Multiplex Integrated Control System: Other Honda Fit GE

Using the HDS (Preferred method)

Connect the HDS to the Data Link Connector (DLC).

Note. There are two methods to read B-CAN codes with the HDS.

First method: Go to B-CAN System Diagnosis Test Mode A to check for DTCs (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Second method: Ground the SCS circuit with the HDS, then read the DTCs displayed in the gauge control module, then go to B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

How to Display DTCs On the Gauge Control Module

Set the 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, the DTCs which have been detected and stored individually by various B-CAN (Body-controller Area Network) units, will be shown one by one on the LCD display when the communication between the MICU and the gauge control module is normal. To scroll through the DTCs, press the select/reset button.

Scheme 4

The unit that has stored the code can be identified by the number shown on the odo/trip display.

ODO/TRIP DISPLAY REFERENCE TABLE

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.This is called the Gateway Function.

Scheme 5

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.

Scheme 6

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 LCD 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

By connecting the HDS to the data link connector (DLC), the HDS can retrieve the diagnostic information from the MICU via a diagnostic line called K-LINE. The K-LINE is separate from the CAN lines, and is connected to the CAN related ECUs. The MICU is a gateway between the HDS and B-CAN related ECUs, and it 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 MICU. The MICU either relays the request to another ECU or commands the function itself.

Scheme 7

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 turned to 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 is opened or if a key is in the ignition.
5. The draw is reduced from 200 mA to less than 35 mA when in the sleep mode.

Note. See 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 an 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 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.

POWER SUPPLY VOLTAGE MONITORING FUNCTION TABLE

Combination Light Switch

The MICU controls the lighting system based on input from the combination light switch.

LIGHTING SYSTEM REFERENCE TABLE

Fog Lights

The MICU control of the fog lights is based on input signal from the fog light switch.

FOG LIGHTS REFERENCE TABLE

Turn Signal/Hazard Warning Lights

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

TURN SIGNAL/HAZARD WARNING LIGHTS REFERENCE TABLE

Entry Light Control System

The MICU control of the interior lights is based on input signals of each switches and the keyless signals sent by the B-CAN.

ENTRY LIGHT CONTROL SYSTEM REFERENCE TABLE

Cargo Area Light

The MICU control of the cargo area light is based on the tailgate latch switch.

CARGO AREA LIGHT REFERENCE TABLE

Daytime Running Lights

The MICU controls the headlights as daytime running lights based on input from each switch and B-CAN signals.

LIGHTING SYSTEM REFERENCE TABLE

Windshield Wiper/Washer

The MICU controls the windshield wiper motor and windshield washer motor based on input signals from each switch and B-CAN signals.

WINDSHIELD WIPER/WASHER REFERENCE TABLE

Rear Window Wiper

The MICU control of the rear window wiper motor and washer motor is based on input signals from each switch.

REAR WINDOW WIPER REFERENCE TABLE

Windshield/Rear Window Washer

The MICU controls the windsheild washer and the rear window washer motor based on inputs from each switch.

WASHER REFERENCE TABLE

Key Interlock (A/T)

The MICU control of the key interlock solenoid is based on input signals from each switch.

KEY INTERLOCK (A/T) REFERENCE TABLE

Collision Detection Signal (CDS)

The MICU controls the door lock actuators based on the IG1 and SRS (CDS) inputs.

COLLISION DETECTION SIGNAL REFERENCE TABLE

Power Door Locks

The MICU control of the door lock actuators is based on input signals from each switch.

POWER DOOR LOCKS REFERENCE TABLE

Keyless Entry System

The MICU controls the door lock actuators based on inputs of each switch.

KEYLESS ENTRY SYSTEM REFERENCE TABLE

Keyless Panic Function

The MICU control of the keyless PANIC operation is based on the B-CAN signal.

KEYLESS PANIC FUNCTION REFERENCE TABLE

Security Alarm System

The MICU controls the exterior lights and the horn based on inputs of each switch.

SECURITY ALARM SYSTEM REFERENCE TABLE

HDS Inputs, Outputs and Commands

Certain inputs happen so quickly that the Data List on 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.

DATA LIST REFERENCE TABLE

DATA LIST REFERENCE TABLE

Function Test

FUNCTION TEST REFERENCE TABLE

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.

