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

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

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 ).
If DTC B1825 and B1826 are both indicated, check for a blown No. 14 (20A) fuse in the under-dash fuse/relay box. If the fuse blows again, check for a short to ground in the front up-down motor circuit.

Turn the ignition switch to LOCK (0) and then back to ON (II).
Clear the DTCs with the HDS.
Operate the power seat adjustment switch in all directions for at least 6 seconds each.
Check for DTCs with the HDS.
Is DTC B1826 indicated?

YES -Go to step 5.

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

YES -Go to the 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 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 position sensor 4P connector.
Check for continuity between power seat control unit connector A (40P) terminals No. 12 and No. 29 and front up-down position sensor 4P connector terminals No. 2 and No. 3 respectively.

Fig 1: Checking Continuity Between Connector (40P) Terminals And 4P Connector Terminals
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 power seat control unit connector A (40P) terminal No. 12 and body ground.

Fig 2: Checking Continuity Between Connector (40P) Terminal 12 And 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 position sensor 4P connector terminals No. 2 (+) and No. 3 (-).

Fig 3: Measuring Voltage Between 4P Connector Terminals No. 2 (+) And No. 3 (-)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 5 V?

YES -Faulty front up-down position sensor, replace the front up-down motor.

NO -If there is no voltage, replace the power seat control unit. 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 position sensor 4P connector.
Check for continuity between power seat control unit connector A (40P) terminals No. 15 and No. 29 and front up-down position sensor 4P connector terminals No. 1 and No. 3 respectively.

Fig 4: Checking Continuity Between Connector (40P) Terminals And 4P Connector Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 21.

NO -Repair an open in the wire.
Disconnect the 4P connector from the slide position sensor and the rear up-down position sensor, then disconnect the driver's seat wire harness 8P [14P] connector.
[]: With seat ventilation
Check for continuity between body ground and front up-down position sensor 4P connector terminal No. 1.

Fig 5: Checking Continuity Between Body Ground And 4P Connector Terminal No. 1
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 Connector (40P) Terminals 15 And 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.

NO -Replace the power seat control unit.
Turn the ignition switch to LOCK (0).
Disconnect power seat control unit connector B (18P).
Disconnect the front up-down motor 2P connector.
Check for continuity between power seat control unit connector B (18P)terminals No. 6 and No. 16 and front up-down motor 2P connector terminals No. 1 and No. 2 respectively.

Fig 7: Checking Continuity Between Connector B (18P) Terminals And 2P Connector Terminals
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 2P connector terminals No. 1 and No. 2 individually.

Fig 8: Checking Continuity Between Body Ground And 2P Connector Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short to ground in the wire.

NO -Go to step 31
Do the front up-down motor test (see SLIDE MOTOR, FRONT UP-DOWN MOTOR. REAR UP-DOWN MOTOR ).
Is the motor OK?

YES -Replace the power seat control unit.

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