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

DTC detecting condition:

When any of the following continued for 20 seconds on the model with Auto Start Stop while the ignition switch is ON.

The engine speed signal of direct line is less than 200 rpm, and also the engine speed signal of CAN is 1000 rpm or more.
The engine speed signal of direct line is 1000 rpm or more, and also the engine speed signal of CAN is less than 200 rpm.

CAUTION:

For replacement procedure of keyless access Control Module, refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume.
Before performing diagnosis, refer to "CAUTION" in "General Description". Refer to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .

Wiring diagram:

Push button start system. Refer to WIRING SYSTEM>PUSH BUTTON START SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CHECK LAN SYSTEM.
Perform the diagnosis for LAN system. Refer 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.
CHECK COMBINATION METER.
Confirm that the speedometer is displayed normally.

Is the display of combination meter OK?

Yes: Go to 3.

No: Perform the diagnosis for the engine. Refer to ENGINE (DIAGNOSTICS) (W/O STI)>DIAGNOSTICS FOR ENGINE STARTING FAILURE>PROCEDURE . Refer to ENGINE (DIAGNOSTICS) (STI)>DIAGNOSTICS FOR ENGINE STARTING FAILURE>PROCEDURE .
CHECK DATA MONITOR.
Using the Subaru Select Monitor, check the following items on «Data monitor» of «Keyless Access with Push Button Start». Refer to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (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.
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
  
  (B573) No. 6 - (B134) No. 4:
Is the resistance less than 1 Ω?

Yes: Go to 5.

No: Repair or replace the open circuit of harness.
CHECK HARNESS (GROUND SHORT CIRCUIT).
Using a tester, measure the resistance between the keyless access Control Module connector and chassis ground.

Connector & terminal

(B573) 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.
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
  
  (B573) 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) (W/O STI)>DIAGNOSTICS FOR ENGINE STARTING FAILURE>PROCEDURE . Refer to ENGINE (DIAGNOSTICS) (STI)>DIAGNOSTICS FOR ENGINE STARTING FAILURE>PROCEDURE .