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Home >> Subaru >> 2016 >> WRX Premium, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 9 (Engine Controls (Diagnostics) (H4DOTC) (WRX-STI)) >> Diagnostics for Engine Starting Failure >> Starter Motor Circuit >> Wiring Diagram

Starter Motor Circuit: Wiring Diagram

WARNING: This page is about a different variant/trim than selected.

Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) Ref. to the appropriate SYSTEM WIRING diagram article. ENGINE TYPE EJ (WITHOUT PUSH BUTTON START).

Fig 1: Engine Electrical System - Wiring Diagram (Engine Type EJ)
G10265798Courtesy of SUBARU OF AMERICA, INC.
DIAGNOSTIC PROCEDURE

Step Check Yes No
1 CHECK BATTERY. 
Check the battery. < Ref. to INSPECTION , 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 INPUT SIGNAL FOR STARTER MOTOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from starter motor.
  3. Depress the clutch pedal.
  4. Turn the ignition switch to START.
  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 5. 
5 CHECK INPUT SIGNAL FOR STARTER MOTOR. 
  1. Depress the clutch pedal.
  2. Turn the ignition switch to START.
  3. Measure the voltage between starter relay connector and chassis ground.

    Connector & terminal 

    (B225) No. 1 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Repair the open circuit of the harness between starter relay connector and starter motor. Go to step 6. 
6 CHECK HARNESS BETWEEN BATTERY AND IGNITION SWITCH CONNECTOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from ignition switch.
  3. Measure the voltage between ignition switch connector and chassis ground.

    Connector & terminal 

    (B72) No. 4 (+) - Chassis ground (-): 

    (B72) No. 5 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Go to step 7.  Repair the power supply circuit.
7 CHECK IGNITION SWITCH. 
Measure the resistance between ignition switch terminals after turning the ignition switch to START position.
Terminals 
No. 3 - No. 4: 
No. 5 - No. 7: 		 Is the resistance less than 1 Ω? Go to step 8.  Replace the ignition switch. < Ref. to REPLACEMENT , Ignition Key Lock. >
8 CHECK INPUT VOLTAGE OF CLUTCH START SWITCH. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from clutch start switch.
  3. Connect the connector to ignition switch.
  4. Turn the ignition switch to START.
  5. Measure the voltage between the clutch start switch connector and chassis ground.

    Connector & terminal 

    (B106) No. 1 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Go to step 9.  Check the following item and repair if necessary.
  • Blown out of fuse (F/B No. 21)
  • Open or short circuit to ground in harness between ignition switch connector and clutch start switch connector
9 CHECK HARNESS BETWEEN STARTER RELAY CONNECTOR AND CLUTCH START SWITCH CONNECTOR. 
  1. Turn the ignition switch to OFF.
  2. Remove the starter relay.
  3. Measure the resistance of harness between starter relay connector and clutch start switch connector.

    Connector & terminal 

    (B225) No. 3 - (B106) No. 2: 

 Is the resistance less than 1 Ω? Go to step 10.  Repair the open circuit in harness between starter relay connector and clutch start switch connector.
10 CHECK INPUT VOLTAGE OF STARTER RELAY. 
  1. Connect the connector to the clutch start switch.
  2. Depress the clutch pedal.
  3. Turn the ignition switch to START.
  4. Measure the voltage between starter relay connector and chassis ground.

    Connector & terminal 

    (B225) No. 3 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Go to step 11.  Replace the clutch start switch. < Ref. to CLUTCH SWITCH . >
11 CHECK INPUT VOLTAGE OF STARTER RELAY. 
  1. Turn the ignition switch to START.
  2. Measure the voltage between starter relay connector and chassis ground.

    Connector & terminal 

    (B225) No. 2 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Go to step 12.  Repair the open circuit of harness between starter relay connector and ignition switch connector.
12 CHECK STARTER RELAY. 
  1. Connect the battery to starter relay terminals No. 3 and No. 5.
  2. Measure the resistance between starter relay terminals.

    Terminals 

    No. 1 - No. 2: 

 Is the resistance less than 1 Ω? Go to step 13.  Replace the starter relay.
13 CHECK HARNESS BETWEEN ECM AND STARTER RELAY CONNECTOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from ECM.
  3. Measure the resistance of harness between ECM connector and starter relay connector.

    Connector & terminal 

    (B136) No. 16 - (B225) No. 1: 

 Is the resistance less than 1 Ω? Go to step 14.  Repair the harness and connector.
NOTE: In this case, repair the following item:

  • Open circuit of harness between ECM connector and starter relay connector
  • Blown out of fuse
14 CHECK ECM INPUT VOLTAGE. 
  1. Install the starter relay.
  2. Depress the clutch pedal.
  3. Turn the ignition switch to START.
  4. Measure the voltage between ECM connector and chassis ground.

