Acura TSX / Honda Accord CL. Manual - part 54

Fig. 36: Control Unit Input Test (Disconnected) 

10. Perform the Gauge Self-diagnosis Procedure (see SELF-DIAGNOSTIC PROCEDURE ). 

z

If the beeper sounds and the seat belt reminder light flashes, go to step 11.  

z

If the beeper does not sound or the seat belt reminder light does not flash, replace the gauge control 
module.  

11. Substitute a known-good under-dash fuse/relay box and recheck the system. 

z

If the symptom is gone, the multiplex integrated control unit (MICU) is faulty; replace the under-
dash fuse/relay box.  

z

If the symptom is still present, the gauge control module is faulty; replace the gauge control 
module.  

 

2004 Acura TSX 

2004 ACCESSORIES & EQUIPMENT Gauges & Indicators - TSX

  

 

2004 ACCESSORIES & EQUIPMENT

Multiplex Integrated Control System - TSX 

COMPONENT LOCATION INDEX 

Fig. 1: Locating Multiplex Integrated Control System Components (1 Of 2)

 

2004 Acura TSX 

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX

  

 

2004 Acura TSX 

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX

  

 

 

Fig. 2: Locating Multiplex Integrated Control System Components (2 Of 2) 

SYSTEM DESCRIPTIONS 

BODY CONTROLLER AREA NETWORK (B-CAN) & FAST CONTROLLER AREA NETWORK (F-
CAN): 

Fast Controller Area Network (F-CAN) and Body Controller Area Network (B-CAN) share information 
between multiple Electronic Control Units (ECUs). B-CAN communication moves at a slower speed for 
convenience related items, and for other functions. F-Can information moves at a faster speed 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. 

The ECUs on the B-CAN and F-CAN transmit and receive information in the form of structured messages that 
may be received by several different ECUs on the network at one time. These message are transmitted and 
received across a communication circuit that consists of a single wire that is shared by all the ECUs on the 
circuit. Since messages on the F-CAN network are typically of higher importance, a second wire is used for 
communication circuit integrity monitoring. A backup circuit is also added to the headlight and wiper circuits 

 

2004 Acura TSX 

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX

  

 

on the B-CAN network in the event of a network wire or ECU failure that would effect the operation of the 
system. 

Fig. 3: Network Schematic 

Messages are transmitted by an ECU (that monitors an input) over the communication circuit. ECUs that use 
the message (information related to that input) are the receivers. For example, the Combination Switch Control 
Unit monitors the wiper switch. When the wiper switch is placed in the low speed position, the Combination 
Switch Control Unit transmits that message on the communication circuit. The Relay Control Module receives 
the message and turns on the wipers by providing a ground for the relay.

 

2004 Acura TSX 

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX