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 ).

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.
NOTE: 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 down position, even when the system is OK.
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 TROUBLESHOOTING .

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. 5 and No. 4 respectively.

Fig 1: Checking Continuity Between Power Seat Control Unit Connector A (40P) Terminals 12 And 29

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 Body Ground And Power Seat Control Unit Connector A (40P) Terminal No. 12

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 5 And 4

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) Terminals No. 15 And No. 29

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 front up-down motor/position sensor 5P connector terminal No. 3.

Fig 5: Checking Continuity Between Body Ground And Front Up-Down Motor/Position Sensor 5P Connector Terminal No. 3

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

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. 2 and No. 1 respectively.

Fig 7: Checking Continuity Between Power Seat Control Unit Connector B (18P) Terminals No. 6 And No. 16

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 Body Ground And Front Up-Down Motor/Position Sensor 5P Connector Terminals No. 1 And No. 2

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 ).