    Connector & terminal 

    (B135) No. 26 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Check the 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 open circuit of harness between ECM connector and starter relay connector.


Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) Ref. to the appropriate SYSTEM WIRING diagram article. ENGINE TYPE EJ (WITH PUSH BUTTON START).

Fig 1: Engine Electrical System - Wiring Diagram (Engine Type EJ)
G10265799Courtesy of SUBARU OF AMERICA, INC.
DIAGNOSTIC PROCEDURE

Step Check Yes No
1 CHECK BATTERY. 
Check the battery. < Ref. to INSPECTION , 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 clutch pedal.
 Does the ignition turn to ON? Go to step 5.  Check the push button start system. < Ref. to POWER SUPPLY SWITCHING SYSTEM , INSPECTION, General Diagnostic Table. >
5 CHECK PUSH BUTTON IGNITION SWITCH. 
  1. Depress the clutch pedal.
  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 ENGINE DOES NOT START , INSPECTION, Diagnostics with Phenomenon. >
6 CHECK START SWITCH SIGNAL. 
  1. Read the waveform of start switch signal using Subaru Select Monitor.
    NOTE: For detailed operation procedures, refer to "Current Data Display For Engine". < Ref. to SUBARU SELECT MONITOR . >
  2. While depressing the clutch pedal, press the push button ignition switch once.
 Does waveform of the start switch signal occur? Go to step 10.  Go to step 7. 
7 CHECK HARNESS BETWEEN ECM AND KEYLESS ACCESS CM. 
  1. Turn the ignition to OFF.
  2. Disconnect the connectors from ECM and keyless access CM.
  3. Measure the resistance of harness between ECM connector and keyless access CM.

    Connector & terminal 

    (B136) No. 16 - (B572) No. 7: 

 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 CM connector
  • Poor contact of coupling connector
8 CHECK HARNESS BETWEEN ECM AND KEYLESS ACCESS CM. 
Measure the resistance between ECM connector and chassis ground.
Connector & terminal 
(B136) No. 16 - 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 CM connector.
9 CHECK START SWITCH SIGNAL. 
  1. Connect the connector to ECM and keyless access CM.
  2. Read the waveform of start switch signal using an oscilloscope.
  3. While depressing the clutch pedal, press the push button ignition switch once.

    Connector & terminal 

    (B136) No. 16(+) - Chassis ground (-): 

 Does waveform of the start switch signal occur? Repair the poor contact of ECM connector. Repair the poor contact of keyless access CM connector.
10 CHECK INPUT SIGNAL FOR STARTER MOTOR. 
  1. Turn the ignition to OFF.
  2. Disconnect the connector from starter motor.
  3. Place the shift lever in neutral.
  4. While depressing the clutch pedal, press the push button ignition switch once.
  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 STARTERS Go to step 11. 
11 CHECK HARNESS BETWEEN STARTER RELAY CONNECTOR AND STARTER MOTOR CONNECTOR. 
  1. Remove the starter relay.
  2. Measure the resistance of harness between starter relay connector and starter motor connector.

    Connector & terminal 

    (B225) No. 1 - (B14) No. 1: 

 Is the resistance less than 1 Ω? Go to step 12.  Repair the open circuit in harness between starter relay connector and starter motor connector.
12 CHECK IG RELAY 1 (PUSH BUTTON START) POWER SUPPLY. 
  1. Remove the IG relay 1 (push button start).
  2. Turn the ignition to ON.
  3. Measure the voltage between the IG relay 1 (push button start) connector and chassis ground.

    Connector & terminal 

    (B225) No. 37 (+) - Chassis ground (-): 

    (B225) No. 38 (+) - Chassis ground (-): 

 Is the voltage 10 V or more? Go to step 13.  Check the following item and repair or replace if necessary.
  • Blown out of fuse
  • Open circuit or short circuit to ground in harness between IG relay 1 (push button start) connector and keyless access CM connector
  • Open circuit or short circuit to ground in harness between IG relay 1 (push button start) connector and battery
13 CHECK HARNESS BETWEEN IG RELAY 1 (PUSH BUTTON START) CONNECTOR AND CHASSIS GROUND. 
  1. Turn the ignition to OFF.
  2. Measure the resistance of harness between the IG relay 1 (push button start) connector and chassis ground.

    Connector & terminal 

    (B225) No. 39 - Chassis ground: 

 Is the resistance less than 5 Ω? Go to step 14.  Repair the open circuit in harness between the IG relay 1 (push button start) connector and chassis ground.
14 CHECK IG RELAY 1 (PUSH BUTTON START). 
  1. Connect the battery to IG relay 1 (push button start) terminals No. 38 and No. 39.
  2. Measure the resistance between IG relay 1 (push button start) terminals.

