Multiplex Integrated Control System: Overview Honda Civic IX

Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2

Test Mode 1

Check the ECM/PCM for DTCs and troubleshoot ECM/PCM or F-CAN loss of communication errors first, then do this diagnosis if the HDS is not available.

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1. Check the No. A29 (10 A) fuse in the under-hood fuse/relay box and the No. B5 (7.5 A) fuse in the under-dash fuse/relay box. If the fuse is blown, find and correct the cause, then replace the fuse.
2. Move the interior light switch to the DOOR position. NOTE: Do steps 3 to 7 within 10 seconds.
3. Turn the ignition switch to ON (II).
4. Pull and hold the combination light switch in its Passing position.
5. While holding the switch, turn on the headlights, then release, pull, and hold the combination switch in its Passing position.
6. Turn off the headlights, then turn the headlights ON and OFF two times.
7. Release the combination light switch.
8. Wait 5 seconds, and watch the individual map lights, ceiling light, and ignition key light. When the lights flash quickly once and then go off, the system is in Test Mode 1.
9. Check for B-CAN DTCs indicated by the information display or multi-information display while still in Test Mode 1. Press the SEL/RESET button to display the next code. After you get to the last code, the display shows END. If no DTCs are stored, the display reads NO. NOTE: If the test times out, turn the ignition switch to LOCK (0), and repeat steps 3 to 7 .
10. Record all DTCs and troubleshoot them in this order: Battery voltage DTCs Internal error DTCs Loss of communication DTCs Signal error DTCs
11. Clear the DTCs by pressing and holding the SEL/RESET button for about 10 seconds.
12. You will hear a beep to confirm the codes have been cleared. Operate the devices that failed, and recheck for codes. Test Mode 2 NOTE: Do steps 13 to 17 within 10 seconds.
13. Pull and hold the combination light switch in its Passing position.
14. While holding the switch, turn on the headlights, then release, pull, and hold the combination switch in its Passing position.
15. Turn off the headlights, then turn the headlights ON and OFF two times.
16. Release the combination light switch.
17. Wait 5 seconds, and watch the individual map lights and ignition key light. When the lights flash two times quickly and then go off, the system is in Test Mode 2. NOTE: If you repeat this procedure, the system automatically returns to Test Mode 1.
18. The following tables list the circuits that can be checked in Test Mode 2. Operate the switch that is most closely related to the problem. If the circuit is OK, the individual map lights, ceiling light, and ignition key light blink once. If the circuit is faulty, there is no such indication. If the front individual map lights, ceiling light, and ignition key light do not blink even when a switch is operated, check two or three other circuits listed in the table. If the front individual map lights, ceiling light, and ignition key light blink for each circuit, the additional circuits are OK; repair the short or open circuit that failed the test in step 18. If the front individual map lights, ceiling light, and ignition key light do not blink again, this means that the control unit has failed without triggering a DTC. Test a few more circuits. If they also fail, check the related control units using their input tests. Driver's door lock switch (UNLOCK) Windshield wiper MIST switch Driver's door lock switch (LOCK) Windshield wiper intermittent dwell time controller Front Passenger's door lock switch (UNLOCK) Windshield washer switch Front Passenger's door lock switch (LOCK) Windshield wiper motor park position (Auto stop) Driver's door lock knob switch (UNLOCK) Turn signal switch (LEFT) Driver's door lock knob switch (LOCK) Turn signal switch (RIGHT) Driver's door key cylinder switch (UNLOCK) (1) Hazard warning switch Driver's door key cylinder switch (LOCK) (1) Headlight switch (ON) Front passenger's door lock knob switch (UNLOCK) Headlight switch (OFF) Left rear door lock knob switch (UNLOCK) Lighting switch Right rear door lock knob switch (UNLOCK) Dimmer switch Driver's door switch Passing switch Front passenger's door switch Fog light switch Left rear door switch Ignition key switch Right rear door switch Security hood switch Trunk lid latch switch Brake pedal position switch Audio switch Transmission range switch (P) (A/T) Windshield wiper HI/LO switch A/C pressure switch Windshield wiper INT/LO switch Back-up light switch (M/T) (1) A second key is necessary to check the key cylinder inputs. Be sure to rotate the key cylinder switch two times to each position (lock and lock, unlock and unlock) to ensure the door lock knob switch is in the appropriate position.

Test Mode 1

Check the PCM for DTCs and troubleshoot PCM or F-CAN loss of communication errors first, then do the test below if the HDS is not available.

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1. Check the No. A29 (10 A) fuse in the under-hood fuse/relay box and the No. B5 (7.5 A) fuse in the under-dash fuse/relay box. If a fuse is blown, find and correct the cause, then replace the fuse.
2. Move the interior light switch to the DOOR position. NOTE: Do steps 3 - 7 within 10 seconds.
3. Turn the ignition switch to ON (II).
4. Pull and hold the combination light switch in its Passing position.
5. While holding the switch, turn on the headlights, then release, pull, and hold the combination switch in its Passing position.
6. Turn off the headlights, then turn the headlights ON and OFF two times.
7. Release the combination light switch.
8. Wait 5 seconds, and watch the individual map lights, ceiling light, and ignition key light. When the lights flash quickly once and then go off, the system is in Test Mode 1.
9. Check for B-CAN DTCs indicated by the information display or multi-information display while still in Test Mode 1. Press the SEL/RESET button to display the next code. After you get to the last code, the display shows END. If no DTCs are stored, the display reads NO. NOTE: If the test times out, turn the ignition switch to LOCK (0), and repeat steps 3 - 7 .
10. Record all DTCs and troubleshoot them in this order: Battery voltage DTCs Internal error DTCs Loss of communication DTCs Signal error DTCs
11. Clear the DTCs by pressing and holding the SEL/RESET button for about 10 seconds.
12. You will hear a beep to confirm the codes have been cleared. Operate the devices that failed, and recheck for codes. Test Mode 2 NOTE: Do steps 13 - 17 within 10 seconds.
13. Pull and hold the combination light switch in its Passing position.
14. While holding the switch, turn on the headlights, then release, pull, and hold the combination switch in its Passing position.
15. Turn off the headlights, then turn the headlights ON and OFF two times.
16. Release the combination light switch.
17. Wait 5 seconds, and watch the individual map lights and ignition key light. When the lights flash two times quickly and then go off, the system is in Test Mode 2. NOTE: If you repeat this procedure, the system automatically returns to Test Mode 1.
18. The following tables list the circuits that can be checked in Test Mode 2. Operate the switch that is most closely related to the problem. If the circuit is OK, the individual map lights, ceiling light, and ignition key light blink once. If the circuit is faulty, there is no such indication. If the front individual map lights, ceiling light, and ignition key light do not blink even when a switch is operated, check two or three other circuits listed in the table. If the front individual map lights, ceiling light, and ignition key light blink for each circuit, the additional circuits are OK; repair the short or open circuit that failed the test in step 18. If the front individual map lights, ceiling light, and ignition key light do not blink again, this means that the control unit has failed without triggering a DTC. Test a few more circuits. If they also fail, check the related control units using their input tests. Driver's door lock switch (UNLOCK) Windshield wiper INT/LO switch Driver's door lock switch (LOCK) Windshield wiper MIST switch Front passenger's door lock switch (UNLOCK) Windshield washer switch Front passenger's door lock switch (LOCK) Windshield wiper motor park position (Auto stop) Driver's door lock knob switch (UNLOCK) Turn signal switch (LEFT) Driver's door lock knob switch (LOCK) Turn signal switch (RIGHT) Driver's door key cylinder switch (UNLOCK) (1) Hazard warning switch Driver's door key cylinder switch (LOCK) (1) Headlight switch (ON) Front passenger's door lock knob switch (UNLOCK) Headlight switch (OFF) Left rear door lock knob switch (UNLOCK) Lighting switch Right rear door lock knob switch (UNLOCK) Dimmer switch Driver's door switch Passing switch Front passenger's door switch Ignition key switch Left rear door switch Security hood switch Right rear door switch Fuel fill door switch Trunk lid latch switch Brake pedal position switch Trunk lid outer handle switch Transmission range switch (P) Audio switch A/C pressure switch Windshield wiper HI/LO switch (1) A second key is necessary to check the key cylinder inputs. Be sure to rotate the key cylinder switch two times to each position (lock and lock, unlock and unlock) to ensure the door lock knob switch is in the appropriate position.

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1. F-CAN circuit resistance check: 1. Turn the ignition switch to LOCK (0). 2. Jump the SCS line with the HDS. 3. Disconnect the following connector. ECM/PCM connector A (49P) 4. Disconnect the HDS. 5. Measure the resistance between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Test circuit F_CAN-H, F_CAN-L Test point 1 ECM/PCM connector A (49P) No. 3 (WHT) Test point 2 ECM/PCM connector A (44P) No. 4 (RED) Is there about 46-58 ohms? YES: Go to step 10 . NO: Go to step 2.
2. Shorted wire check (F_CAN-H line to F_CAN-L line): 1. Disconnect the following connectors. Gauge control module (tach) 32P connector VSA modulator-control unit 22P connector Steering angle sensor 4P connector EPS control unit connector A (11P) SRS unit connector A (39P) TPMS control unit 20P connector Audio-navigation unit connector B (20P) (with navigation) 2. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H, F_CAN-L Test point 1 ECM/PCM connector A (49P) No. 3 (WHT) Test point 2 ECM/PCM connector A (44P) No. 4 (RED) Is there continuity? YES: Repair a short in the F_CAN-H wire to F_CAN-L wire between ECM/PCM terminals A3 and A4. NO: The F_CAN-H wire and F_CAN-L wire is not shorted. Go to step 4 .
3. Open wire check (F_CAN-H line) 1: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H Test point 1 ECM/PCM connector A (49P) No. 3 (WHT) Test point 2 Gauge control module (tach) 32P connector No. 19 (WHT) Is there continuity? YES: The F_CAN-L wire is not open. Go to step 8 . NO: Repair an open in the F_CAN-L wire between the ECM/PCM (A4) and the gauge control module (tach).
4. Open wire check (F_CAN-H line) 2: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H Test point 1 ECM/PCM connector A (49P) No. 3 (WHT) Test point 2 VSA modulator-control unit 22P connector No. 10 (WHT) Is there continuity? YES: The F_CAN-H wire is not open. Go to step 5. NO: Repair an open in the F_CAN-H wire between the ECM/PCM (A3) and the VSA modulator-control unit.
5. Open wire check (F_CAN-H line) 3: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H Test point 1 ECM/PCM connector A (49P) No. 3 (WHT) Test point 2 EPS control unit connector A (11P) No. 10 (WHT) Is there continuity? YES: The F_CAN-H wire is not open. Go to step 6. NO: Repair an open in the F_CAN-H wire between the ECM/PCM (A3) and the EPS control unit.
6. Open wire check (F_CAN-L line) 1: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-L Test point 1 ECM/PCM connector A (49P) No. 4 (RED) Test point 2 Gauge control module (tach) 32P connector No. 20 (RED) Is there continuity? YES: The F_CAN-L wire is not open. Go to step 7. NO: Repair an open in the F_CAN-L wire between the ECM/PCM (A4) and the gauge control module (tach).
7. Open wire check (F_CAN-L line) 2: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-L Test point 1 ECM/PCM connector A (49P) No. 4 (RED) Test point 2 VSA modulator-control unit 22P connector No. 15 (RED) Is there continuity? YES: The F_CAN-L wire is not open. Go to step 8. NO: Repair an open in the F_CAN-L wire between the ECM/PCM (A4) and the VSA modulator-control unit.
8. Open wire check (F_CAN-L line) 3: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-L Test point 1 ECM/PCM connector A (49P) No. 4 (RED) Test point 2 EPS control unit connector A (11P) No. 11 (RED) Is there continuity? YES: The F_CAN-L wire is not open. Go to step 9. NO: Repair an open in the F_CAN-L wire between the ECM/PCM (A4) and the EPS control unit.
9. VSA modulator-control unit internal resistance check: 1. Reconnect the VSA modulator-control unit 22P connector. 2. Measure the resistance between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H, F_CAN-L Test point 1 ECM/PCM connector A (49P) No. 3 (WHT) Test point 2 ECM/PCM connector A (44P) No. 4 (RED) Is there about 108-132 ohms? YES: The VSA modulator-control unit is OK. Go to step 10. NO: Substitute a known-good VSA modulator-control unit, then reconnect ECM/PCM connector A (49P). If the HDS identifies the vehicle, replace the original VSA modulator-control unit. See «VSA Modulator-Control Unit Removal and Installation (Natural Gas models)»(ref-614105-S03179738822014050700000) or «VSA Modulator-Control Unit Removal and Installation (Except Natural Gas models)»(ref-614105-S13791155292014050700000)
10. Shorted wire check (F_CAN-H line): 1. Disconnect the following connectors: Gauge control module (tach) 32P connector VSA modulator-control unit 22P connector Steering angle sensor 4P connector EPS control unit connector A (11P) SRS unit connector A (39P) TPMS control unit 20P connector Audio-navigation unit connector B (20P) (with navigation) 2. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H Test point 1 ECM/PCM connector A (49P) No. 3 (WHT) Test point 2 Body ground Is there continuity? YES: Repair a short in the F_CAN-H wire between ECM/PCM (A3) and the gauge control module (tach), the VSA modulator-control unit, the steering angle sensor, the EPS control unit, the SRS unit, the TPMS control unit, the navigation unit, or the DLC. NO: The F_CAN-H wire is OK. Go to step 11.
11. Shorted wire check (F_CAN-L line): 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM/PCM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-L Test point 1 ECM/PCM connector A (49P) No. 4 (RED) Test point 2 Body ground Is there continuity? YES: Repair a short in the F_CAN-L wire between ECM/PCM (A4) and the gauge control module (tach), the VSA modulator-control unit, the steering angle sensor, the EPS control unit, the SRS unit, the TPMS control unit, the audio-navigation unit, or the DLC. NO: The F_CAN-L wire is OK. Go to step 12.
12. Gauge control module (tach) check: 1. Reconnect all connectors. 2. Connect the HDS to the DLC. 3. Disconnect the following connector. Gauge control module (tach) 32P connector 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: Replace the gauge control module (tach) See «GAUGE CONTROL MODULE (SPEEDO) REMOVAL AND INSTALLATION»(ref-614110-S22536531082014050700000) , «GAUGE CONTROL MODULE (TACH) REMOVAL AND INSTALLATION»(ref-614110-S24253527182014050700000) or «REWRITING THE ODO DATA AND TRANSFERRING THE MAINTENANCE MINDER™ DATA TO A NEW GAUGE CONTROL MODULE»(/honda/civic/ix-2011-2015/remont/procedures/#maintenance) . NO: Go to step 13.
13. VSA modulator-control unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the gauge control module (tach) 32P connector. 3. Disconnect the following connector. VSA modulator-control unit 22P connector 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: Replace the VSA modulator-control unit. See «VSA Modulator-Control Unit Removal and Installation (Natural Gas models)»(ref-614105-S03179738822014050700000) or «VSA Modulator-Control Unit Removal and Installation (Except Natural Gas models)»(ref-614105-S13791155292014050700000) NO: Go to step 14.
14. Steering angle sensor check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the VSA modulator-control unit 22P connector. 3. Disconnect the following connector. Steering angle sensor 4P connector 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: «REPLACE THE STEERING ANGLE SENSOR»(ref-614102-S40309629742014050700000) . NO: Go to step 15.
15. EPS control unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the steering angle sensor 4P connector. 3. Disconnect the following connector. EPS control unit connector A (11P) 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: Replace the EPS control unit See «EPS CONTROL UNIT REMOVAL AND INSTALLATION»(ref-614139-S25577756252014050700000) or «EPS CONTROL UNIT UPDATE»(ref-614139-S31189937192014050700000) . NO: Go to step 16.
16. SRS unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the EPS control unit connector A (11P). 3. Disconnect the following connector. SRS unit connector A (39P) 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: Replace the SRS unit See «SRS UNIT REMOVAL AND INSTALLATION»(ref-614100-S25619564512014050700000) or «SRS UNIT UPDATE»(ref-614100-S04605491592014050700000) . NO: With navigation: Go to step 17. NO: Without navigation: Go to step 18 .
17. Audio-navigation unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the SRS unit connector A (39P). 3. Disconnect the following connector. Audio-navigation unit connector B (20P) 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: «REPLACE THE AUDIO-NAVIGATION UNIT»(/honda/civic/ix-2011-2015/remont/entertainment-systems/#audio-system-service-information) . NO: Go to step 18.
18. TPMS control unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the audio-navigation unit connector B (20P). 3. Disconnect the following connector. TPMS control unit 20P connector 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: «REPLACE THE TPMS CONTROL UNIT»(ref-614152-S13014690172014050700000) . NO: Update the ECM/PCM See «ECM REMOVAL AND INSTALLATION (K24Z7)»(ref-614093-S42243049962014050700000) , «ECM/PCM REMOVAL AND INSTALLATION (Except K24Z7 and R18Z1 (CVT)»(ref-614093-S04499420502014050700000) or ECM/PCM UPDATE if it does not have the latest software, or substitute a known-good ECM/PCM See «ECM REMOVAL AND INSTALLATION (K24Z7)»(ref-614093-S42243049962014050700000) , «ECM/PCM REMOVAL AND INSTALLATION (Except K24Z7 and R18Z1 (CVT)»(ref-614093-S04499420502014050700000) or ECM/PCM UPDATE , then recheck. If the HDS identifies the vehicle and the ECM/PCM was updated, troubleshooting is complete. If the HDS identifies the vehicle and the ECM/PCM was substituted, replace the original ECM/PCM See «ECM REMOVAL AND INSTALLATION (K24Z7)»(ref-614093-S42243049962014050700000) , «ECM/PCM REMOVAL AND INSTALLATION (Except K24Z7 and R18Z1 (CVT)»(ref-614093-S04499420502014050700000) or ECM/PCM UPDATE .

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1. F-CAN circuit resistance check: 1. Turn the ignition switch to LOCK (0). 2. Jump the SCS line with the HDS. 3. Disconnect the following connector. ECM connector A (49P) 4. Disconnect the HDS. 5. Measure the resistance between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Test circuit F_CAN-H, F_CAN-L Test point 1 ECM connector A (49P) No. 3 (WHT) Test point 2 ECM connector A (44P) No. 4 (RED) Is there about 46-58 ohms? YES: Go to step 2. NO: Go to step 10
2. Shorted wire check (F_CAN-H line to F_CAN-L line): 1. Disconnect the following connectors. Gauge control module (tach) 32P connector VSA modulator-control unit 22P connector Steering angle sensor 4P connector EPS control unit connector A (11P) SRS unit connector A (39P) TPMS control unit 20P connector Audio-navigation unit connector B (20P) (with navigation) 2. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H, F_CAN-L Test point 1 ECM connector A (49P) No. 3 (WHT) Test point 2 ECM connector A (44P) No. 4 (RED) Is there continuity? YES: Repair a short in the F_CAN-H wire to F_CAN-L wire between ECM terminals A3 and A4. NO: The F_CAN-H wire and F_CAN-L wire is not shorted. Go to step 3.
3. Open wire check (F_CAN-H line) 1: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H Test point 1 ECM connector A (49P) No. 3 (WHT) Test point 2 Gauge control module (tach) 32P connector No. 19 (WHT) Is there continuity? YES: The F_CAN-H wire not open. Go to step 4. NO: Repair an open in the F_CAN-H wire between the ECM (A3) and the gauge control module (tach).
4. Open wire check (F_CAN-H line) 2: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H Test point 1 ECM connector A (49P) No. 3 (WHT) Test point 2 VSA modulator-control unit 22P connector No. 10 (WHT) Is there continuity? YES: The F_CAN-H wire is not open. Go to step 5. NO: Repair an open in the F_CAN-H wire between the ECM (A3) and the VSA modulator-control unit.
5. Open wire check (F_CAN-H line) 3: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H Test point 1 ECM connector A (49P) No. 3 (WHT) Test point 2 EPS control unit connector A (11P) No. 10 (WHT) Is there continuity? YES: The F_CAN-H wire is not open. Go to step 6. NO: Repair an open in the F_CAN-H wire between the ECM (A3) and the EPS control unit.
6. Open wire check (F_CAN-L line) 1: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-L Test point 1 ECM connector A (49P) No. 4 (RED) Test point 2 Gauge control module (tach) 32P connector No. 20 (RED) Is there continuity? YES: The F_CAN-L wire is not open. Go to step 7. NO: Repair an open in the F_CAN-L wire between the ECM (A4) and the gauge control module (tach).
7. Open wire check (F_CAN-L line) 2: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-L Test point 1 ECM connector A (49P) No. 4 (RED) Test point 2 VSA modulator-control unit 22P connector No. 15 (RED) Is there continuity? YES: The F_CAN-L wire is not open. Go to step 8. NO: Repair an open in the F_CAN-L wire between the ECM (A4) and the VSA modulator-control unit.
8. Open wire check (F_CAN-L line) 3: 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-L Test point 1 ECM connector A (49P) No. 4 (RED) Test point 2 EPS control unit connector A (11P) No. 11 (RED) Is there continuity? YES: The F_CAN-L wire is not open. Go to step 9. NO: Repair an open in the F_CAN-L wire between the ECM (A4) and the EPS control unit.
9. VSA unit internal resistance check: 1. Reconnect VSA modulator-control unit 22P connector. 2. Measure the resistance between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H, F_CAN-L Test point 1 ECM connector A (49P) No. 3 (WHT) Test point 2 ECM connector A (44P) No. 4 (RED) Is there about 108-132 ohms? YES: The VSA modulator-control unit is OK. Go to step 10. NO: Substitute a known-good VSA modulator-control unit, then reconnect ECM connector A (49P). If the HDS identifies the vehicle, replace the original VSA modulator-control unit. See «VSA Modulator-Control Unit Removal and Installation (Natural Gas models)»(ref-614105-S03179738822014050700000) or «VSA Modulator-Control Unit Removal and Installation (Except Natural Gas models)»(ref-614105-S13791155292014050700000)
10. Shorted wire check (F_CAN-H line): 1. Disconnect the following connectors: Gauge control module (tach) 32P connector VSA modulator-control unit 22P connector Steering angle sensor 4P connector EPS control unit connector A (11P) SRS unit connector A (39P) TPMS control unit 20P connector Audio-navigation unit connector B (20P) (with navigation) 2. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-H Test point 1 ECM connector A (49P) No. 3 (WHT) Test point 2 Body ground Is there continuity? YES: Repair a short in the F_CAN-H wire between ECM (A3) and the gauge control module (tach), the VSA modulator-control unit, the steering angle sensor, the EPS control unit, the SRS unit, the TPMS control unit, the navigation unit, or the DLC. NO: The F_CAN-H wire is OK. Go to step 11.
11. Shorted wire check (F_CAN-L line): 1. Check for continuity between test points 1 and 2. Test condition IG LOCK (0) Test circuit F_CAN-L Test point 1 ECM connector A (49P) No. 4 (RED) Test point 2 Body ground Test condition IG LOCK (0) ECM connector A (49P): disconnected Gauge control module (tach) 32P connector: disconnected VSA modulator-control unit 22P connector: disconnected Steering angle sensor 4P connector: disconnected EPS control unit connector A (11P): disconnected SRS unit connector A (39P): disconnected TPMS control unit 20P connector: disconnected Audio-navigation unit connector B (20P) (with navigation): disconnected Test circuit F_CAN-L Test point 1 ECM connector A (49P) No. 4 (RED) Test point 2 Body ground Is there continuity? YES: Repair a short in the F_CAN-L wire between ECM (A4) and the gauge control module (tach), the VSA modulator-control unit, the steering angle sensor, the EPS control unit, the SRS unit, the TPMS control unit, the navigation unit, or the DLC. NO: The F_CAN-L wire is OK. Go to step 12.
