Honda CR-V: System Description

MICU Control Functions Index

The MICU (built into the under-dash fuse/relay box) is one of the B-CAN components. The MICU controls many systems related to the body controller area network, and also works as a gateway to diagnose the other B-CAN circuits with the HDS.

Refer to each system circuit diagram for details.

Honda CR-V. Multiplex Integrated Control System

The MICU also controls the function of these circuits:

Body Controller Area Network (B-CAN) and Fast Controller Area Network (F-CAN)

The body controller area network (B-CAN) and the fast controller area network (F-CAN) share information between multiple electronic control units (ECUs). B-CAN communication moves at a slower speed (33.33 kbps) for convenience related items and for other functions. F-CAN information moves at a faster speed (500 kbps) for "real time" functions such as fuel and emissions data. To allow both systems to share information, the gauge control module translates information from B-CAN to F-CAN and from F-CAN to B-CAN.

Honda CR-V. Multiplex Integrated Control System

Gateway Function

The gauge control module acts as a gateway to allow both systems to share information, the gauge control module translates information from B-CAN to F-CAN and from F-CAN to B-CAN.

Honda CR-V. Multiplex Integrated Control System

Network "Loss of Communication" Error Checking Function

The ECUs on the CAN circuit send messages to each other, If there are any malfunctions on the network, the odo/trip display on the gauge control module can indicate the error messages by entering the gauge self-diagnostic function.

Error Code List

Honda CR-V. Multiplex Integrated Control System

NOTE: For further information about Error indication, refer to the gauge control module self-diagnostic function.

Example: Error 1

Honda CR-V. Multiplex Integrated Control System

Self-diagnostic Function

By connecting the HDS to the data link connector (DLC), the HDS can retrieve the diagnostic results from the MICU via a diagnostic line called KLINE. The KLINE is distinguished from the CAN line, and connected to the CAN related ECUs.

The MICU is a gateway between the HDS and B-CAN related ECUs, and sends B-CAN diagnostic results to the HDS.

When performing a function test with the HDS, the HDS sends an output signal through the KLINE to the MICU. The MICU either relays the request to another ECU, or commands the function its self.

Honda CR-V. Multiplex Integrated Control System

Wake-up and Sleep Function

The multiplex integrated control system has "wake-up" and "sleep" functions to decrease parasitic draw on the battery when the ignition switch is OFF.

NOTE: Sleep and Wake-up Mode Test.

Fail-safe Function

To prevent improper operation, the MICU has a fail-safe function. In the fail-safe mode, the output signal is fixed when any part of the system malfunctions (for example, a faulty control unit or communication line).

Each control unit has a hardware fail-safe function that fixes the output signal when there is a CPU malfunction, and a software fail-safe function that ignores the signal from a malfunctioning control unit, which allows the system to operate normally.

Hardware Fail-safe Control

Fail-safe function

When a CPU problem or a abnormal power supply voltage is detected, the MICU moves to the hardware fail-safe mode, and each system output load is set to the pre-programmed fail-safe value.

Software Fail-safe Control

When any of the data from the B-CAN circuit cannot be received within a specified time, or an unusual combination of the data is recognized, the MICU moves to the software fail-safe mode. The data that cannot be received is forced to a pre-programmed value.

Power Supply Voltage Monitoring Function

The MICU monitors the power supply voltage (back-up voltage). If the voltage goes below 10 V, the MICU sends a MICU message and will not store DTCs.

Honda CR-V. Multiplex Integrated Control System

Entry Lights Control System (Ceiling Lights, Map Lights, Ignition Key Light)

The MICU controls the ceiling light ON/OFF based upon the input signals from each switch.

Honda CR-V. Multiplex Integrated Control System

Cargo Area Lights Control

The MICU controls the cargo area light ON/OFF based upon the input signals from each switch.

Honda CR-V. Multiplex Integrated Control System

Collision Detection Signal (CDS)

The MICU controls the door lock actuators based upon the IG1 and the SRS signals.

Honda CR-V. Multiplex Integrated Control System

Key Interlock

The MICU controls the key interlock solenoid based upon the ignition switch (ACC), the transmission range switch, and the park-pin switch signals.

Honda CR-V. Multiplex Integrated Control System

Key-in Reminder

The MICU controls the door lock actuators based upon the ignition key switch, the driver's door switch, and the driver's door lock knob switch signals.

Honda CR-V. Multiplex Integrated Control System

Power Window Timer Operation

The MICU controls the power window key-off timer based upon the ignition key switch, driver's and front passenger's door switch signals.

Honda CR-V. Multiplex Integrated Control System

Headlight

The MICU controls the headlight based upon the input signals from each switch.

Honda CR-V. Multiplex Integrated Control System

Daytime Running Lights

The MICU controls the exterior lights as daytime running lights based upon the input signals from each switch.

Honda CR-V. Multiplex Integrated Control System

Turn Signal/Hazard Flasher

The MICU controls the turn signal/hazard flasher lights based upon the input signals from the turn signal switch and the hazard warning switch.

Honda CR-V. Multiplex Integrated Control System

Turn Signal One Touch Operation

The MICU controls the turn signal switch based upon the input signals from the turn signal switch.

