Acura CSX. Manual — part 508

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Self-diagnostic Function

22-83

GAUGE CONTROL MODULE

CAN H

CAN L

B-CAN

B-CAN (33.33 kbps)

F-CAN (500 kbps)

SRS UNIT

MICU

ECM/PCM

ABS MODULATOR-
CONTROL UNIT*

IMMOBILIZER-
KEYLESS
CONTROL UNIT

K-LINE

DATA LINK
CONNECTOR

HDS

CLIMATE CONTROL
UNIT

TMPS CONTROL
UNIT*

EPS CONTROL
UNIT

NAVIGATION
UNIT

VSA MODULATOR-
CONTROL UNIT*

HANDSFREELINK
CONTROL UNIT*

AUDIO UNIT

YAWRATE-LATERAL
ACCELERATION
SENSOR*

*1: ’06-08 Touring and Premium models
*2: ’07 TYPES and ’08-09 models
*3: ’08-09 models
*4: ’09 model with navigation system

1

3

2

4

2

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 K-LINE. The K-LINE 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 doing a function test with the HDS, the HDS sends an output signal through the K-LINE to the MICU. The MICU
either relays the request to another ECU, or commands the function its self.

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Wake-up and Sleep Function

Fail-safe Function

Hardware Fail-safe Control

Software Fail-safe Control

Fail-safe function

22-84

Multiplex Integrated Control System

The multiplex integrated control system has wake-up and sleep functions to decrease parasitic draw on the battery
when the ignition switch in LOCK (0).

• In the sleep mode, the MICU stops functioning (communication and CPU control) when it is not necessary for the

system to operate.

• As soon as any operation is requested (for example, a door is unlocked), the related control unit in the sleep mode

immediately wakes up and begins to function.

• When the ignition switch is turned to LOCK (0), and the driver’s door is opened, then closed, there is a delay of about

40 seconds before the control unit goes from the wake-up mode to the sleep mode.

• The sleep mode will not function if any door is opened or if a key is in the ignition.
• The draw is reduced from 200 mA to less than 35 mA when in the sleep mode.

NOTE: Sleep and Wake-up Mode Test (see page 22-99).

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.

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.

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.

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Power Supply Voltage Monitoring Function

Entry Lights Control System

Lighting System (Headlights, Parking Lights, Fog Lights, Side Marker Lights, License Plate

Lights, and Taillights)

Daytime Running Lights

Turn Signal/Hazard Warning Lights

Door Lock Response Operation

Power Window Key-off Operation

Input

Output

Input

Output

Input

Output

Input

Output

Input

Output

Input

Output

Input

Output

22-85

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.

MICU

Battery voltage

MICU

: MICU internal circuit

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

MICU

IG1 power supply
Ignition key switch
Driver’s door switch
Front passenger’s door switch
Left rear door switch
Right rear door switch
Driver’s door lock knob switch (LOCK)

Interior light

B-CAN

Keyless LOCK signal

The MICU contains the relay circuits for the headlight high/low beams and taillights, and controls the lighting system ON/OFF based upon input
signals from the combination light switch.

MICU

Headlight OFF switch
Headlight ON switch
Fog light switch
Dimmer switch
Combination light switch (parking lights, side marker lights,
license plate lights, and taillights)
Passing switch

Headlights (low beam)
Headlights (high beam)
Parking lights
Fog lights
Side marker lights
License plate lights
Taillights

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

MICU

Headlight OFF switch
Headlight ON switch
Dimmer switch
Combination light switch (parking lights, side marker lights,
license plate lights, and taillights)
Passing switch

Headlights (low beam)
Headlights (high beam)
Parking lights
Slide marker lights
License plate lights
Taillights

B-CAN

Transmission range switch (P position)

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

MICU

IG1 power supply
Turn signal switch (left/right)
Hazard warning switch

Turn signal lights (left/right)

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

B-CAN

Door lock signals

Door lock actuator (LOCK/UNLOCK)
Driver’s door lock actuator (UNLOCK)
Trunk lid release actuator

The MICU controls the power windows key-off operation based upon input signals from each switch.

MICU

IG1 power supply
Ignition key switch
Driver’s door switch
Front passenger’s door switch

Power window key-off timer

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Power Door Locks (Vehicle Speed Sense)

Power Door Locks (Normally LOCK/UNLOCK Operation)

Keyless Entry System

Keyless PANIC

Input

Output

Input

Output

Input

Output

Input

Output

22-86

Multiplex Integrated Control System

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

MICU

IG1 power supply
Driver’s door switch
Front passenger’s door switch
Left rear door switch
Right rear door switch
Trunk lid latch switch
Driver’s door lock knob switch (UNLOCK)
Front passenger’s door lock knob switch (UNLOCK)
Left rear door lock knob switch (UNLOCK)
Right rear door lock knob switch (UNLOCK)
Transmission range switch (P position)

Door lock (LOCK)

B-CAN

Vehicle speed pulse
Engine RPM

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

MICU

IG1 power supply
Ignition key switch
Driver’s door switch
Front passenger’s door switch
Left rear door switch
Right rear door switch
Trunk lid latch switch
Driver’s door lock knob switch (LOCK)
Driver’s door lock switch (LOCK/UNLOCK)
Driver’s door key cylinder switch (UNLOCK)
Front passenger’s door lock switch (LOCK/UNLOCK)

Door lock actuators (LOCK/UNLOCK)

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

MICU

IG1 power supply
Ignition key switch
Driver’s door switch
Front passenger’s door switch
Left rear door switch
Right rear door switch
Trunk lid latch switch
Driver’s door lock knob switch (LOCK/UNLOCK)
Driver’s door lock switch (LOCK/UNLOCK)
Driver’s door key cylinder switch (UNLOCK)
Front passenger’s door lock switch (LOCK/UNLOCK)
Transmission range switch (P position)

Door lock actuator (LOCK/UNLOCK)
Driver’s door lock actuator (UNLOCK)
Trunk lid release actuator

B-CAN

Keyless LOCK signal

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

B-CAN

Keyless PANIC signal (action, headlight low, parking light
and horn)

Headlights (low beam)
Parking lights
Side marker lights
License plate lights
Taillights
Horn

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