The ECM communicates with the following ECM and ECUs using the signals listed below. The following table explains receiving and sending signals by ECM or ECU.

COMMUNICATION LINE CHART

Transmit To	Receive From	Signal	Communication Line
HV ECU	ECM	Inspection mode signal MIL illumination requirement Shift position information Ready state Starter ON	CAN
ECM	HV ECU	Ambient temperature Intake air temperature Radiator fan drive Engine warm-up requirement Engine rpm	CAN
ECM	Battery ECU	Engine rpm	CAN
ECM	Power Steering ECU	Inspection mode	CAN
ECM	Skid Control ECU	Inspection mode	CAN
ECM	Body ECU	Inspection mode Engine rpm	BEAN, CAN
Combination Meter ECU	ECM	Fuel level	BEAN, CAN
ECM	Combination Meter ECM	Engine coolant temperature Engine rpm Injection volume Inspection mode Engine oil pressure switch	BEAN, CAN
ECM	Air Conditioner Amplifier ECU	Engine coolant temperature Engine rpm Ambient temperature Coolant heat storage water valve close	BEAN, CAN
ECM	Certification ECU	Engine rpm	BEAN, CAN
ECM	EMV	Engine coolant temperature Inspection mode Engine oil pressure switch	ACV LAN, CAN

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

System Diagram: Communications

Use the Manual With the Right Hardware

When to See a Mechanic