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.

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. 

   Using the Subaru Select Monitor, check the following items in the [Data Monitor] of [Keyless Access with Push Button Start]. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START (DIAGNOSTICS)>DATA MONITOR .

   • Stop Light Switch

   Is DTC displayed normally 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

   Is DTC displayed normally according to the brake pedal operation?

   Yes  : Go to  4.

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

4. CHECK FUSE. 

   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 

      (i75) No. 1 (+) - Chassis ground (-):

      (i75) 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 

   (i241) No. 17 - Chassis ground:

   (i75) 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 

      (i241) No. 27 - (B65) 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 

   (i241) 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 

   (i241) No. 27 (+) - Chassis ground (-):

   Does the voltage change as follows? Brake pedal not depressed: 1 V or less → Brake pedal depressed: 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.