Note. Always cycle the ignition switch within 3 seconds when prompted in the DTC troubleshooting procedures in this section.

Scheme 8

1. Compare the symptom with this list of B-CAN related systems: Gauge control module Gauge control module Exterior lights Entry light control Horns (security and panic) Wiper/washer Security Keyless entry Power door locks Immobilizer 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 (A), then turn the ignition switch to ON (II).
3. From the BODY ELECTRICAL menu, select B-CAN CONTROL UNITS INFORMATION, and then select CONNECTED UNIT listed to see if the following control units are communicating with the HDS. MICU Gauge control module Immobilizer-keyless control unit HandsFreeLink 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 units status one time when BODY ELECTRICAL is selected. To recheck the status after repair, reboot the HDS and repeat step 3 . 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 (see «TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE B»(ref-320472-S39316195992009071400000) ). If all units are not communicating or only the MICU is communicating, go to DTC B1000 troubleshooting (see «DTC TROUBLESHOOTING»(ref-320472-S13696584312009071400000) ).
4. Select the system that has the problem from the BODY ELECTRICAL menu, then select DTCs. Are any DTCs indicated? YES - Go to step 6 . NO - If the problem is related to one of the following items, go to B-CAN System Diagnosis Test Mode C (see «TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE C»(ref-320472-S23890847732009071400000) ) if the system does not stop or turn off. Go to Test Mode D (see «TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE D»(ref-320472-S03947963332009071400000) ) if the system does not run or turn on. Exterior lights Entry light control Horns (security and panic) Wiper/washer If the problem is related to one of the following items, go to the troubleshooting for that individual system. Gauge control module Security Keyless entry HandsFreeLink
5. Record all DTCs, and sort them by DTC type.
6. Troubleshoot the DTC(s) in the order listed below: 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 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 - Replace the MICU (see appropriate «REMOVAL AND INSTALLATION»(ref-320466-S37197492852009071400000) procedure ).
3. Do the power, ground, and communication part of the input test for the unit not communicating with the HDS. UNIT NOT COMMUNICATING REFERENCE TABLE Unit not communicating MICU (see «MICU INPUT TEST»(ref-320472-S29635551532009071400000) ) Gauge control module (see «GAUGE CONTROL MODULE INPUT TEST»(ref-320449-S28307298332009071400000) ) Immobilizer-keyless control unit (see «IMMOBILIZER-KEYLESS CONTROL UNIT INPUT TEST»(ref-320464-S27722014662009071400000) ) HandsFreeLink control unit

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 TROUBLESHOOTING - 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 controls the output devices {see HDS INPUTS, OUTPUTS, AND COMMANDS ). Always cycle the ignition switch within 3 seconds when prompted in the DTC troubleshooting procedures in this section.

1. Check for DTCs by selecting the TEST MODE menu from the HDS. Are any DTCs indicated? YES - Go to B-CAN System Diagnosis Test Mode A (see «TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A»(ref-320472-S29441961612009071400000) ). NO - Go to step 2 .
2. Turn off the switch that controls the malfunctioning component.
3. Select the applicable system from the system MODE MENU, then select DATA LIST, 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. k the relay that does not stop or turn off, if applicable, 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 turn OFF. NO - Replace the relay or repair the wire harness.
6. Check 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 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 run or come on.

Note. If the component does not turn off or stop, go to B-CAN System Diagnosis Test Mode C (see TROUBLESHOOTING - 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 controls the output devices (see HDS INPUTS, OUTPUTS, AND COMMANDS ).

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 a short to ground on the fuse circuit of the malfunctioning device.
2. Check for DTCs by selecting the TEST MODE menu from the HDS. Are any DTCs indicated? YES - Go to B-CAN System Diagnosis Test Mode A (see «TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A»(ref-320472-S29441961612009071400000) ). NO - Go to step 3 .
3. Turn ON the switch that controls the malfunctioning component.
4. Select the applicable system from the system MODE MENU, then select DATA LIST, 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 control 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 FUNCUTIONAL 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 - Replace the component. NO - Replace the control unit that controls the malfunctioning component.
9. Select DATA LIST from the TEST MODE menu, and make sure the switch signal input for the malfunctioning system indicates a change when operated. Does the switch input indicated ON when the switch is ON? YES - Replace the control unit that controls the malfunctioning component. NO - Go to step 10 .
10. Check 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 the wire harness.