Power Supply and Ground Circuit Check

Power Supply and Ground Circuit Check

Diagnosis Procedure

1. INSPECTION START

Start engine.

Is engine running?

Yes or No
Yes
GO TO 8.
No
GO TO 2.

2. CHECK ECM POWER SUPPLY CIRCUIT-I

1 Turn ignition switch OFF and then ON.
2 Check voltage between ECM terminal 109 and ground with SDT or tester.











OK or NG
OK
GO TO 4.
NG
GO TO 3.

3. DETECT MALFUNCTIONING PART

Check the following.
- Fuse block (J/B) connector M4
- Harness connectors M31, E152
- 10 A fuse (No.1)
- Harness for open or short between ECM and fuse


Repair harness or connectors.

4. CHECK GROUND CONNECTIONS

1 Turn ignition switch OFF.
2 Loosen and retighten three ground screws on the body. Refer to "Ground Inspection".






OK or NG
OK
GO TO 5.
NG
Repair or replace ground connections.

5. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I

1 Disconnect ECM harness connector.
2 Check harness continuity between ECM terminals 1, 115, 116 and ground.
Refer to Wiring Diagram.






3 Also check harness for short to power.

OK or NG
OK
GO TO 7.
NG
GO TO 6.

6. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors F32, E2
- Harness for open or short between ECM and ground


Repair open circuit or short to power in harness or connectors.

7. CHECK ECM POWER SUPPLY CIRCUIT-II

1 Reconnect ECM harness connector.
2 Turn ignition switch ON.
3 Check voltage between IPDM E/R connector E119 terminal 3 and ground with SDT or tester.











OK or NG
OK
Go to [Ignition Signal Circuit Check] Testing and Inspection.
NG
GO TO 8.

8. CHECK ECM POWER SUPPLY CIRCUIT-III

1 Turn ignition switch OFF and wait at least 10 seconds.
2 Turn ignition switch ON and then OFF.
3 Check voltage between ECM terminals 119, 120 and ground with SDT or tester.











OK or NG
OK
GO TO 13.
NG (Battery voltage does not exist.)
GO TO 9.
NG (Battery voltage exists for more than a few seconds.)
ERROR! Unknown action!GO TO 11.

9. CHECK ECM POWER SUPPLY CIRCUIT-IV

Check voltage between ECM terminal 111 and ground with SDT or tester.











OK or NG
OK
GO TO 10.
NG
GO TO 11.

10. CHECK ECM POWER SUPPLY CIRCUIT-V

1 Disconnect ECM harness connector.
2 Disconnect IPDM E/R harness connector E119.
3 Check harness continuity between ECM terminals 119, 120 and IPDM E/R terminal 4.
Refer to Wiring Diagram.






4 Also check harness for short to ground and short to power.

OK or NG
OK
GO TO 16.
NG
Repair open circuit or short to ground or short to power in harness or connectors.

11. CHECK ECM POWER SUPPLY CIRCUIT-VI

1 Disconnect ECM harness connector.
2 Disconnect IPDM E/R harness connector E119.
3 Check harness continuity between ECM terminal 111 and IPDM E/R terminal 7.
Refer to Wiring Diagram.






4 Also check harness for short to ground and short to power.

OK or NG
OK
GO TO 12.
NG
Repair open circuit or short to ground or short to power in harness or connectors.

12. CHECK 20 A FUSE

1 Disconnect 20 A fuse (No.53) from IPDM E/R.
2 Check 20 A fuse.

OK or NG
OK
GO TO 16.
NG
Replace 20 A fuse.

13. CHECK GROUND CONNECTIONS

Loosen and retighten three ground screws on the body. Refer to "Ground Inspection".






OK or NG
OK
GO TO 14.
NG
Repair or replace ground connections.

14. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II

1 Check harness continuity between ECM terminals 1, 115, 116 and ground.
Refer to Wiring Diagram.






2 Also check harness for short to power.

OK or NG
OK
GO TO 16.
NG
GO TO 15.

15. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors F32, E2
- Harness for open or short between ECM and ground


Repair open circuit or short to power in harness or connectors.

16. CHECK INTERMITTENT INCIDENT

Refer to [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.

OK or NG
OK
Replace IPDM E/R. Refer to [IPDM E/R: Removal and Installation of IPDM E/R] Service and Repair.
NG
Repair open circuit or short to power in harness or connectors.

Ground Inspection

Ground connections are very important to the proper operation of electrical and electronic circuits. Ground connections are often exposed to moisture, dirt and other corrosive elements. The corrosion (rust) can become an unwanted resistance. This unwanted resistance can change the way a circuit works.

Electronically controlled circuits are very sensitive to proper grounding. A loose or corroded ground can drastically affect an electronically controlled circuit. A poor or corroded ground can easily affect the circuit. Even when the ground connection looks clean, there can be a thin film of rust on the surface.

When inspecting a ground connection follow these rules:

- Remove the ground bolt or screw.
- Inspect all mating surfaces for tarnish, dirt, rust, etc.
- Clean as required to assure good contact.
- Reinstall bolt or screw securely.
- Inspect for "add-on" accessories which may be interfering with the ground circuit.
- If several wires are crimped into one ground eyelet terminal, check for proper crimps. Make sure all of the wires are clean, securely fastened and providing a good ground path. If multiple wires are cased in one eyelet make sure no ground wires have excess wire insulation.

For detailed ground distribution information, refer to [Service Information for Electrical Incident: Circuit Inspection] Service Information for Electrical Incident: Circuit Inspection.