Multiplex Integrated Control System (V6): Other Honda Accord VIII

Using the HDS (Preferred method)

Connect the HDS to the data link connector (DLC).

There are two ways to read B-CAN code with the HDS

Note. First method; On the HDS, select BODY ELECTRICAL, then select the subsystem that relates to the problem (for example: door locks, keyless, security, etc.), and then last, select the DTCs. Second method; Ground the SCS circuit with the HDS, then read the DTCs displayed in the odo/trip display in the gauge control module, then go to B-CAN SYSTEM DIAGNOSIS TEST MODE A .

How to Display DTCs on the Gauge Control Module

Enter B-CAN System Diagnosis Test Mode 1 (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE 1 AND TEST MODE 2 (WITHOUT THE HDS) ). While in Test Mode 1, when communication between the MICU and gauge control module is normal, the DTCs that have been detected and stored individually by various B-CAN (Body-controller Area Network) units will be shown one by one on the odo/trip display. To scroll through the DTCs, press the SEL/RESET button.

Scheme 9

The control unit that has stored the code can be identified by the number shown on the odometer display.

CONTROL UNIT REFERENCE CHART

How to Clear DTCs

Enter B-CAN System Diagnosis Test Mode 1 (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE 1 AND TEST MODE 2 (WITHOUT THE HDS) ). While in Test Mode 1, press and hold down the SEL/RESET button for at least 10 seconds.

Drivers MICU

DTC DESCRIPTION CHART

Passenger's MICU

DTC DESCRIPTION CHART

Door Multiplex Control Unit

DTC DESCRIPTION CHART

Gauge Control Module

DTC DESCRIPTION CHART

HandsFreeLink Control Unit

DTC DESCRIPTION CHART

Climate Control Unit

DTC DESCRIPTION CHART

Power Seat Control Unit

DTC DESCRIPTION CHART

Immobilizer-Keyless Control Unit

DTC DESCRIPTION CHART

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 (125 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 and relays the information from B-CAN to F-CAN and from F-CAN to B-CAN. This is called the Gateway Function.

Scheme 10

Gateway Function

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

Scheme 11

Network "Loss of Communication" Error Checking Function

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

Self-Diagnostic Function (On-board diagnosis)

By connecting the HDS to the data link connector (DLC), the HDS can retrieve the diagnostic information from the driver's MICU via a diagnostic line called the K-LINE. The K-LINE is a separate communication line from the CAN lines, and is connected to most of the CAN related ECUs. The driver's MICU is a gateway between the HDS and B-CAN related ECUs, and sends B-CAN diagnostic information to the HDS. When doing a function test with the HDS, the HDS sends an output signal through the K-LINE to the driver's MICU. The driver's MICU either relays the request to another ECU, or commands the function itself.

Scheme 12

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 in LOCK (0).

1. In the sleep mode, the multiplex integrated control system stops functioning (communication and CPU control) when it is not necessary for the system to operate.
2. As soon as any operation is requested (for example, a door is unlocked), the related control units in the sleep mode immediately wake up and begin to function.
3. 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.
4. The sleep mode will not function if any door or the trunk lid is open, or if a key is in the ignition switch. NOTE: Sleep and Wake-up Mode Test (see «SLEEP AND WAKE-UP MODE TEST»(ref-423728-S27002006652011092800000) ).

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.

When a CPU problem or abnormal power supply voltage is detected, the MICUs move 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 data from the B-CAN circuit cannot be received within a specified time, or if an unusual combination of data is recognized, the MICU switches to its fail-safe mode, which uses a pre-programmed value.

Power Supply Voltage Monitoring Function

The driver's MICU monitors the power supply voltage (back-up voltage). If the voltage goes below 10 V, the driver's MICU will not store a DTC.

INPUT OUTPUT REFERENCE CHART

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

The driver's MICU control of the ceiling light ON/OFF is based on input signals from each switch.

INPUT OUTPUT REFERENCE CHART

Collision Detection Signal (CDS)

The driver's MICU control of the door lock actuators is based on IG1 and SRS (CDS) inputs.

INPUT OUTPUT REFERENCE CHART

Key Interlock (A/T)

The driver's MICU control of the key interlock solenoid is based on ignition switch ACCESSORY (I) position, the transmission range switch P position, and the park-pin switch inputs.

INPUT OUTPUT REFERENCE CHART

A/C Pressure Sensor

The driver's MICU sends A/C pressure switch signal information hen the ignition switch is in the IG1 position.

