Acura TSX / Honda Accord CL. Manual - part 65

Is DTC B1178, B1168 and/or B1169 indicated? 

YES: Go to step 5.  

NO: Intermittent failure, the F-CAN communication line is OK at this time. Check for loose 
or poor connections. If the connections are good, check the battery condition and the 
charging system. See GENERATORS & REGULATORS .  

5. Check for DTCs in the ECM/PCM. 

Are any DTCs indicated? 

YES: Troubleshoot the ECM/PCM DTCs.  

NO: Go to step 6.  

6. Perform the Gauge Control Module Input Test (see GAUGE CONTROL MODULE INPUT TEST ). 

Are all inputs OK? 

YES: Go to step 7.  

NO: Repair the faulty input then recheck for DTCs.  

7. Substitute a known-good gauge control module.  

8. Clear the DTCs using the HDS.  

9. Turn the ignition switch OFF then back to the ON (II).  

10. Start and run the engine for at least 5 seconds then turn the engine off.  

11. Check for DTCs using the HDS. 

Is DTC B1178, B1168 and/or B1169 indicated? 

YES: Replace the ECM/PCM.  

NO: The original gauge control module is faulty; replace the gauge control module (see 
GAUGE CONTROL MODULE REPLACEMENT ).  

DTC B1080: POWER SUPPLY CIRCUIT (IG1 LINE) INPUT ERROR FOR RELAY CONTROL 
MODULE & MICU 

1. Clear the DTCs using the HDS.  

2. Cycle the ignition switch to OFF and then back ON.  

3. Turn the ignition switch ON (II) and wait for 2 seconds or more. 

Is DTC B1080 indicated again? 

YES: Go to step 4.  

NO: Intermittent failure, the relay control module is OK at this time. Check for loose or poor 
connections. If the connections are good, check the battery condition and the charging 
system. See GENERATORS & REGULATORS .  

4. Check the MICU IG1 power supply No. 21 (7.5A) fuse in the under-dash fuse/relay box. 

Is the fuse OK? 

YES: Go to MICU Input Test (see MULTIPLEX INTEGRATED CONTROL UNIT 
INPUT TEST ).  

NO: Replace the fuse and recheck for DTCs. 

 

2004 Acura TSX 

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX

  

 

DTC B1251: COMBINATION SWITCH CONTROL UNIT INTERNAL ERROR 

1. Clear the DTCs using the HDS.  

2. Cycle the ignition switch to OFF and then back ON.  

3. Check for DTCs using the HDS. 

Is DTC B1251 indicated? 

YES: Faulty combination switch control unit; replace the wiper/washer switch.  

NO: Intermittent failure, the CPU in the combination switch control unit is OK at this time. 
Check for loose or poor connections. If the connections are good, check the battery condition 
and the charging system. See GENERATORS & REGULATORS .  

DTC B1255: COMBINATION SWITCH CONTROL UNIT LOST COMMUNICATION WITH MICU 

1. Clear the DTCs using the HDS.  

2. Cycle the ignition switch to OFF and then back ON.  

3. Check for DTCs using the HDS. 

Is DTC B1255 indicated? 

YES: Go to step 4.  

NO: Intermittent failure, MICU is OK at this time. Check for loose or poor connections. If 
the connections are good, check the battery condition and the charging system. See 
GENERATORS & REGULATORS .  

4. Check for DTCs in the combination switch control using the HDS. 

Is DTC B1055 and B1157 indicated? 

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

NO: Replace the combination switch control unit.  

MULTIPLEX INTEGRATED CONTROL UNIT INPUT TEST 

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

2. Disconnect the under-dash fuse/relay box connectors D, E, H, I, J, K, N, P and X. 

NOTE:

All connectors shown in Fig. 41 are wire side of female terminals.

 

2004 Acura TSX 

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX

  

 

Fig. 41: Identifying Multiplex Integrated Control Unit Connector Terminals 

3. Inspect the connector and socket terminals to be sure they are all making good contact. 

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If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system.  

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If the terminals look OK, go to step 4.  

4. With the connectors still disconnected from the under-hood fuse/relay box, make these input tests at the 

connector(s). See Fig. 42 . 

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If any test indicates a problem, find and correct the cause, then recheck the system. 

 

2004 Acura TSX 

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX

  

 

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If all the input tests prove okay, go to step 5.  

Fig. 42: Multiplex Integrated Control Unit Input Test Table 

5. Reconnect the connectors to the under-dash fuse/relay box, and make these input tests at the appropriate 

connectors on the under-dash fuse/relay box. See Fig. 43 . 

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If any test indicates a problem, find and correct the cause, then recheck the system.  

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If all the input tests prove OK, the multiplex integrated control unit must be faulty, replace the 
under-dash fuse/relay box assembly. 

 

2004 Acura TSX 

2004 ACCESSORIES & EQUIPMENT Multiplex Integrated Control System - TSX