DTC B228A: Engine Speed Signal (With Auto Start Stop)

DTC detecting condition: 

For model with Auto Start Stop, when any of the following conditions continues for 20 seconds with ignition switch ON.

• Engine speed signal on direct line is more than 200 rpm, and engine speed signal on CAN is 1000 rpm or less.
• Engine speed signal on direct line is 1000 rpm or more, and engine speed signal on CAN is less than 200 rpm.

Trouble symptom: 

Cannot start the engine, or the engine stops after starting.

Wiring diagram: 

Keyless access with push button start system. Refer to WIRING SYSTEM (IMPREZA MODEL)>KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM>WIRING DIAGRAM . Refer to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK LAN SYSTEM. 

   Perform the diagnosis for LAN system. Refer to LAN SYSTEM (DIAGNOSTICS) (EXCEPT FOR HEV)>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 COMBINATION METER. 

   Confirm that the speedometer is displayed normally.

   Is combination meter display OK?

   Yes:  Go to  3.

   No:  Perform the diagnosis for the engine. Refer to ENGINE (DIAGNOSTICS) (H4DO (EXCEPT FOR HEV))>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

3. CHECK DATA MONITOR. 

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

   • Engine Speed

   Can the data be read normally?

   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 HARNESS (OPEN CIRCUIT). 
   1. Disconnect the keyless access control module connector.
   2. Disconnect the ECM connector.
   3. Using a tester, measure the resistance between the keyless access control module connector and ECM connector.

      Connector & terminal 

      (i75) No. 6 - (B134) No. 17:

   Is the resistance less than 1 Ω?

   Yes:  Go to  5.

   No:  Repair or replace the open circuit of harness.

5. CHECK HARNESS (GROUND SHORT CIRCUIT). 

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

   Connector & terminal 

   (i75) No. 6 - Chassis ground:

   Is the resistance 10 kΩ or more?

   Yes:  Go to  6.

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

6. CHECK HARNESS. 
   1. Connect the keyless access control module connector and ECM connector.
   2. Using an oscilloscope, measure the waveform between the keyless access control module connector and chassis ground.

      Connector & terminal 

      (i75) No. 6 - Chassis ground:

   Does the pulse stop when the engine is stopped, and does the pulse generate when the engine is started?

   Yes:  Replace the keyless access control module. Refer to SECURITY AND LOCKS>KEYLESS ACCESS control module .

   No:  Perform the diagnosis for the engine. Refer to ENGINE (DIAGNOSTICS) (H4DO (EXCEPT FOR HEV))>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .