DTC B2284: Brake Signal Correlation

DTC detecting condition: 

The status continues for 20 seconds where brake signals (ON/OFF) between direct line and CAN do not match with ignition switch ON.

Trouble symptom: 

If the hard-wired brake signal is faulty, the engine will not start with a normal operation.

Wiring diagram: 

Stop light system Ref. to WIRING SYSTEM>STOP LIGHT SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK LAN SYSTEM  .

   Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

   Is the check result OK?

   Yes  : Go to  2 .

   No  : Perform the inspection according to the diagnosis for LAN system.

2. CHECK DATA MONITOR  .
   1. Turn the ignition switch to ON.
   2. Using the Subaru Select Monitor, check the following items in the [Data Monitor] of [Keyless Access with Push Button Start(Power Supply)]. Ref. to Keyless Access With Push Button Start System (Diagnostics)>Data Monitor .
   • Stop Light Switch

   Does the display change correctly according to the brake pedal operation?

   Yes  : Go to  3 .

   No  : Check the stop light system.

3. CHECK DATA MONITOR  .

   Using the Subaru Select Monitor, check the following items in the [Data Monitor] of [Body Control]. Ref. to BODY CONTROL (DIAGNOSTICS)>DATA MONITOR .

   • Stop Light Switch

   Does the display change correctly according to the brake pedal operation?

   Yes  : Go to  4 .

   No  : Check body integrated unit. Ref. to BODY CONTROL (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE . And check the stop light switch circuit.

4. CHECK FUSE  .
   1. Turn the ignition switch to OFF.
   2. Check the fuse. Ref. to SECURITY AND LOCKS>RELAY AND FUSE>INSPECTION .

   Is the check result OK?

   Yes  : Go to  5 .

   No  : Replace the fuse. When the replaced fuse is blown immediately, check the power supply circuit for short-circuited.

5. CHECK HARNESS  .
   1. Disconnect the keyless access control module connector.
   2. Using a tester, measure the voltage between the keyless access control module connector and chassis ground.

      Connector and terminal 

      (i91) No. 1 (+) - Chassis ground (-):

      (i91) No. 4 (+) - Chassis ground (-):

   Is the voltage 9.5 - 16 V?

   Yes  : Go to  6 .

   No  : Check the power supply circuit.

6. CHECK HARNESS (OPEN CIRCUIT)  .

   Using a tester, measure the resistance between the keyless access control module connector and chassis ground.

   Connector and terminal 

   (i92) No. 17 - Chassis ground:

   (i91) No. 20 - Chassis ground:

   Is the resistance less than 1 Ω?

   Yes  : Go to  7 .

   No  : Repair or replace the open circuit of harness.

7. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Disconnect the stop light switch connector.
   2. Using a tester, measure the resistance between the keyless access control module connector and stop light switch connector.

      Connector and terminal 

      (i92) No. 27 - (B101) No. 2:

   Is the resistance less than 1 Ω?

   Yes  : Go to  8 .

   No  : Repair or replace the open circuit of harness.

8. CHECK HARNESS (GROUND SHORT CIRCUIT)  .

   Using a tester, measure the resistance between the keyless access control module connector and chassis ground.

   Connector and terminal 

   (i92) No. 27 - Chassis ground:

   Is the resistance 10 kΩ or more?

   Yes  : Go to  9 .

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

9. CHECK HARNESS  .

   Using a tester, measure the voltage between the keyless access control module connector and chassis ground when the brake pedal is depressed.

   Connector and terminal 

   (i92) No. 27 (+) - Chassis ground (-):

   Does the voltage change as follows? Brake pedal not depressed: voltage of 1 V or less → Brake pedal depressed: voltage of 11 - 14 V

   Yes  : Replace the keyless access control module. Ref. to SECURITY AND LOCKS>KEYLESS ACCESS CONTROL MODULE>REMOVAL .

   No  : Check the power supply circuit of stop light switch.