12. Gauge control module (tach) check: 1. Reconnect all connectors. 2. Connect the HDS to the DLC. 3. Disconnect the following connector. Gauge control module (tach) 32P connector 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: Replace the gauge control module (tach) See «GAUGE CONTROL MODULE (SPEEDO) REMOVAL AND INSTALLATION»(ref-614110-S22536531082014050700000) , «GAUGE CONTROL MODULE (TACH) REMOVAL AND INSTALLATION»(ref-614110-S24253527182014050700000) or «REWRITING THE ODO DATA AND TRANSFERRING THE MAINTENANCE MINDER™ DATA TO A NEW GAUGE CONTROL MODULE»(/honda/civic/ix-2011-2015/remont/procedures/#maintenance) . NO: Go to step 13.
13. VSA modulator-control unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the gauge control module (tach) 32P connector. 3. Disconnect the following connector. VSA modulator-control unit 22P connector 4. Turn the ignition switch to ON (II). Does the HDS identify the vehicle? YES: Replace the VSA modulator-control unit. See «VSA Modulator-Control Unit Removal and Installation (Natural Gas models)»(ref-614105-S03179738822014050700000) or «VSA Modulator-Control Unit Removal and Installation (Except Natural Gas models)»(ref-614105-S13791155292014050700000) NO: Go to step 14.
14. Steering angle sensor check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the VSA modulator-control unit 22P connector. 3. Disconnect the following connector. Steering angle sensor 4P connector 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: «REPLACE THE STEERING ANGLE SENSOR»(ref-614102-S40309629742014050700000) . NO: Go to step 15.
15. EPS control unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the steering angle sensor 4P connector. 3. Disconnect the following connector. EPS control unit connector A (11P) 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: Replace the EPS control unit See «EPS CONTROL UNIT REMOVAL AND INSTALLATION»(ref-614139-S25577756252014050700000) or «EPS CONTROL UNIT UPDATE»(ref-614139-S31189937192014050700000) . NO: Go to step 16.
16. SRS unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the servo unit 25P connector. 3. Disconnect the following connector. SRS unit connector A (39P) 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: Replace the SRS unit See «SRS UNIT REMOVAL AND INSTALLATION»(ref-614100-S25619564512014050700000) or «SRS UNIT UPDATE»(ref-614100-S04605491592014050700000) . NO: With navigation: Go to step 17. NO: Without navigation: Go to step 18 .
17. Audio-navigation unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the SRS unit connector A (39P). 3. Disconnect the following connector. Audio-navigation unit connector B (20P) 4. Turn the ignition switch to ON (II), and read the HDS. Does the HDS identify the vehicle? YES: Replace the audio-navigation unit. NO: Go to step 18.
18. TPMS control unit check: 1. Turn the ignition switch to LOCK (0). 2. Reconnect the audio-navigation unit connector B (20P). 3. Disconnect the following connector. TPMS control unit 20P connector 4. Turn the ignition switch to ON (II) and read the HDS. Does the HDS identify the vehicle? YES: Replace the TPMS control unit. NO: «UPDATE THE ECM/PCM»(ref-614093-S31920981662014050700000) if it does not have the latest software, or «SUBSTITUTE A KNOWN-GOOD ECM»(ref-614093-S31920981662014050700000) , then recheck. If the HDS identifies the vehicle and the ECM was updated, troubleshooting is complete. If the HDS identifies the vehicle and the ECM was substituted, «REPLACE THE ORIGINAL ECM»(ref-614093-S31920981662014050700000) .

See also:
• REWRITING THE ODO DATA AND TRANSFERRING THE MAINTENANCE MINDER™ DATA TO A NEW GAUGE CONTROL MODULE
• REPLACE THE AUDIO-NAVIGATION UNIT
• DISCONNECT THE AUTOMATIC LIGHTING CONTROL UNIT 14P CONNECTOR
• RESET THE MOONROOF BEFORE PROCEEDING
• MOONROOF MOTOR REMOVAL AND INSTALLATION (2-DOOR)