DTC B2284: Brake Signal Correlation

DTC detecting condition: 

When mismatch of the brake signals (ON/OFF) of direct line and CAN continued for 20 seconds, when the ignition switch is turned ON.

Trouble symptom: 

If the hard-wired brake signal is faulty, the engine does not start by the normal operation.

Wiring diagram: 

• Keyless access with push button start system Ref. to WIRING SYSTEM>Keyless Access With Push Button Start System>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 on «Data monitor» of «Keyless Access with Push Button Start». Ref. to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (DIAGNOSTICS)>DATA MONITOR .

   «Stop light SW»

   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 on «Body Control» of «Keyless Access with Push Button Start». Ref. to BODY CONTROL SYSTEM (DIAGNOSTICS)>READ CURRENT DATA .

   «Stop light SW»

   Is DTC displayed normally according to the brake pedal operation?

   Yes: Go to  4.

   No: Check body integrated unit Ref. to BODY CONTROL SYSTEM (DIAGNOSTICS)>Basic Diagnostic Procedure>PROCEDURE . and the stop light switch circuit.

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 & 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 & 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 & 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 & 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 & 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.