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Starter Motor Circuit: Wiring Diagram

Engine Electrical System ENGINE TYPE FB (WITH PUSH BUTTON START) < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: Starter Motor Circuit Diagram (Model With Push Button Start)
G10310226Courtesy of SUBARU OF AMERICA, INC.
DIAGNOSTIC PROCEDURE

Step Check Yes No
1 CHECK BATTERY. 
Check the battery. < Ref. to BATTERY . >		 Is the battery OK? Go to step 2  . Charge or replace the battery. < Ref. to BATTERY . >
2 CHECK OPERATION OF STARTER MOTOR.  Does the starter motor operate? Go to step 3  . Go to step 4  .
3 CHECK DTC.  Is DTC displayed? < Ref. to OPERATION , Read Diagnostic Trouble Code (DTC). > Check the appropriate DTC using the "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . > Check ignition control system. < Ref. to IGNITION CONTROL SYSTEM , Diagnostics for Engine Starting Failure. >
4 CHECK PUSH BUTTON IGNITION SWITCH. 
Press the push button ignition switch twice with the ignition OFF (ACC OFF).
NOTE: Release the brake pedal.
 Does the ignition turn to ON? Go to step 5  . Check the push button start system. < Ref. to INSPECTION , General Diagnostic Table. >
5 CHECK PUSH BUTTON IGNITION SWITCH. 
  1. Depress the brake pedal.
    NOTE: Shift the select lever to "P" range.
  2. Check the push button ignition switch indicator.
 Does the indicator turn to green? Go to step 6  . Check the push button start system. < Ref. to INSPECTION , General Diagnostic Table. >
6 CHECK START SWITCH SIGNAL. 
  1. Read the waveform of «Starter SW» using the Subaru Select Monitor.
    NOTE: For detailed operation procedures, refer to "Read Current Data For Engine". < Ref. to SUBARU SELECT MONITOR . >
  2. Press the push button ignition switch once with the brake pedal depressed.
 Does waveform of the «Starter SW» occur? Go to step 10  . Go to step 7  .
7 CHECK HARNESS BETWEEN ECM AND KEYLESS ACCESS CONTROL MODULE. 
  1. Turn the ignition to OFF.
  2. Disconnect the connectors from ECM and keyless access control module.
  3. Measure the resistance of harness between ECM connector and keyless access control module.

    Connector & terminal 

    (B134) No. 46 - (i241) No. 35: 

 Is the resistance less than 1 Ω? Go to step 8  . Repair the harness and connector.
NOTE: In this case, repair the following item:
  • Open circuit of harness between ECM connector and keyless access control module connector
  • Poor contact of coupling connector
8 CHECK HARNESS BETWEEN ECM AND KEYLESS ACCESS CONTROL MODULE. 
Measure the resistance between ECM connector and chassis ground.
Connector & terminal 
(B134) No. 46 - Chassis ground: 		 Is the resistance 1 MΩ or more? Go to step 9  . Repair the short circuit to ground in harness between ECM connector and keyless access control module connector.
9 CHECK START SWITCH SIGNAL. 
  1. Connect the connector to ECM and keyless access control module.
  2. Read the waveform of start switch signal using an oscilloscope.
  3. Press the push button ignition switch once with the brake pedal depressed.

    Connector & terminal 

    (B134) No. 46 (+) - Chassis ground (-): 

 Does waveform of the start switch signal occur? Repair the poor contact of ECM connector. Repair the poor contact of keyless access control module connector.
10 CHECK INPUT SIGNAL FOR STARTER MOTOR. 
  1. Turn the ignition to OFF.
  2. Disconnect the connector from starter motor.
  3. Place the select lever in "P" range or "N" range.
  4. Press the push button ignition switch once with the brake pedal depressed.
  5. Measure the voltage between the starter motor connector and the engine ground.

    Connector & terminal 

    (B14) No. 1 (+) - Engine ground (-): 

 Is the voltage 10 V or more? Check the starter motor. < Ref. to STARTER . > Go to step 11  .
11 CHECK POWER SUPPLY OF IG2 RELAY. 
  1. Remove the IG2 relay.
  2. Turn the ignition to ON.
  3. Measure the voltage between F/B (IG2 relay) terminal and chassis ground.

    Connector & terminal 

    (B56) No. 8 (+) - Chassis ground (-): 

    (i137) No. 12 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Go to step 12  . Check the following item and repair or replace if necessary.
  • Blown out of fuse (F/B No. 26)
  • Open circuit or short circuit to ground in harness between F/B (IG2 relay) terminal and power supply circuit
  • Open circuit or short circuit to ground in harness between F/B (IG2 relay) terminal and keyless access control module
  • Poor contact of coupling connector
  • Blown out of fuse
12 CHECK F/B (IG2 RELAY). 
Check the F/B (IG2 relay). < Ref. to RELAY AND FUSE . >		 Is the resistance less than 1 Ω? Go to step 13  . Replace the IG2 relay. < Ref. to RELAY AND FUSE . >
13 CHECK POWER SUPPLY OF F/B (IG2 RELAY) CONNECTOR. 
  1. Install the F/B (IG2 relay).
  2. Remove the F/B (IG2 relay) connectors (B158) and (i136).
  3. Measure the voltage between F/B (IG2 relay) terminal and chassis ground.

    Connector & terminal 

    (B158) No. 3 (+) - Chassis ground (-): 

    (i136) No. 6 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Go to step 14  . Replace the F/B unit. < Ref. to VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) . >
14 CHECK HARNESS BETWEEN F/B (IG2 RELAY) TERMINAL AND CHASSIS GROUND. 
  1. Turn the ignition to OFF.
  2. Measure the resistance of harness between the F/B (IG2 relay) connectors (B158) and (i136) and the chassis ground.

    Connector & terminal 

    (B158) No. 3 - Chassis ground: 

    (i136) No. 6 - Chassis ground: 

 Is the resistance less than 5 Ω? Go to step 15  . Repair the open circuit of the harness between F/B (IG2 relay) connector and chassis ground.
15 CHECK POWER SUPPLY OF IG1 RELAY (PUSH BUTTON START). 
  1. Remove the M/B IG1 relay (push button start).
  2. Turn the ignition to ON.
  3. Measure the voltage between the M/B IG1 relay (push button start) terminals No. 1 and No. 2 and the chassis ground.

    Terminals 

    No. 1 (+) - Chassis ground (-): 

    No. 2 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Go to step 16  . Check the following item and repair or replace if necessary.
  • Blown out of fuse
  • Open circuit or short circuit to ground in harness between M/B IG1 relay (push button start) connector and F/B connector
  • Open circuit or short circuit to ground in harness between M/B IG1 relay (push button start) connector and battery
16 CHECK HARNESS BETWEEN M/B IG1 RELAY (PUSH BUTTON START) TERMINAL AND CHASSIS GROUND. 
  1. Turn the ignition to OFF.
  2. Measure the resistance of the harness between M/B IG1 relay (push button start) terminal and chassis ground.

    Terminals 

    No. 4 - Chassis ground: 

 Is the resistance less than 5 Ω? Go to step 17  . Repair the open circuit of the harness between M/B IG1 relay (push button start) connector and chassis ground.
17 CHECK M/B IG1 RELAY (PUSH BUTTON START). 
  1. Connect the battery to M/B IG1 relay (push button start) terminals No. 2 and No. 4.
  2. Measure the resistance between M/B IG1 relay (push button start) terminals.

    Terminals 

    No. 1 - No. 3: 

 Is the resistance less than 1 Ω? Go to step 18  . Replace the M/B IG1 relay (push button start). < Ref. to RELAY AND FUSE . >
18 CHECK HARNESS BETWEEN ECM AND STARTER CUT RELAY CONNECTOR. 
  1. Disconnect the connectors from ECM and starter cut relay.
  2. Measure the resistance between starter cut relay connector and chassis ground.

