DTC P1659: Electronic Throttle Control System (ETCS) Control Relay OFF Malfunction

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting malfunction (see GENERAL TROUBLESHOOTING INFORMATION ).

Turn the ignition switch 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, system is OK at this time. Check for poor connections or loose terminals at the ETCS control relay and the PCM.
Turn the ignition switch OFF.
Check the No. 7 DBW (THROTTLE ACTUATOR CONTROL) (15 A) fuse in the auxiliary under-hood fuse box.
Is the fuse OK?

YES - Go to step 6.

NO - Go to step 20.
Remove the ETCS control relay (A).

Fig 1: Removing ETCS Control Relay
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Test the ETCS control relay (see POWER RELAY TEST ).
Is the ETCS control relay OK?

YES - Go to step 8.

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

Fig 2: Measuring Voltage Between ETCS Control Relay 4P Connector Terminal No. 4 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES - Go to step 10.

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

Fig 3: Measuring Voltage Between ETCS Control Relay 4P Connector Terminal No. 1 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the battery voltage?

YES - Go to step 11.

NO - Repair open in the wire between the ETCS control relay and the No. 7 DBW (THROTTLE ACTUATOR CONTROL) (15 A) fuse in the auxiliary under-hood fuse box, then go to step 25.
Turn the ignition switch OFF.
Jump the SCS line with the HDS.
Disconnect PCM connector C (44P).
Connect ETCS control relay 4P connector terminal No. 2 to body ground with a jumper wire.

Fig 4: Connecting ETCS Control Relay 4P Connector Terminal No. 2 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between PCM connector terminal C4 and body ground.

Fig 5: Checking For Continuity Between PCM Connector Terminal C4 & 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 ETCS control relay, then go to step 26.
Disconnect the jumper wire.
Disconnect PCM connector A (44P).
Connect ETCS control relay 4P connector terminal No. 3 to body ground with a jumper wire.

Fig 6: Connecting ETCS Control Relay 4P Connector Terminal No. 3 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between PCM connector terminal A20 and body ground.

Fig 7: Checking For Continuity Between PCM Connector Terminal A20 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 32.

NO - Repair open in the wire between the PCM (A20) and the ETCS control relay, then go to step 26.
Remove the ETCS control relay (A).

Fig 8: Removing ETCS control relay
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Jump the SCS line with the HDS.
Disconnect PCM connector C (44P).
Check for continuity between PCM connector terminal C4 and body ground.

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

Is there continuity?

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

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

Fig 10: Checking For Continuity Between ETCS Control Relay 4P Connector Terminal No. 1 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Repair short in the wire between the No. 7 DBW (THROTTLE ACTUATOR CONTROL) (15 A) fuse and the ETCS control relay, then go to step 26.

NO - Replace the No. 7 DBW (THROTTLE ACTUATOR CONTROL) (15 A) fuse, then go to step 26.
Turn the ignition switch OFF.
Reconnect all connectors.
Turn the ignition switch 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 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 UPDATING AND SUBSTITUTION FOR TESTING ), or substitute a known-good PCM (see HOW TO SUBSTITUTE THE PCM ).
Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1659 indicated?

YES - Check poor connections or loose terminals at the ETCS control relay and the PCM. If the PCM was updated, subtitute a known-good PCM (see HOW TO SUBSTITUTE 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 .