Description

IG1 relay circuit malfunction

Detection condition

• Start stop unit detects the IG1 monitor voltage of less than 2.5 V for 1 s or more while the engine is not being cranked with the ignition switched ON (engine off or on).

Fail-safe

Not applicable

Possible cause

• IG1 relay malfunction

• IG1 relay circuit malfunction

• Short to ground in wiring harness between MAIN 200 A fuse and IG1 relay terminal D

• MAIN 200 A fuse malfunction

• Open circuit in wiring harness between battery positive terminal and IG1 relay terminal D

• Start stop unit connector or terminal malfunction

• Wiring harness between IG1 relay terminal C and start stop unit terminal 1B malfunction

• Short to ground in wiring harness between IG1 relay terminal C and start stop unit terminal 1B

• C/U IG1 15 A fuse malfunction

• Wiring harness between IG1 relay terminal C and start stop unit terminal 1B malfunction

• C/U IG1 15 A fuse malfunction

• Open circuit in wiring harness between IG1 relay terminal C and start stop unit terminal 1B

• Start stop unit malfunction

Step

Inspection

Action

1

• Switch the ignition off.

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Remove the IG1 relay.

  (See RELAY LOCATION.)

• Inspect the IG1 relay.

  (See RELAY INSPECTION.)

• Is the IG1 relay normal?

Yes

Go to the next step.

No

Replace the IG1 relay, then go to Step 6.

(See RELAY LOCATION.)

2

• Verify that the IG1 relay is removed.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Measure the voltage at the IG1 relay terminal D (wiring harness-side).

• Is the voltage B+?

Yes

Go to the next step.

No

Inspect the MAIN 200 A fuse.

• If the fuse is blown:

• Refer to the wiring diagram and verify whether or not there is a common connector between MAIN 200 A fuse and IG1 relay terminal D.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has a short to ground.

• Replace the fuse.

• If the fuse is damaged:

• Replace the fuse.

• If the fuse is normal:

• Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and IG1 relay terminal D.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has an open circuit.

Go to Step 6.

3

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Disconnect the start stop unit connector.

• Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection.

• Is the connector normal?

Yes

Go to the next step.

No

Repair or replace the connector, then go to Step 6.

4

• Verify that the IG1 relay is removed.

• Verify that the start stop unit connector is disconnected.

• Inspect for continuity between the following terminals (wiring harness-side) and body ground:

• IG1 relay terminal C

• Start stop unit terminal 1B

• Is there continuity?

Yes

Inspect the C/U IG1 15 A fuse.

• If the fuse is blown:

• Refer to the wiring diagram and verify whether or not there is a common connector between C/U IG1 15 A fuse and start stop unit terminal 1B.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has a short to ground.

• Replace the fuse.

• If the fuse is damaged:

• Replace the fuse.

• If the fuse is normal:

• Refer to the wiring diagram and verify whether or not there is a common connector between IG1 relay terminal C and C/U IG1 15 A fuse.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has a short to ground.

Go to Step 6.

No

Go to the next step.

5

• Verify that the IG1 relay is removed.

• Verify that the start stop unit connector is disconnected.

• Inspect for continuity between IG1 relay terminal C (wiring harness-side) and start stop unit terminal 1B (wiring harness-side).

• Is there continuity?

Yes

Go to the next step.

No

Inspect the C/U IG1 15 A fuse.

• If the fuse is damaged:

• Replace the fuse.

• If the fuse is normal:

• Refer to the wiring diagram and verify whether or not there is a common connector between IG1 relay terminal C and start stop unit terminal 1B.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has an open circuit.

Go to the next step.

6

• Always reconnect all disconnected connectors.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Clear the DTC for the start stop unit using the M-MDS.

  (See CLEARING DTC [START STOP UNIT].)

• Switch the ignition ON (engine off or on) and wait for 1 s or more.

• Retrieve the start stop unit DTCs using the M-MDS.

  (See DTC INSPECTION [START STOP UNIT].)

• Is the same DTC displayed?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the start stop unit.

  (See START STOP UNIT REMOVAL/INSTALLATION.)

Go to the next step.

No

Go to the next step.

7

• Are any other DTCs displayed?

Yes

Repair or replace the malfunctioning part according to the applicable DTC troubleshooting.

(See DTC TABLE [START STOP UNIT].)

No

DTC troubleshooting completed.