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 Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A )
DTC B1826 is stored when the front up-down switch is operated more than 1 second after the seat moves to the most up or most down position, even when the system is OK

Clear the DTCs with the HDS
Turn the ignition switch to LOCK (0) and then back to ON (II)
Operate the power seat adjustment switch in all directions for more than 1 second each
Check for the DTCs with the HDS
Is DTC B1826 indicated?

YES -Go to step 5

NO -Intermittent failure, the system is OK at this time Check for loose or poor connections
Clear the DTCs with the HDS
Is DTC B1836 also indicated?

YES -Go to the DTC B1836: Power Seat Position Sensor Circuit Short

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

YES -Go to step 17

NO -Go to step 7
Turn the ignition switch to LOCK (0) and then back to ON (II)
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 9

NO -Go to step 26
Turn the ignition switch to LOCK (0)
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) terminals No 12 and No 29 and front up-down motor/position sensor 5P connector terminals No 4 and No 5 respectively

Fig 1: Checking Continuity Between Power Seat Control Unit Connector A (40P) And Front Up-Down Motor/Position Sensor 5P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 13

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

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

Is there continuity?

YES -Repair a short to ground in the wire

NO -Go to step 14
Reconnect power seat control unit connector A (40P)
Turn the ignition switch to ON (II)
Measure the voltage between front up-down motor/position sensor 5P connector terminals No 5 (+) and No 4 (-)

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

Is there about 5 V?

YES -Replace the front up-down motor/position sensor (see FRONT SEAT UP-DOWN MOTOR REPLACEMENT )

NO -If there is no voltage, replace the power seat control unit (see POWER SEAT CONTROL UNIT INPUT TEST/REPLACEMENT ) If there is battery voltage, repair a short in the wire (sensor line)
Turn the ignition switch to LOCK (0)
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) terminals No 15 and No 29 and front up-down motor/position sensor 5P connector terminals No 3 and No 4 respectively

Fig 4: Checking Continuity Between Power Seat Control Unit Connector A (40P) And Front Up-Down Motor/Position Sensor 5P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 21

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

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

Is there continuity?

YES -Repair a short to ground in the wire

NO -Go to step 23
Reconnect power seat control unit connector A (40P)
Turn the ignition switch to ON (II)
Measure the voltage between power seat control unit connector A (40P) terminals No 15 and No 29

Fig 6: Measuring Voltage Between Power Seat Control Unit Connector A (40P) Terminals No 15 And No 29
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 (see FRONT SEAT UP-DOWN MOTOR REPLACEMENT )

NO -Replace the power seat control unit (see POWER SEAT CONTROL UNIT INPUT TEST/REPLACEMENT )
Turn the ignition switch to LOCK (0)
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) terminals No 6 and No 16 and front up-down motor/position sensor 5P connector terminals No 1 and No 2 respectively

Fig 7: Checking Continuity Between Power Seat Control Unit Connector B (18P) And Front Up-Down Motor/Position Sensor 5P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 30

NO -Repair an open in the wire
Check for continuity between body ground and front up-down motor/position sensor 5P connector terminals No 1 and No 2 individually

Fig 8: Checking Continuity Between Front Up-Down Motor/Position Sensor 5P Connector Terminals No 1 And No 2 Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short to ground in the wire

NO -Go to step 31
Test the front up-down motor (see DRIVER'S POWER SEAT MOTOR TEST )
Is the motor OK?

YES -Replace the power seat control unit (see POWER SEAT CONTROL UNIT INPUT TEST/REPLACEMENT )

NO -Replace the front up-down motor/position sensor (see FRONT SEAT UP-DOWN MOTOR REPLACEMENT )