Acura TSX / Honda Accord CL. Manual — part 146

YES: Replace the control unit that monitors the switch.

NO: Replace the switch or repair the wire harness.

B-CAN SYSTEM DIAGNOSIS TEST MODE D

1. Check the fuse of the malfunctioning output device.

Is the fuse OK?

YES: Go to step 2.

NO: Replace the fuse and recheck.

2. Check for DTCs by selecting the TEST MODE MENU from the Honda Diagnostic System (HDS).

Are any DTCs indicated?

YES: Go to B-CAN System Diagnosis Test Mode A.

NO: Go to step 3.

3. Turn ON the switch that controls the malfunctioning component.

4. Select DATA LIST from the TEST 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. Check the relay and ground, 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. Perform 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 component, connect a voltmeter between the malfunctioning component

and body ground on the wire that the control unit uses to control the component circuit.

NOTE:

z

Perform this diagnosis a component that is controlled by the B-CAN
system does not run or does not come on.

z

If the component does not turn off or does not stop, go to B-CAN System
Diagnosis Test Mode C.

z

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 B-CAN SYSTEM SWITCH DEVICE INDEX ).

z

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

2004 Acura TSX

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX

8. Select MISC. TEST from the TEST 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 indicate 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.

Is 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.

B-CAN SYSTEM DIAGNOSIS TEST MODE 1 (TROUBLESHOOTING WITHOUT THE HDS)

1. Check the No. 7 (10A) fuse and No. 21 (7.5A) fuse in the under-dash fuse/relay box.

Are the fuses OK?

YES: Go to step 2.

NO: Find and repair the cause of the blown fuse.

2. Remove the left kick panel (see TRIM REMOVAL/INSTALLATION - DOOR AREA ).

3. Turn the ignition switch ON (II).

4. Connect the MPCS Service connector (A) to the MCIC socket (B) in the under-dash fuse/relay box.

2004 Acura TSX

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX

Fig. 15: Connecting The MPCS Service Connector To The MCIC Socket In The Under-Dash
Fuse/Relay Box

5. Wait 5 seconds, then watch the ceiling light.

6. If there is a DTC, the ceiling light and ignition switch light will blink, pause, then repeat the DTC as long

2004 Acura TSX

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX

as the ignition switch ON (II).

Is there a repeating DTC?

YES: Count the blinks, then go to step 7.

NO: Go to step 8 .

7. About 1 second after you go into self-diagnosis Mode 1, the ceiling light will indicate the DTC, and

repeat it every 3 seconds. If there is more than one DTC, the system will indicate them in ascending
order, beginning from the DTC with the lowest numerical value. Troubleshoot the DTCs as indicated
below:

z

DTC 2, 3, 4 And 5 Simultaneously: Check for an open in the BLU wire between multiplex
integrated control unit D11 and relay module J7, BRN/RED wire between multiplex integrated
control unit J4 and door multiplex control unit No. 16, LT GRN wire between multiplex integrated
control unit X27 and combination switch control unit No. 4, BRN/YEL wire between multiplex
integrated control unit N28 and gauge B25. If the wire is OK, substitute a known-good under-dash
fuse/relay box (multiplex integrated control unit), under-hood fuse/relay box, power window
master switch, wiper/washer switch and gauge one at a time, in that order, and recheck for the
DTCs after each substitution.

z

DTC 1 Only: Go to MICU input test (see MULTIPLEX INTEGRATED CONTROL UNIT
INPUT TEST ).

z

DTC 2 Only (No Other DTCs Present): Go to the relay module input test. If all inputs are OK,
substitute a known-good relay module and then a MICU, one at a time, and then check for DTCs. If
a DTC recurs after a substitution, replace that unit.

z

DTC 3 Only (No Other DTCs Present): Go to the door multiplex control unit input test. If all
inputs are OK, substitute a known-good door multiplex control unit and then a MICU, one at a
time, and then check for DTCs. If a DTC recurs after a substitution, replace that unit.

z

DTC 4 Only (No Other DTCs Present): Go to the combination switch control unit input test. If
all inputs are OK, substitute a known-good wiper/washer switch and then a MICU, one at a time,
and then check for DTCs. If a DTC recurs after a substitution, replace that unit.

z

DTC 5 Only (No Other DTCs Present): Go to the gauge control module input test. If all inputs
are OK, substitute a known-good gauge control module and then a MICU, one at a time, and then
check for DTCs. If a DTC recurs after a substitution, replace that unit.

2004 Acura TSX

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX