DTC B1826: Power Seat Front Up-down Motor Pulse Error

NOTE:

If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnostic Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).
DTC B1826 is, even when the system is OK, stored when the front up-down switch is operated more than one second after the seat moves to the most up or most down position.

Turn the ignition switch OFF, and then back ON (II).
Clear the DTCs with the HDS.
Operate the power seat adjustment switch in all directions for more than 2 seconds,
Check for DTCs with the HDS.
Is DTC B1826 indicated?

YES - Go to step 5.

NO - Intermittent failure. The front up-down position sensor is OK at this time. Check for loose or poor connections at the power seat control unit connector.
Check for DTCs with the HDS.
Is DTC B1836 also indicated?

YES - Go to DTC B1836 troubleshooting (see DTC B1836: POWER SEAT POSITION SENSOR CIRCUIT SHORT ).

NO - Go to step 6.
Check for DTCs with the HDS.
Are DTCs B1825, B1827, and/or B1828 also indicated?

YES - Go to step 16.

NO - Go to step 7.
Operate the front up-down switch for 2 seconds and check the front up-down motor operation.
Does the front up-down motor run smoothly?

YES - Go to step 8.

NO - Go to step 24.
Turn the ignition switch OFF.
Disconnect power seat control unit connector A (40P).
Disconnect the front up-down motor/position sensor 5P connector.
Check for continuity between power seat control unit connector A (40P) No. 12 and No. 29 terminals and front up-down motor/position sensor 5P connector No. 1 and No. 4 terminals.

Fig 1: Checking Continuity Between Power Seat Control Unit Connector A (40P) No. 12 And No. 29 Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 12.

NO - Repair an open in the wire.
Check for continuity between power seat control unit connector A (40P) No. 12 terminal and body ground.

Fig 2: Checking Continuity Between Power Seat Control Unit Connector A (40P) No. 12 Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Repair a short in the wire.

NO - Go to step 13.
Reconnect power seat control unit connector A (40P).
Turn the ignition switch ON (II).
Measure the voltage between the front up-down motor/position sensor 5P connector No. 3 (+) and No. 4 (-) terminals.

Fig 3: Measuring Voltage Between Front Up-Down Motor/Position Sensor 5P Connector No. 3 (+) And No. 4 (-) Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES - Replace the front up-down motor/position sensor.

NO - Check for an open in the WHT/BLK wire. If the wire is OK, substitute a known-good power seat control unit. If the problem is repaired, replace the power seat control unit.
Turn the ignition switch OFF.
Disconnect power seat control unit connector A (40P).
Disconnect the slide position sensor 3P connector.
Check for continuity between power seat control unit connector A (40P) No. 15 and No. 29 terminals and slide position sensor 3P connector No. 3 and No. 2 terminals.

Fig 4: Checking Continuity Between Power Seat Control Unit Connector A (40P) No. 15 And No. 29 Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 20.

NO - Repair an open in the wire.
Disconnect the slide position sensor 3P connector and each 5P connector from the recline motor/ position sensor and the rear up-down motor/ position sensor.
Check for continuity between front up-down motor/ position sensor 5P connector terminal No. 3 and body ground.

Fig 5: Checking Continuity Between Front Up-Down Motor/ Position Sensor 5P Connector Terminal No. 3 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Repair a short in the wire.

NO - Go to step 22.
Reconnect power seat control unit connector A (40P), then turn the ignition switch ON (II).
Measure the voltage between power seat control unit connector A (40P) No. 15 and No. 29 terminals.

Fig 6: Measuring Voltage Between Power Seat Control Unit Connector A (40P) No. 15 And No. 29 Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage when the front up-down switch is operated?

YES - Replace the front up-down motor/position sensor.

NO - Replace the power seat control unit.
Turn the ignition switch OFF.
Disconnect power seat control unit connector B (18P).
Disconnect the front up-down motor/position sensor 5P connector.
Check for continuity between power seat control unit connector B(18P) No. 6 and No; 16 terminals and the front up-down motor/position sensor 5P connector No. 5 and No. 2 terminals.

Fig 7: Checking Continuity Between Power Seat Control Unit Connector B(18P) No. 6 And No; 16 Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 28.

NO - Repair an open in the wire.
Check for continuity between the front up-down motor/position sensor 5P connector No. 2 and No. 5 terminals and body ground.

Fig 8: Checking Continuity Between Front Up-Down Motor/Position Sensor 5P Connector Terminals And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Repair a short in the wire.

NO - Go to step 29.
Do the front up-down motor test (see DRIVER'S POWER SEAT MOTOR TEST ).
Is the motor OK?

YES - Replace the power seat control unit.

NO - Replace the front-up-down motor/position sensor.