    Connector & terminal 

    (B220) No. 17 - Chassis ground: 

 Is the resistance 1 MΩ or more? Go to step 19  . Repair the short circuit to ground in harness between ECM connector and starter cut relay connector.
19 CHECK STARTER CUT RELAY. 
Measure the resistance between starter cut relay terminals.
Terminals 
No. 18 - No. 21: 		 Is the resistance less than 1 Ω? Go to step 20  . Replace the starter cut relay. < Ref. to RELAY AND FUSE . >
20 CHECK HARNESS BETWEEN STARTER CUT RELAY CONNECTOR AND F/B (STARTER RELAY) CONNECTOR. 
  1. Remove the starter relay.
  2. Measure the resistance of harness between starter cut relay connector and starter relay connector.

    Connector & terminal 

    (B220) No. 18 - (i137) No. 8: 

 Is the resistance less than 1 Ω? Go to step 21  . Check the following item and repair or replace if necessary.
  • Blown out of fuse (F/B No. 26)
  • Open circuit of harness between starter cut relay connector and F/B (starter relay) connector
21 CHECK F/B (STARTER RELAY). 
Check the F/B (starter relay). < Ref. to STARTER RELAY . >		 Is the resistance less than 1 Ω? Go to step 22  . Replace the starter relay (push button start). < Ref. to STARTER RELAY . >
22 CHECK HARNESS BETWEEN ECM AND F/B (STARTER RELAY) CONNECTOR. 
Measure the resistance of harness between ECM connector and starter relay connector.
Connector & terminal 
(B134) No. 62 - (B158) No. 2: 		 Is the resistance less than 1 Ω? Go to step 23  . Repair the open circuit of harness between ECM connector and starter relay connector.
23 CHECK HARNESS BETWEEN F/B (STARTER RELAY) CONNECTORS (B158) AND (B159). 
  1. Remove the F/B (starter relay).
  2. Measure the resistance between F/B (starter relay) connector (B158) and (B159).

    Terminals 

    (B158) No. 5 - (B159) No. 4: 

 Is the resistance less than 1 Ω? Go to step 24  . Check the fuse (F/B No. 12). If a fault is not found, replace the F/B unit. < Ref. to VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) . >
24 CHECK HARNESS BETWEEN STARTER RELAY CONNECTOR AND INHIBITOR SWITCH CONNECTOR. 
  1. Disconnect the connector from inhibitor switch.
  2. Measure the resistance of harness between starter relay connector and inhibitor switch connector.

    Connector & terminal 

    (B159) No. 4 - (T7) No. 6: 

 Is the resistance less than 1 Ω? Go to step 25  . Repair the harness and connector.
NOTE: In this case, repair the following item:
  • Open circuit in harness between starter relay connector and inhibitor switch connector
  • Poor contact of coupling connector
25 CHECK INHIBITOR SWITCH. 
  1. Place the select lever in "P" range or "N" range.
  2. Measure the resistance between inhibitor switch terminals.

    Terminals 

    No. 6 - No. 9: 

 Is the resistance less than 1 Ω? Go to step 26  . Replace the inhibitor switch. < Ref. to INHIBITOR SWITCH . >
26 CHECK HARNESS BETWEEN ECM AND INHIBITOR SWITCH CONNECTOR. 
  1. Disconnect the connector from ECM.
  2. Measure the resistance of harness between ECM connector and inhibitor switch connector.

    Connector & terminal 

    (B134) No. 5 - (T7) No. 6: 

 Is the resistance less than 1 Ω? Go to step 27  . Repair the harness and connector.
NOTE: In this case, repair the following item:
  • Open circuit in harness between ECM connector and inhibitor switch connector
  • Poor contact of coupling connector
27 CHECK NEUTRAL POSITION SWITCH SIGNAL. 
  1. Connect all relays and connectors to their proper positions.
  2. Read the value of «Neutral Position Switch» using the Subaru Select Monitor.
    NOTE: For detailed operation procedures, refer to "Read Current Data For Engine". < Ref. to SUBARU SELECT MONITOR . >
  3. Turn the ignition to ON.
  4. Place the select lever in "P" range or "N" range.
 Is «Neutral» displayed? Check the engine control module (ECM) power supply and ground line. < Ref. to CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MODULE (ECM) , Diagnostics for Engine Starting Failure. > Repair the harness and connector.
NOTE: In this case, repair the following item:
  • Open circuit in harness between inhibitor switch connector and starter motor connector
  • Poor contact of coupling connector
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