INPUT OUTPUT REFERENCE CHART

Combination Light Switch

The driver's MICU control of the lighting system is based on inputs from each combination light switch.

INPUT OUTPUT REFERENCE CHART

Daytime Running Lights

The driver's MICU control of the headlights as daytime running lights is based on inputs from each switch.

INPUT OUTPUT REFERENCE CHART

Fog Lights

The driver's MICU control of fog light is based on inputs from the fog light switch.

INPUT OUTPUT REFERENCE CHART

Headlight Auto-OFF Function

The driver's MICU control of the lighting system is based on inputs from each switch.

INPUT OUTPUT REFERENCE CHART

Turn Signal/Hazard Warning Lights

The driver's MICU control of the turn signal/hazard warning lights is based on inputs from the turn signal switch and the hazard warning switch.

INPUT OUTPUT REFERENCE CHART

Courtesy Light (Driver's Side)

The driver's MICU control of the driver's and left rear door courtesy lights is based on inputs from the driver's and left rear door switches.

INPUT OUTPUT REFERENCE CHART

Wiper

The driver's MICU control of the wiper is based on inputs from each switch.

INPUT OUTPUT REFERENCE CHART

Power Window Relay

The driver's MICU control of the power windows is based on inputs from each switch.

INPUT OUTPUT REFERENCE CHART

Keyless Answer Back

The driver's MICU control of the lighting system and horns is based on keyless data sent by B-CAN.

INPUT OUTPUT REFERENCE CHART

Security Answer Back

The driver's MICU control of the lighting system and horns is based on keyless data sent by B-CAN.

INPUT OUTPUT REFERENCE CHART

Power Door Locks

The driver's MICU control of the door lock actuators is based on inputs from each switch.

INPUT OUTPUT REFERENCE CHART

Keyless Entry System

The driver's MICU control of the door lock actuators is based on inputs from each switch.

INPUT OUTPUT REFERENCE CHART

Keyless PANIC Function

The driver's MICU control of the keyless PANIC Function is based on B-CAN data.

INPUT OUTPUT REFERENCE CHART

Security Alarm System

The driver's MICU control of the lighting system and horns is based on inputs from each switch and B-CAN data.

INPUT OUTPUT REFERENCE CHART

The passenger's MICU monitors the power supply voltage (back-up voltage). If the voltage goes below 10 V, the passenger's MICU will not store DTCs.

INPUT OUTPUT REFERENCE CHART

Courtesy Light (Front Passenger's Side)

The passenger's MICU control of the front passenger door courtesy light is based on inputs from the front passenger door switch.

INPUT OUTPUT REFERENCE CHART

Power Door Locks (LOCK)

The passenger's MICU control of the front passenger's side door lock actuators is based on inputs from the driver's MICU.

INPUT OUTPUT REFERENCE CHART

Power Door Locks (UNLOCK)

The passenger's MICU control of the front passenger's side door lock actuators is based on inputs from the driver's MICU.

INPUT OUTPUT REFERENCE CHART

Exterior Lights

The passenger's MICU control of the front passenger's side headlight, and parking lights is based on inputs from the driver's MICU.

INPUT OUTPUT REFERENCE CHART

Automatic Lighting

The passenger's MICU control of the headlights and the parking lights is based on inputs from the automatic lighting sensor.

INPUT OUTPUT REFERENCE CHART

Power Window Relay Circuit

The passenger's MICU control of the power window relay circuit in the passenger's under-dash fuse/relay box is based on inputs from the power window switches.

INPUT OUTPUT REFERENCE CHART

HDS Inputs and Function Tests

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 of 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

HDS INPUTS AND FUNCTION TEST CHART

Function Test

HDS INPUTS AND FUNCTION TEST

Troubleshooting - B-CAN System Diagnosis Test Mode A

Check the ECM/PCM for DTCs and troubleshoot ECM/PCM (see GENERAL TROUBLESHOOTING INFORMATION ) or F-CAN loss of communication errors first, then do this diagnosis if the symptom is related to the B-CAN system.

Scheme 13

1. Compare the symptom with this list of B-CAN related systems: Gauge control module Exterior lights Turn signals Entry light control Interior lights Safety indicators Horns (security and panic) Chimes (key-in, seat belt, lights-on, and parking brake) Power window/moonroof timer Wiper/washer Security Keyless entry Power door locks Key interlock Dashlight brightness Immobilizer Driving position memory system (HDS name: Memory seat control unit) HandsFreeLink Is the symptom related to the B-CAN system? YES -Go to step 2. NO -Go to the system troubleshooting for the system with the symptom.
2. Connect the HDS to the data link connector (DLC) (A), then turn the ignition switch to ON (II).
3. From the BODY ELECTRICAL SYSTEM SELECT menu, select B-CAN CONTROL UNITS INFORMATION, and then select CHECK CONNECTED CONTROL UNITS listed to see if the following control units are communicating with the HDS. Driver's MICU Passenger's MICU Door multiplex control unit (HDS name: Power window unit) Gauge control module Immobilizer-keyless control unit Climate/HVAC control unit HandsFreeLink unit Power seat control unit (HDS name: Memory seat control unit) NOTE: If a unit is communicating with the HDS, DETECT will be displayed. If a unit is not communicating or the vehicle is not equipped, "NOT AVAILABLE" will be displayed. The HDS only checks the connected unit status one time when BODY ELECTRICAL is selected. To recheck the status after repair, reboot the HDS. Are all control units communicating with the HDS? YES -Go to step 4. NO -If any of the control units are not communicating, go to «B-CAN SYSTEM DIAGNOSIS TEST MODE B»(ref-423728-S28133698052011092800000) . If all units are not communicating or only the driver's MICU is communicating, go to DTC U1280 troubleshooting (see «DTC U1280: COMMUNICATION BUS LINE ERROR (BUS-OFF)»(ref-423728-S39164274182011092800000) ).
4. Select the system that has the problem from the BODY ELECTRICAL SYSTEM SELECT menu, then select DTCs. Are any DTCs indicated? YES -Go to step 5. NO -If the problem is related to one of the following items and the system that is malfunctioning does not stop or turn off, go to «B-CAN SYSTEM DIAGNOSIS TEST MODE C»(ref-423728-S39041773992011092800000) . If the problem is related to one of the following items and the system that is malfunctioning does not work or turn on, go to «B-CAN SYSTEM DIAGNOSIS TEST MODE D»(ref-423728-S18175079932011092800000) . Exterior lights Turn signals Entry lights Interior lights Horns (security and panic) Wiper/washer Power window Power door locks If the problem is related to one of the following items, go to the troubleshooting for that individual system. Gauge control module Safety indicators Chimes (key-in, seat belt, lights-on, and parking brake) Security Keyless entry Key interlock Dashlight brightness Navigation (if equipped) HandsFreeLink Immobilizer Driving position memory system Rear window defogger (climate control) Climate control
5. Record all DTCs, and sort them by DTC type.
6. Troubleshoot the DTC(s) in the order listed above. Battery voltage DTCs. Internal error DTCs. Loss of communication DTCs. Signal error DTCs.

Troubleshooting - B-CAN System Diagnosis Test Mode B

Do this diagnosis if any of the control units are not communicating (NOT AVAILABLE is displayed in the HDS) as found by the B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

1. Using the HDS, select the system that has the symptom from the BODY ELECTRICAL SYSTEM SELECT menu.
2. Select DTCs, and then check for loss of communication DTCs. Are any loss of communication DTCs indicated? YES -Go to step 3. NO -Faulty driver's MICU; replace the driver's under-dash fuse/relay box, USA models (see «DRIVER'S UNDER-DASH FUSE/RELAY BOX (MICU) REMOVAL AND INSTALLATION»(ref-423710-S13284333742011092800000) ), Canada models (see «CANADA MODELS»(ref-423710-S16150183142011092800000) ).
3. Do the power, ground, and communication part of the input test for the unit(s) not communicating with the HDS. COMMUNICATION PART REFERENCE CHART Unit not communicating Driver's MICU (see «MICU INPUT TEST»(ref-423728-S23856532222011092800000) ) Gauge control module (see «GAUGE CONTROL MODULE INPUT TEST»(ref-423701-S38901635732011092800000) ) Immobilizer-keyless control unit (see «IMMOBILIZER-KEYLESS CONTROL UNIT INPUT TEST»(ref-423699-S05873382452011092800000) ) Passenger's MICU (see «PASSENGER'S MICU»(ref-423728-S10766262602011092800000) ) Door multiplex control unit (see «POWER WINDOW MASTER SWITCH INPUT TEST»(ref-423739-S03266646642011092800000) ) Climate control unit (see «CLIMATE CONTROL POWER AND GROUND CIRCUIT TROUBLESHOOTING»(ref-423748-S09796737632011092800000) ) Audio unit (see «SYSTEM DESCRIPTION»(ref-423704-S41367272292011092800000) ) Power seat control unit (see «POWER SEAT CONTROL UNIT INPUT TEST/REPLACEMENT»(ref-423761-S01745784052011092800000) )

Troubleshooting - B-CAN System Diagnosis Test Mode C

Do this diagnosis if a component that is controlled by the B-CAN system does not stop or turn off.

