DTC B1386: Power Tailgate Sensor Pulse A Circuit Malfunction

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 the motor does not operate, do the power tailgate motor test (see POWER TAILGATE MOTOR TEST ).

Open the tailgate with the tailgate outer handle.
Close the tailgate automatically with the keyless transmitter or inside tailgate switch.
Turn the ignition switch to LOCK (0) and then back to ON (II).
Clear the DTCs with the HDS.
Check for DTCs with the HDS.
Is DTC B1386 indicated?

YES -Go to step 6.

NO -Intermittent failure, the system is OK at this time. Check for loose or poor connections between the power tailgate control unit and the drive unit.
Turn the ignition switch to LOCK (0).
Connect the voltmeter to power tailgate control unit connector B (20P) terminals No. 14 and No. 18.
Measure the voltage between power tailgate control unit connector B (20P) terminals No. 14 and No. 18 while the tailgate is opening and closing with the keyless transmitter or inside tailgate switch.

Fig 1: Measuring Voltage Between Connector B (20P) Terminals No. 14 And No. 18
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Does it alternate between about 0 V and 5 V with an analog voltmeter, or is about 2.5 Vindicated with a digital voltmeter?

YES -Replace the power tailgate control unit.

NO -Go to step 9.
Disconnect power tailgate control unit connector B (20P).
Disconnect drive unit connector B (8P).
Check for continuity between power tailgate control unit connector B (20P) terminal No. 14 and body ground.

Fig 2: Checking Continuity Between Connector B (20P) Terminal No. 14 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 12.
Check for continuity between power tailgate control unit connector B (20P) terminals No. 14 and No. 18 and drive unit connector B (8P) terminals No. 5 and No. 8 respectively.

Fig 3: Checking Continuity Between Connector B (20P) Terminals And Connector B (8P) Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Faulty power tailgate sensor A, replace the drive unit.

NO -Repair an open in the wire.