    Terminals 

    No. 36 - No. 37: 

 Is the resistance less than 1 Ω? Go to step 15.  Replace the IG relay 1 (push button start). < Ref. to IG RELAY 1 (PUSH BUTTON START) . >
15 CHECK STARTER RELAY (PUSH BUTTON START) POWER SUPPLY. 
  1. Install the IG relay 1 (push button start).
  2. Remove the starter relay (push button start).
  3. Turn the ignition to ON.
  4. Measure the voltage between starter relay (push button start) connector and chassis ground.

    Connector & terminal 

    (B225) No. 29 (+) - Chassis ground (-): 

    (B225) No. 30 (+) - 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 (F/B No. 26)
  • Open circuit or short circuit to ground in harness between starter relay (push button start) connector and IG relay 1 (push button start) connector
  • Open circuit or short circuit to ground in harness between starter relay (push button start) connector and battery
16 CHECK HARNESS BETWEEN STARTER RELAY (PUSH BUTTON START) CONNECTOR AND CHASSIS GROUND. 
  1. Turn the ignition to OFF.
  2. Measure the resistance of harness between starter relay (push button start) connector and chassis ground.

    Connector & terminal 

    (B225) No. 31 - Chassis ground: 

 Is the resistance less than 5 Ω? Go to step 17.  Repair the open circuit in harness between starter relay (push button start) connector and chassis ground.
17 CHECK STARTER RELAY (PUSH BUTTON START). 
  1. Connect the battery to starter relay (push button start) terminals No. 30 and No. 31.
  2. Measure the resistance between starter relay (push button start) terminals.

    Terminals 

    No. 28 - No. 29: 

 Is the resistance less than 1 Ω? Go to step 18.  Replace the starter relay (push button start). < Ref. to STARTER RELAY (PUSH BUTTON START) . >
18 CHECK HARNESS BETWEEN STARTER RELAY (PUSH BUTTON START) CONNECTOR AND STARTER CUT RELAY CONNECTOR. 
  1. Remove the starter cut relay.
  2. Measure the resistance of harness between starter relay (push button start) connector and starter cut relay connector.

    Connector & terminal 

    (B225) No. 28 - (B225) No. 42: 

    (B225) No. 28 - (B225) No. 44: 

 Is the resistance less than 1 Ω? Go to step 19.  Repair the open circuit in harness between starter relay (push button start) connector and starter cut relay connector.
19 CHECK HARNESS BETWEEN ECM AND STARTER CUT RELAY CONNECTOR. 
  1. Disconnect the connector from ECM.
  2. Measure the resistance between starter cut relay connector and chassis ground.

    Connector & terminal 

    (B225) No. 40 - Chassis ground: 

 Is the resistance 1 MΩ or more? Go to step 20.  Repair the short circuit to ground in harness between ECM connector and starter cut relay connector.
20 CHECK STARTER CUT RELAY. 
Measure the resistance between starter cut relay terminals.
Terminals 
No. 41 - No. 44: 		 Is the resistance less than 1 Ω? Go to step 21.  Replace the starter cut relay. < Ref. to STARTER CUT RELAY . >
21 CHECK HARNESS BETWEEN STARTER CUT RELAY CONNECTOR AND 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 

    (B225) No. 41 - (B225) No. 2: 

 Is the resistance less than 1 Ω? Go to step 22.  Repair the open circuit in harness between starter cut relay connector and starter relay connector.
22 CHECK HARNESS BETWEEN STARTER RELAY CONNECTOR AND CLUTCH START SWITCH CONNECTOR. 
Measure the resistance of harness between starter relay connector and clutch start switch connector.
Connector & terminal 
(B225) No. 3 - (B106) No. 2: 		 Is the resistance less than 1 Ω? Go to step 23.  Repair the open circuit in harness between starter relay connector and clutch start switch connector.
23 CHECK HARNESS BETWEEN ECM AND STARTER RELAY CONNECTOR. 
Measure the resistance of harness between ECM connector and starter relay connector.
Connector & terminal 
(B135) No. 26 - (B225) No. 5: 
(B136) No. 27 - (B225) No. 1: 		 Is the resistance less than 1 Ω? Go to step 24.  Repair the harness and connector.
NOTE: In this case, repair the following item:

  • Open circuit of harness between ECM connector and starter relay connector
  • Blown out of fuse
24 CHECK STARTER RELAY. 
  1. Connect the battery to starter relay terminals No. 3 and No. 5.
  2. Measure the resistance between starter relay terminals.

    Terminals 

    No. 1 - No. 2: 

 Is the resistance less than 1 Ω? Check the ECM power supply and ground line. < Ref. to CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MODULE (ECM) , Diagnostics for Engine Starting Failure. > Replace the starter relay. < Ref. to LOCATION , Electrical Component Location. >
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