ECM Power Source Circuit: Procedure

1. Disconnect the ECM connector.
2. Measure the resistance between the terminals.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   B50-81 (E1) - Body ground	Always	Below 1 Ω

3. Reconnect the ECM connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND) 

OK: Go to next step 

1. Disconnect the ECM connector.
   Fig 1: Identifying A55 ECM Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the ignition switch to ON.
3. Measure the voltage between the terminals.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A55-28 (IGSW) - Body ground	Ignition switch ON	11 to 14 V

4. Reconnect the ECM connector.

NG → See step   6 

OK: Go to next step 

1. Inspect the EFI relay. Refer to INSPECTION .

NG → REPLACE ENGINE ROOM JUNCTION BLOCK 

OK: Go to next step 

1. Disconnect the ECM connector.
2. Remove the engine room junction block from the engine room R/B.
3. Disconnect the engine room junction block connector.
4. Measure the resistance between the terminals.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   1D-4 - A55-2 (+B)	Always	Below 1 Ω
   1D-4 - A55-1 (+B2)	Always	Below 1 Ω
   A55-44 (MREL) - 1H-10	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   1D-4 or A55-2 (+B) - Body ground	Always	10 kΩ or higher
   1D-4 or A55-1 (+B2) - Body ground	Always	10 kΩ or higher
   A55-44 (MREL) or 1H-10 - Body ground	Always	10 kΩ or higher

5. Reconnect the engine room junction block connector.
6. Reinstall the engine room junction block.
7. Reconnect the ECM connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the engine room junction block from the engine room R/B.
2. Disconnect the engine room junction block connector.
3. Measure the resistance between the terminals.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1H-2 - Body ground	Always	Below 1 Ω

4. Reconnect the engine room junction block connector.
5. Reinstall the engine room junction block.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM JUNCTION BLOCK - BODY GROUND) 

OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM JUNCTION BLOCK - BATTERY) 

1. Remove the IG2 relay from the engine room R/B.
   Fig 2: Identifying Relay Test Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance the terminals.

   Standard Resistance

   Tester Connection	Specified Condition
   3 - 5	10 kΩ or higher
   3 - 5	Below 1 Ω (Battery voltage applied between terminals 1 and 2)

3. Reinstall the IG2 relay.

NG → REPLACE RELAY (IG2 RELAY) 

OK: Go to next step 

1. Remove the IG2 relay from the engine room R/B.
2. Disconnect the ECM connector.
3. Measure the resistance between the terminals.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   3 (IG2 relay terminal) - A55-28 (IGSW)	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   3 (IG2 relay terminal) or A55-28 (IGSW) - Body ground	Always	10 kΩ or higher

4. Reinstall the IG2 relay.
5. Reconnect the ECM connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - ECM) 

OK: Go to next step 

1. Remove the IG2 relay from the engine room R/B.
2. Measure the voltage between the terminals.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   5 (IG2 relay terminal) - Body ground	Always	11 to 14 V

3. Reinstall the IG2 relay.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BATTERY) 

OK: Go to next step 

1. Remove the IG2 relay from the engine room R/B.
2. Measure the resistance between the terminals.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   2 (IG2 relay terminal) - Body ground	Always	Below 1 Ω

3. Reinstall the IG2 relay.

   Result

   Result	Proceed to
   OK (w/o Smart key system)	A
   OK (w/ Smart key system)	B
   NG	C

B → See step   12 

C → REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BODY GROUND) 

A: Go to next step 

1. Remove the IG2 relay from the engine room R/B.
2. Disconnect the ignition switch assembly connector.
3. Measure the resistance between the terminals.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   1 (IG2 relay terminal) - D30-6 (IG2)	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   1 (IG2 relay terminal) or D30-6 (IG2) - Body ground	Always	10 kΩ or higher

4. Reinstall the IG2 relay.
5. Reconnect the ignition switch assembly connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - IGNITION SWITCH ASSEMBLY) 

OK: Go to next step 

1. Inspect the ignition switch assembly. Refer to INSPECTION .

NG → REPLACE IGNITION SWITCH ASSEMBLY 

OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH ASSEMBLY - BATTERY) 

1. Disconnect the power source control ECU connector.
2. Remove the IG2 relay from the engine room R/B.
3. Measure the resistance between the terminals.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   1 (IG2 relay terminal) - D44-35 (IG2D)	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   1 (IG2 relay terminal) or D44-35 (IG2D) - Body ground	Always	10 kΩ or higher

4. Reconnect the power source control ECU connector.
5. Reinstall the IG2 relay.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - POWER SOURCE CONTROL ECU) 

OK → See step   13