DTC P1659: ETCS Control Relay OFF Malfunction

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see HOW TO USE THE HDS (HONDA DIAGNOSTIC SYSTEM) ).

Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1659 indicated?

YES - Go to step 4.

NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the electronic throttle control system (ETCS) control relay and the PCM.
Turn the ignition switch to LOCK (0).
Check the No. 3 DBW (15 A) fuse in the passenger's under-dash fuse/relay box.
Is the fuse OK?

YES - Go to step 6.

NO - Go to step 20.
Remove the electronic throttle control system (ETCS) control relay (A) from the passenger's under-dash fuse/relay box.

Fig 1: Identifying Electronic Throttle Control System (ETCS) Control Relay
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Test the electronic throttle control system (ETCS) control relay (see POWER RELAY TEST ).
Is the electronic throttle control system (ETCS) control relay OK?

YES - Go to step 8.

NO - Replace the electronic throttle control system (ETCS) control relay, then go to step 26.
Turn the ignition switch to ON (II).
Measure the voltage between electronic throttle control system (ETCS) control relay 4P connector terminal No. 3 and body ground.

Fig 2: Identifying Voltage Between ETCS Control Relay 4P Connector Terminal 3 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the battery voltage?

YES - Go to step 10.

NO - Repair open in the wire between PGM-FI main relay 1 (Fl MAIN) and the electronic throttle control system (ETCS) control relay, then go to step 25.
Measure the voltage between electronic throttle control system (ETCS) control relay 4P connector terminal No. 1 and body ground.

Fig 3: Identifying Voltage Between ETCS Control Relay 4P Connector Terminal 1 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES - Go to step 11.

NO - Repair open in the wire between the electronic throttle control system (ETCS) control relay and the under-hood fuse/relay box, then go to step 25.
Turn the ignition switch to LOCK(0).
Jump the SCS line with the HDS.
Disconnect PCM connector C (49P).
Connect electronic throttle control system (ETCS) control relay 4P connector terminal No. 2 to body ground with a jumper wire.

Fig 4: Identifying ETCS Control Relay 4P Connector Terminal 2 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between the PCM connector terminal C4 and body ground.

Fig 5: Identifying Continuity Between PCM Connector Terminal C4 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 16.

NO - Repair open in the wire between the PCM (C4) and the electronic throttle control system (ETCS) control relay, then go to step 26.
Disconnect the jumper wire.
Disconnect PCM connector A (49P).
Connect electronic throttle control system (ETCS) control relay 4P connector terminal No. 4 to body ground with a jumper wire.

Fig 6: Identifying ETCS Control Relay 4P Connector Terminal 4 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between PCM connector terminal A29 and body ground.

Fig 7: Identifying Continuity Between PCM Connector Terminal A29 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 31.

NO - Repair open in the wire between the PCM (A29) and the electronic throttle control system (ETCS) control relay, then go to step 26.
Remove the electronic throttle control system (ETCS) control relay (A) from the passenger's under-dash fuse/relay box.

Fig 8: Identifying Electronic Throttle Control System (ETCS) Control Relay
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Jump the SCS line with the HDS.
Disconnect PCM connector C (49P).
Check for continuity between PCM connector terminal C4 and body ground.

Fig 9: Identifying Continuity Between PCM Connector Terminal C4 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Repair short in the wire between the electronic throttle control system (ETCS) control relay and the PCM (C4), then go to step 26.

NO - Go to step 24.
Check for continuity between electronic throttle control system (ETCS) control relay 4P connector terminal No. 1 and body ground.

Fig 10: Identifying Continuity Between ETCS Control Relay 4P Connector Terminal 1 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Replace the passenger's under-dash fuse/ relay box (see REMOVAL AND INSTALLATION ), then go to step 26.

NO - Replace the No. 3 DBW (15 A) fuse, then go to step 31.
Turn the ignition switch to LOCK (0).
Reconnect all connectors.
Turn the ignition switch to ON (II).
Reset the PCM with the HDS.
Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1659 indicated?

YES - Check for poor connections or loose terminals at the electronic throttle control system (ETCS) control relay and the PCM, then go to step 1.

NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC'S TROUBLESHOOTING .
Reconnect all connectors.
Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1659 indicated?

YES - Check for poor connections or loose terminals at the electronic throttle control system (ETCS) control relay and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the PCM was substituted, go to step 1.

NO - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC'S TROUBLESHOOTING .