Honda CR-V. Multiplex Integrated Control System

Windshield Wiper

The MICU controls the windshield wiper based upon the input signals from each switch.

Honda CR-V. Multiplex Integrated Control System

Windshield Wiper (Vehicle Speed Sense)

The MICU controls the windshield wiper based upon the input signals from each switch.

Honda CR-V. Multiplex Integrated Control System

Rear Window Wiper

The MICU controls the rear window wiper based upon the input signals from each switch.

Honda CR-V. Multiplex Integrated Control System

Windshield/Rear Window Washer

The MICU controls the washer operation based upon the input signals from washer switches.

Honda CR-V. Multiplex Integrated Control System

Answer Back Response Operation (Part 1)

The MICU controls the lighting system and horn based upon the B-CAN signals.

Honda CR-V. Multiplex Integrated Control System

Answer Back Response Operation (Part 2)

The MICU controls the lighting system and horn based upon the B-CAN signals.

Honda CR-V. Multiplex Integrated Control System

Power Door Locks (1 motion all doors and tailgate unlock)

The MICU controls the door lock actuators based upon the input signals of each. switch.

Honda CR-V. Multiplex Integrated Control System

Power Door Locks (2 motions all doors and tailgate unlock)

The MICU controls the door lock actuators based upon the input signals of each switch.

Honda CR-V. Multiplex Integrated Control System

Door Lock Response Operation

The MICU controls the door lock actuators based upon the B-CAN signals.

Honda CR-V. Multiplex Integrated Control System

Keyless Entry System (1 motion all doors and tailgate unlock)

The MICU controls the door lock actuators based upon the input signals of each switch and the B-CAN signals.

Honda CR-V. Multiplex Integrated Control System

Keyless Entry System (2 motions all doors and tailgate unlock)

The MICU controls the door lock actuators based upon the input signals of each switch and the B-CAN signals.

Honda CR-V. Multiplex Integrated Control System

Keyless PANIC Operation

The MICU controls the keyless PANIC operation based upon the B-CAN signals.

Honda CR-V. Multiplex Integrated Control System

Power Door Locks (Lock operation)

The MICU controls the door lock actuators based upon the input signals of each switch.

Honda CR-V. Multiplex Integrated Control System

Power Door Locks (UNLOCK operation)

The MICU controls the door lock actuators based upon the input signals of each switch.

Honda CR-V. Multiplex Integrated Control System

Security Alarm System

The MICU controls the lighting system and horns based upon the input signals of each switch and the B-CAN signals.

Honda CR-V. Multiplex Integrated Control System

Tailgate Outer Handle Operation (1 motion all doors and tailgate unlock)

The MICU controls the tailgate release actuator based upon the tailgate outer handle switch and the driver's door lock knob switch signals.

Honda CR-V. Multiplex Integrated Control System

Tailgate Outer Handle Switch Operation (2 motions all doors and tailgate unlock)

The MICU controls the tailgate release actuator based upon the tailgate outer handle switch and the door lock knob switch signals.

Honda CR-V. Multiplex Integrated Control System

HDS Inputs and Commands

Certain inputs happen so quickly that the HDS cannot update fast enough. Hold the switch that is being tested while monitoring the Data List.

This should give the HDS time to update the signal on the Data List.

Because the HDS software is updated to support the release for newer vehicles it is not uncommon to see system function tests that are not supported.

Make sure that the most current software is loaded.

Input:

Honda CR-V. Multiplex Integrated Control System

Honda CR-V. Multiplex Integrated Control System

Honda CR-V. Multiplex Integrated Control System

Honda CR-V. Multiplex Integrated Control System

Function Test:

Honda CR-V. Multiplex Integrated Control System

READ NEXT:

 Troubleshooting

Troubleshooting - B-CAN System Diagnosis Test Mode A Check the PCM for DTCs, and troubleshoot PCM or F-CAN loss of communication errors first, then do this diagnosis if the symptom is related to the B

 Sleep and Wake-up Mode Test

1. Shift to the sleep mode: Turn the ignition switch OFF, and remove the key. If the MICU receives no signals from the inputs listed below, it will go into sleep mode in less than 40 seconds. Drive

 DTC Troubleshooting

DTC B1000: Communication Bus Line Error (Bus-off) 1. Clear the DTCs with the HDS. 2. Turn the ignition switch OFF, and then back ON (II). 3. Wait for 6 seconds or more. 4. Check for DTCs with the H

SEE MORE:

 System Description

Outline The rear differential has a real-time 4WD control mechanism that enables 4WD by transmitting appropriate driving force from the front wheels to the rear wheels when necessary. It uses a real-time 4WD dual pump system (DPS) with a light and compact cam mechanism, and integrates the drive co

 How Your Side Curtain Airbags Work

In a Side Impact In a moderate to severe side impact, sensors will detect rapid acceleration and signal the control unit to instantly inflate the side curtain airbag. If the impact is on the passenger’s side, the passenger’s side curtain airbag will inflate even if there are no

© 2016-2021 Copyright www.hcrv.net