SFI SYSTEM > ECM Power Source Circuit |
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DESCRIPTION
When the ignition switch is turned to the ON position, the battery voltage is applied to terminal IGSW of the ECM. The ECM MREL output signal causes a current to flow to the coil, closing the contacts of the EFI relay and supplying power to terminal +B of the ECM.If the ignition switch is turned off, the ECM holds the EFI relay ON for a maximum of 2 seconds to allow for the initial setting of the throttle valve.
When the ignition switch is turned to the ON position, voltage from the ECM's MREL terminal is applied to the engine room junction block (EFI relay). This causes the contacts of the engine room junction block (EFI relay) to close, which supplies power to terminal +B or +B2 of the ECM.
WIRING DIAGRAM
INSPECTION PROCEDURE
1.CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) |
Disconnect the C58 (RHD) or C55 (LHD) ECM connector.
Measure the resistance between the terminals.
- Standard resistance:
- RHD:
Tester Connection Specified Condition E1 (C58-81) - Body ground Below 1 Ω - LHD:
Tester Connection Specified Condition E1 (C55-81) - Body ground Below 1 Ω
Reconnect the ECM connector.
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OK | |
2.CHECK ENGINE ROOM JUNCTION BLOCK (EFI RELAY VOLTAGE) |
Remove the engine room junction block from the engine room R/B.
Turn the ignition switch to the ON position.
Measure the voltage between the terminals.
- Standard voltage:
Tester Connection Specified Condition 1E-6 - Body ground 9 to 14 V
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NG | |
3.INSPECT EFI MAIN FUSE |
Remove the EFI MAIN fuse from the engine room R/B.
Measure the EFI MAIN fuse resistance.
- Standard resistance:
- Below 1 Ω
Reinstall the EFI MAIN fuse.
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OK | |
Go to step 6 |
4.CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK - BATTERY) |
Disconnect the negative battery terminal.
Disconnect the positive battery terminal.
Remove the engine room junction block from the engine room R/B.
Measure the resistance between the terminals.
- Standard resistance:
- Check for open:
Tester Connection Specified Condition 1G-1 - Positive battery terminal Below 1 Ω - Check for short:
Tester Connection Specified Condition 1G-1 or Positive battery terminal - Body ground 10 kΩ or higher
Reinstall the engine room junction block.
Reconnect the positive battery terminal.
Reconnect the negative battery terminal.
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OK | ||
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5.INSPECT ENGINE ROOM JUNCTION BLOCK (EFI RELAY) |
Remove the engine room junction block from the engine room R/B.
Measure the resistance between the terminals.
- Standard resistance:
Tester Connection Specified Condition 1E-6 - 1E-12 10 kΩ or higher 1E-6 - 1E-12 Below 1 Ω
(Apply battery voltage between terminals 1E-9 and 1E-11)
Reinstall the engine room junction block.
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OK | |
6.INSPECT EFI NO. 2 FUSE |
Remove the EFI No. 2 fuse from the engine room R/B.
Measure the EFI No. 2 fuse resistance.
- Standard resistance:
- Below 1 Ω
Reinstall the EFI No. 2 fuse.
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OK | |
7.CHECK HARNESS AND CONNECTOR (ECM - ENGINE ROOM JUNCTION BLOCK) |
Disconnect the A24 (RHD) or A55 (LHD) ECM connector.
Remove the engine room junction block from the engine room R/B.
Measure the resistance between the terminals.
- Standard resistance (Check for open):
- RHD:
Tester Connection Specified Condition 1E-6 - +B (A24-2) Below 1 Ω 1E-6 - +B2 (A24-1) Below 1 Ω - LHD:
Tester Connection Specified Condition 1E-6 - +B (A55-2) Below 1 Ω 1E-6 - +B2 (A55-1) Below 1 Ω
- Standard resistance (Check for open):
- RHD:
Tester Connection Specified Condition 1E-6 or +B (A24-2) - Body ground 10 kΩ or higher 1E-6 or +B2 (A24-1) - Body ground 10 kΩ or higher - LHD:
Tester Connection Specified Condition 1E-6 or +B (A55-2) - Body ground 10 kΩ or higher 1E-6 or +B2 (A55-1) - Body ground 10 kΩ or higher
Reinstall the engine room junction block.
Reconnect the ECM connector.
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OK | |
8.INSPECT ECM (IGSW VOLTAGE) |
Disconnect the A24 (RHD) or A55 (LHD) ECM connector.
Measure the voltage between the terminals.
- Standard voltage:
- RHD:
Tester Connection Specified Condition IGSW (A24-28) - Body ground 9 to 14 V - LHD:
Tester Connection Specified Condition IGSW (A55-28) - Body ground 9 to 14 V
Reconnect the ECM connector.
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NG | |
9.INSPECT IGNITION RELAY NO. 2 |
Remove the IG2 relay from the engine room R/B.
Measure the resistance between the terminals.
- Standard resistance:
Tester Connection Specified Condition 3 - 5 10 kΩ or higher 3 - 5 Below 1 Ω
(Apply battery voltage between terminals 1 and 2)
Reinstall the IG2 relay.
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OK | |
10.CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND) |
Remove the IG2 relay from the engine room R/B.
Measure the resistance between the terminals.
- Standard resistance:
Tester Connection Specified Condition IG2 relay terminal 2 - Body ground Below 1 Ω
Reinstall the IG2 relay.
- Result:
Result Proceed to OK A NG B
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A | |
11.INSPECT IGNITION SWITCH ASSEMBLY |
Disconnect the E23 ignition switch connector.
Measure the resistance between the terminals.
- Standard resistance:
Tester Connection Ignition Switch Position Specified Condition All terminals LOCK 10 kΩ or higher 2 - 4 ACC Below 1 Ω 1 - 2 - 4, 5 - 6 ON 1 - 3 - 4, 5 - 6 - 7 START
Reconnect the ignition switch connector.
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OK | ||
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12.CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) |
Disconnect the A24 (RHD) or A55 (LHD) ECM connector.
Measure the resistance between the terminals.
- Standard resistance:
- RHD:
Tester Connection Specified Condition MREL (A24-24) - Body ground Below 1 Ω - LHD:
Tester Connection Specified Condition MREL (A55-24) - Body ground Below 1 Ω
Reconnect the ECM connector.
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OK | ||
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