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DTC 09: ER20

id0902f6818500

DTC 09: Er20 | Power supply circuit of base unit
DETECTION CONDITION | • When the voltage at terminals 1B and 1R is 8.5 V or less, or 16 V or more.
POSSIBLE CAUSE | • Battery malfunction • Power supply wiring harness malfunction

Diagnostic procedure

Step | Inspection | Action
--- | --- | ---
1 | INSPECT FUSE • Remove the ROOM 15 A fuse and MIRROR 7.5 A fuse. • Is the fuse normal? | Yes | Go to the next step.
No | Replace the fuse.
2 | INSPECT BATTERY • Measure battery voltage. • Is voltage 8.5 V-16 V? | Yes | Go to the next step.
No | Battery malfunction Inspect the charge/discharge system.
3 | INSPECT WIRING HARNESS BETWEEN BATTERY AND FUSE BLOCK • Turn the ignition switch to the ACC or ON position. • Measure voltage at fuse block terminals AG and AH. • Is voltage 8.5 V-16 V? | Yes | Go to the next step.
No | Repair the wiring harness between the battery and fuse block.
4 | INSPECT WIRING HARNESS BETWEEN FUSE BLOCK AND BASE UNIT • Turn the ignition switch to the LOCK position. • Install the ROOM 15 A fuse and MIRROR 7.5 A fuse. • Turn the ignition switch to the ACC position. • Measure voltage at the audio unit connector terminal 1B and 1R. • Is voltage 8.5 V-16 V? | Yes | Go to the next step.
No | Repair the wiring harness between the fuse block connector and base unit.
5 | INSPECT BASE UNIT • Turn the ignition switch to the ACC or ON position and hold for 30 s or more. • DTC 09: Er20 displayed? | Yes | Replace the base unit.
No | Troubleshooting completed.