СИСТЕМА ECD - ECM Power Source Circuit
DESCRIPTION
When the ignition switch is turned to ON, the battery voltage is applied to terminal IGSW of the ECM. The ECM "MREL" output signal causes current to flow to the EFI relay coil, closing the contacts of the EFI relay and supplying power to terminal +B of the ECM.
WIRING DIAGRAM
INSPECTION PROCEDURE
- Inspect the fuses for circuits related to this system before performing the following inspection procedure.
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| G61-12 (+B) - C101-14 (E1) | Ignition switch ON | 11 to 14 V |
Text in Illustration| *a | Component with harness connected
(ECM) |
| OK | |
| |
| PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE
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| 2.CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) |
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
| Tester Connection | Condition | Specified Condition |
| C101-14 (E1) - Body ground | Always | Below 1 Ω |
Text in Illustration| *a | Rear view of wire harness connector
(to ECM) |
Reconnect the ECM connector.
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 3.CHECK ECM (IGSW VOLTAGE) |
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| G61-14 (IGSW) - C101-14 (E1) | Ignition switch ON | 11 to 14 V |
Text in Illustration| *a | Component with harness connected
(ECM) |
| 4.CHECK ECM (MREL VOLTAGE) |
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| G61-3 (MREL) - C101-14 (E1) | Ignition switch ON | 11 to 14 V |
Text in Illustration| *a | Component with harness connected
(ECM) |
| 5.CHECK NO. 1 INTEGRATION RELAY (EFI) |
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Condition | Specified Condition |
| 1B-4 - Body ground | Ignition switch ON | 10 to 14 V |
Text in Illustration| *a | Rear view of wire harness connector
(to No. 1 Integration Relay) |
Reconnect the No. 1 integration relay (EFI) connector.
| | REPLACE NO. 1 INTEGRATION RELAY (EFI) |
|
|
| 6.CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY (EFI) - ECM AND BODY GROUND) |
Disconnect the No. 1 integration relay (EFI) connector from the engine room junction block.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
| Tester Connection | Condition | Specified Condition |
| 1B-2 - G61-3 (MREL) | Always | Below 1 Ω |
| 1B-4 - G61-12 (+B) | Always | Below 1 Ω |
| 1B-3 - Body ground | Always | Below 1 Ω |
- Standard Resistance (Check for Short):
| Tester Connection | Condition | Specified Condition |
| 1B-2 or G61-3 (MREL) - Body ground | Always | 10 kΩ or higher |
| 1B-4 or G61-12 (+B) - Body ground | Always | 10 kΩ or higher |
Reconnect the No. 1 integration relay (EFI) connector.
Reconnect the ECM connector.
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| OK | |
| |
| REPAIR OR REPLACE HARNESS OR CONNECTOR (TERMINAL +B OF ECM - BATTERY) |
|
| 7.INSPECT IGNITION SWITCH ASSEMBLY |
Inspect the ignition switch assembly (See page ).
| | REPLACE IGNITION SWITCH ASSEMBLY
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| OK | |
| |
| REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGNITION SWITCH, IGNITION SWITCH - ECM) |
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