Note. If the component does not turn on, go to B-CAN SYSTEM DIAGNOSIS TEST MODE D . See the B-CAN system unit input/output index for a list of input and output devices and the control units that monitor the input and control the output devices (see HDS INPUTS AND FUNCTION TESTS ).

1. Check for DTCs by selecting the MODE MENU from the HDS. Are any DTCs indicated? YES -Go to «B-CAN SYSTEM DIAGNOSIS TEST MODE A»(ref-423728-S12292851172011092800000) . NO -Go to step 2.
2. Turn off the switch that controls the malfunctioning component.
3. Select DATA LIST from the MODE MENU, and check the input of the switch that controls the component. Does the HDS indicate the switch is OFF? YES -Go to step 4. NO -Go to step 6 .
4. In the DATA LIST, check the output signal of the malfunctioning component. Is the output signal OFF? YES -Go to step 5. NO -Replace the control unit that controls the device that will not turn OFF.
5. Test the relay that does not stop or turn off. If the relay tests OK, then check for a short in the wire between the relay and the component, the relay and control unit, or the component and control unit. Are the relay and the wire harness OK? YES -Replace the control unit that controls the component that will not stop or turn OFF. NO -Replace the relay or repair/replace the wire harness.
6. Test the switch, then check for a short in the wire between the switch and the control unit that monitors the switch. Are the switch and wire harness OK? YES -Replace the control unit that monitors the switch. NO -Replace the switch or repair/replace the wire harness.

Troubleshooting - B-CAN System Diagnosis Test Mode D

Do this diagnosis if a component that is controlled by the B-CAN system does not work or come on.

Note. If the component does not turn off or stop, go to B-CAN SYSTEM DIAGNOSIS TEST MODE C . See the B-CAN system unit input/output index for a list of input and output devices and the control units that monitor the input and control the output devices (see HDS INPUTS AND FUNCTION TESTS ).

1. Check the fuse of the malfunctioning output device. Is the fuse OK? YES -Go to step 2. NO -Replace the fuse. If the fuse blows again, repair the short to ground on the fuse circuit of the malfunctioning device.
2. Check for DTCs by selecting the MODE MENU from the HDS. Are any DTCs indicated? YES -Go to «B-CAN SYSTEM DIAGNOSIS TEST MODE A»(ref-423728-S12292851172011092800000) . NO -Go to step 3.
3. Turn ON the switch that controls the malfunctioning component.
4. Select DATA LIST from the MODE MENU, and check output signal for the malfunctioning component. Is there an output signal? YES -Go to step 5. NO -Go to step 9 .
5. Test the relay and ground that controls the device that does not work, if applicable. If the relay and ground test OK, then check for an open or a short in the circuit for the malfunctioning component. Are the relay and circuit OK? YES -Go to step 6. NO -Replace the relay or repair the wire circuit.
6. Do the function test for the malfunctioning component. Does the output device pass the function test? YES -Go to step 7. NO -Replace the component.
7. With the malfunctioning output device connected, connect a voltmeter between the malfunctioning output device input and the ground wire that the control unit uses to control the output device circuit.
8. Select MISC. TEST from the MODE MENU, and do the forced operation test of the malfunctioning component. Is there a change in voltage (12 V to 0 V or 0 V to 12 V)? YES -Inspect the ground for the component. If OK, replace the component. NO -Replace the control unit that controls the malfunctioning component.
9. Select DATA LIST from the MODE MENU, and make sure the switch signal input for the malfunctioning system indicates a change when operated. Does the switch input indicate ON when the switch is ON? YES -Replace the control unit that controls the malfunctioning component. NO -Go to step 10.
10. Test the switch and its ground (if applicable), then check for an open or a short in the wire between the switch and the control unit that monitors it. Are the switch and the wire harness OK? YES -Replace the control unit that monitors the switch. NO -Replace the switch or repair/replace the wire harness.

Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2 (without the HDS)

Special Tools Required

MPCS (MCIS) Service Connector 07WAZ-001010A