	WDS display	Detection state	PID monitor module	Terminal
ABS_MSG (Signal reception error from the ABS HU/CM)	Present	Circuit between the ABS HU/CM and monitor module is normal.	Instrument cluster	Instrument cluster: 2W, 2X
ABS_MSG (Signal reception error from the ABS HU/CM)	Not Present	Circuit between the ABS HU/CM and monitor module is abnormal.
PCM_MSG (Signal reception error from PCM)	Present	Circuit between the PCM and monitor module is normal.
PCM_MSG (Signal reception error from PCM)	Not Present	Circuit between the PCM and monitor module is abnormal.

• The on-board diagnostic function can narrow down a CAN system malfunction location by verifying the detected DTC and PID/data monitor information from each module. Refer to the Self-Malfunction Diagnostic Function and PID/Data Monitoring Function for detailed information regarding DTCs and the PID/data monitor. (See Self-Malfunction Diagnostic Function.) (See PID/Data Monitoring Function.)

1. DTCs for the PCM, ABS HU/CM and instrument cluster can be verified using a WDS or equivalent.

Module	Displayed DTC	Probable malfunction location
PCM	U0073	PCM-related CAN system malfunction
	U0121	Communication error between PCM and ABS HU/CM
	U0155	Communication error between PCM and instrument cluster
ABS HU/CM	U2523	Communication error between PCM and ABS HU/CM
Instrument cluster	U1900	Instrument cluster-related CAN system malfunction

2. PID/data monitor information for the instrument cluster can be verified using a WDS or equivalent.

Module	PID name (definition)	Condition	Probable malfunction point
Instrument cluster	PCM_MSG (Missing message from the PCM)	Not Present	Communication error between instrument cluster and PCM
Instrument cluster	ABS_MSG (Missing message from the ABS HU/CM)	Present	Normal communication between instrument cluster and ABS HU/CM

3. If there is a communication error between the ABS HU/CM and PCM, or between the instrument cluster and PCM, even if the communication between the ABS HU/CM and the instrument cluster is normal, it is probable that there is a malfunction in the PCM or PCM-related wiring harnesses.