Honda Civic. Manual — part 234

Is DTC P2123 indicated in the PGM-FI SYSTEM?

YES -Go to the DTC P2123 troubleshooting in the electronic throttle control
system (ETCS) (see DTC P2123: APP SENSOR A (THROTTLE
POSITION SENSOR D) CIRCUIT HIGH VOLTAGE ).

NO -Go to step 4.

4. Check for DTCs in the A/T SYSTEM with the HDS.

Is DTC P2123 indicated in the A/T SYSTEM?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. If any other DTCs were
indicated, go to the INDICATED DTC'S TROUBLESHOOTING.

5. Update the PCM if it does not have the latest software (see UPDATING THE

PCM ), or substitute a known-good PCM (see SUBSTITUTING THE
PCM ).

6. Turn the ignition switch to ON (II).
7. Clear the DTC with the HDS.
8. Start the engine, and wait for at least 2 minutes.
9. Check for DTCs the A/T SYSTEM with the HDS.

Is DTC P2123 indicated in the A/T SYSTEM?

YES -Check for poor connections or loose terminals at the PCM. If the PCM
was updated, substitute a known-good PCM (see SUBSTITUTING THE
PCM ), then go to step 8. If the PCM was substituted, go to step 1.

NO -Go to step 10.

10. Monitor the OBD STATUS for P2123 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED?

2008 Honda Civic LX

2006-08 TRANSMISSION Automatic Transmission - Civic (Except Hybrid)

YES -If the PCM was updated, troubleshooting is complete. If the PCM was
substituted, replace the original PCM (see ECM/PCM REPLACEMENT ). If
any other DTCs were indicated in step 9, go to the INDICATED DTC'S
TROUBLESHOOTING.

NO -If the HDS indicates FAILED, check for poor connections or loose
terminals at the PCM. If the PCM was updated, substitute a known-good PCM
(see SUBSTITUTING THE PCM ), then go to step 8. If the PCM was
substituted, go to step 1. If the HDS indicates NOT COMPLETED, go to step
8.

DTC U0028: F-CAN Malfunction (BUS-OFF (PCM))

1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Check for Temporary DTCs or DTCs in the PGM-FI SYSTEM with the HDS.

Is DTC U0155 indicated in the PGM-FI SYSTEM?

YES -Go to the DTC U0155 troubleshooting in the PGM-FI system (see DTC
U0155: F-CAN MALFUNCTION (ECM/PCM-GAUGE CONTROL
MODULE) ).

NO -Go to step 4.

4. Check for DTCs in the A/T SYSTEM with the HDS.

Is DTC U0028 indicated in he A/T SYSTEM?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. If any other DTCs were

NOTE:

Before you troubleshoot, record all freeze data and any on-
board snapshot with the HDS, and review General
Troubleshooting Information (see GENERAL
TROUBLESHOOTING INFORMATION ).

2008 Honda Civic LX

2006-08 TRANSMISSION Automatic Transmission - Civic (Except Hybrid)

indicated, go to the INDICATED DTC'S TROUBLESHOOTING.

5. Update the PCM if it does not have the latest software (see UPDATING THE

PCM ), or substitute a known-good PCM (see SUBSTITUTING THE
PCM ).

6. Start the engine, and wait for at least 2 minutes.
7. Check for DTCs in the A/T SYSTEM with the HDS.

Is DTC U0028 indicated in the A/T SYSTEM?

YES -Check for poor connections or loose terminals at the PCM. If the PCM
was updated, substitute a known-good PCM (see SUBSTITUTING THE
PCM ), then go to step 6. If the PCM was substituted, go to step 1.

NO -Go to step 8.

8. Monitor the OBD STATUS for U0028 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED?

YES -If the PCM was updated, troubleshooting is complete. If the PCM was
substituted, replace the original PCM (see ECM/PCM REPLACEMENT ). If
any other DTCs were indicated in step 7, go to the INDICATED DTC'S
TROUBLESHOOTING.

NO -If the HDS indicates FAILED, check for poor connections or loose
terminals at the PCM. If the PCM was updated, substitute a known-good PCM
(see SUBSTITUTING THE PCM ), then go to step 6. If the PCM was
substituted, go to step 1. If the HDS indicates NOT COMPLETED, go to step
6.

DTC U0121: F-CAN Malfunction (PCM-ABS)

NOTE:

Before you troubleshoot, record all freeze data and any on-
board snapshot with the HDS, and review General
Troubleshooting Information (see GENERAL
TROUBLESHOOTING INFORMATION ).

2008 Honda Civic LX

2006-08 TRANSMISSION Automatic Transmission - Civic (Except Hybrid)

1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Check for Temporary DTCs or DTCs in the PGM-FI SYSTEM with the HDS.

Is DTC U0155 indicated in the PGM-FI SYSTEM?

YES -Go to the DTC U0155 troubleshooting in the PGM-FI system (see DTC
U0155: F-CAN MALFUNCTION (ECM/PCM-GAUGE CONTROL
MODULE) ).

NO -Go to step 4.

4. Check for DTCs in the A/T SYSTEM with the HDS.

Is DTC U0121 indicated in the A/T SYSTEM?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. If any other DTCs were
indicated, go to the INDICATED DTC'S TROUBLESHOOTING.

5. Update the PCM if it does not have the latest software (see UPDATING THE

PCM ), or substitute a known-good PCM (see SUBSTITUTING THE
PCM ).

6. Start the engine, and wait for at least 2 minutes.
7. Check for DTCs in the A/T SYSTEM with the HDS.

Is DTC U0121 indicated in the A/T SYSTEM?

YES -Check for poor connections or loose terminals at the PCM. If the PCM
was updated, substitute a known-good PCM (see SUBSTITUTING THE
PCM ), then go to step 6. If the PCM was substituted, go to step 1.

NO -Go to step 8.

8. Monitor the OBD STATUS for U0121 in the DTCs MENU with the HDS.

2008 Honda Civic LX

2006-08 TRANSMISSION Automatic Transmission - Civic (Except Hybrid)