DTC B2511: Rotation Sensor Pulse/Reverse Direction

DTC detecting condition: 

When output of the power rear gate drive unit rotation sensor is different from the direction that it should be.

Trouble symptom: 

Auto-operation does not function.

Wiring diagram: 

Power rear gate system Ref. to WIRING SYSTEM>POWER REAR GATE SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK AUTO OPERATION  .
   1. Turn the ignition switch to OFF.
   2. Using operation switch, perform power rear gate auto open/close operation from full close position or full open position.

   Does it work as fully open → fully close, and fully close → fully open?

   Yes:  Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.

   No:  Go to  2 .

2. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Read the DTC of [Power Rear Gate] using the Subaru Select Monitor. Ref. to Power Rear Gate (Diagnostics)>Diagnostic Trouble Code (DTC) .

   Is DTC B2511 displayed? (Current malfunction)

   Yes:  Go to  3 .

   No:  Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
3. CHECK DATA MONITOR  .
   1. Activate the auto closer to a fully closed position.
   2. Check [Pulse-count 2] in fully closed and fully open status using Subaru Select Monitor. Ref. to Power Rear Gate (Diagnostics)>Data Monitor .
      NOTE: When confirming the data monitor, display only one item to be checked at a time. When the displayed items are too many, changes in the pulses will not be retrieved.

   Does the pulse count increase during the open operation? Does the pulse count decrease during the close operation?

   Yes:  Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.

   No:  Go to  4 .

4. CHECK ROTATION SENSOR SIGNAL  .

   Using an oscilloscope, measure the waveform between Power rear gate drive unit connectors.

   Connector and terminal 

   (L136) No. 3 (+) - (L136) No. 6 (-):

   (L136) No. 2 (+) - (L136) No. 6 (-):

   Does the voltage change when the power rear gate is manually opened/closed? (Approx. 0 V ←→ Approx. 12 V)

   Yes:  Go to  5 .

   No:  Replace Power rear gate drive unit. Ref. to POWER REAR GATE SYSTEM>POWER REAR GATE DRIVE UNIT .

5. CHECK Power rear gate drive unit  .

   Using an oscilloscope, measure the waveform between Power rear gate drive unit connectors.

   Connector and terminal 

   (L136) No. 3 (+) - (L136) No. 5 (-):

   (L136) No. 2 (+) - (L136) No. 5 (-):

   Does the waveform change as noted in the margin when the power rear gate is manually opened/closed?

   Yes:  Go to  6 .

   No:  Replace Power rear gate drive unit. Ref. to POWER REAR GATE SYSTEM>POWER REAR GATE DRIVE UNIT .

6. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the Power rear gate control module connector.
   3. Disconnect the Power rear gate drive unit connector.
   4. Measure the resistance between Power rear gate control module connector and Power rear gate drive unit connector.

      Connector and terminal 

      (L86) No. 8 - (L136) No. 6:

      (L86) No. 9 - (L136) No. 2:

      (L86) No. 10 - (L136) No. 3:

      (L86) No. 11 - (L136) No. 5:

   Is the resistance less than 10 Ω?

   Yes:  Go to  7 .

   No:  Repair or replace the open circuit of harness.

7. CHECK HARNESS (GROUND SHORT CIRCUIT)  .

   Measure the resistance between Power rear gate control module connector and chassis ground.

   Connector and terminal 

   (L86) No. 9 - Chassis ground:

   (L86) No. 10 - Chassis ground:

   (L86) No. 11 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes:  Go to  8 .

   No:  Repair or replace the short circuit of the harness.

8. CHECK HARNESS (SHORT CIRCUIT TO POWER SUPPLY)  .

   Measure the voltage between Power rear gate control module connector and chassis ground.

   Connector and terminal 

   (L86) No. 9 - Chassis ground:

   (L86) No. 10 - Chassis ground:

   (L86) No. 11 - Chassis ground:

   Is the voltage less than 1 V?

   Yes:  Replace Power rear gate control module. Ref. to POWER REAR GATE SYSTEM>POWER REAR GATE CONTROL MODULE .

   No:  Repair or replace the short circuit of the harness.