Headlight & Taillight System:
WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
This system uses the multiplex communication system, so check diagnosis system of the multiplex communication system before you proceed with troubleshooting.
HEADLIGHT AND TAILLIGHT SYSTEM
| Symptom/Suspect Area | See | |
|---|---|---|
| Auto Turn-Off System Does Not Operate When The Driver's Door Is Opened | ||
| Drivers Door Courtesy Switch | STEP 3 - INSPECT DOOR COURTESY SWITCH CONTINUITY | |
| Body ECU | BODY CONTROL SYSTEM | |
| Auto Turn-Off System: Headlight And Taillight Do Not Come On | ||
| Body ECU | BODY CONTROL SYSTEM | |
| Wire Harness | Check Wiring Harness | |
| Auto Turn-Off, System: Headlight And Taillight Stay On. | ||
| Body ECU | BODY CONTROL SYSTEM | |
| Wire Harness | Check Wiring Harness | |
W/O DAYTIME RUNNING LIGHT SYSTEM
| Symptom/Suspect Area | See | |
|---|---|---|
| Only One Headlight Comes On | ||
| Bulb | Check Bulb | |
| Wire Harness | Check Wiring Harness | |
| "Low-Beam" Does Not Light (All) | ||
| Headlight Control Relay | STEP 3 - INSPECT HEADLIGHT CONTROL RELAY CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
| "Low-Beam" Does Not Light (One Side) | ||
| Bulb | Check Bulb | |
| HEAD LH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| HEAD RH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| Wire Harness | Check Wiring Harness | |
| "High-Beam" Does Not Light (All) | ||
| Headlight Dimmer Switch | STEP 2 - INSPECT HEADLIGHT DIMMER SWITCH CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
| "High-Beam" Does Not Light (One Side) | ||
| Bulb | Check Bulb | |
| HEAD LH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| HEAD RH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| Wire Harness | Check Wiring Harness | |
| "Flash" Does Not Light | ||
| Bulb | Check Bulb | |
| HEAD LH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| HEAD RH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| Headlight Dimmer Switch | STEP 2 - INSPECT HEADLIGHT DIMMER SWITCH CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
| "Flash" Does Not Light | ||
| Bulb | Check Bulb | |
| Wire Harness | Check Wiring Harness | |
| Headlight Does Not Come On | ||
| Headlight Control Relay | STEP 3 - INSPECT HEADLIGHT CONTROL RELAY CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
| Headlight Does Not Come On | ||
| Bulb | Check Bulb | |
| Wire Harness | Check Wiring Harness | |
| Headlight Flickers | ||
| Bulb | Check Bulb | |
| Wire Harness | Check Wiring Harness | |
| Headlight Is Dark | ||
| Bulb | Check Bulb | |
| Wire Harness | Check Wiring Harness | |
| Only One Taillight Comes On | ||
| Bulb | Check Bulb | |
| Wire Harness | Check Wiring Harness | |
| Taillight Does Not Come On (Headlight Is Normal) | ||
| Tail Fuse | INSTRUMENT PANEL JUNCTION BLOCK | |
| Tail Relay | STEP 4 - INSPECT TAILLIGHT CONTROL RELAY CONTINUITY | |
| Light Control Switch | STEP 1 - INSPECT LIGHT CONTROL SWITCH CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
| Taillight Does Not Come On (Headlight Does Not Light) | ||
| Light Control Switch | STEP 1 - INSPECT LIGHT CONTROL SWITCH CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
W/DAYTIME RUNNING LIGHT SYSTEM
| Symptom/Suspect Area | See | |
|---|---|---|
| Only One Headlight Comes On | ||
| Daytime Running Light Relay | STEP 5 - INSPECT DRL RELAY CONTINUITY | |
| Daytime Running Light Main Relay | STEP 6 - INSPECT DAYTIME RUNNING LIGHT MAIN RELAY CIRCUIT | |
| Bulb | Check Bulb | |
| Wire Harness | Check Wiring Harness | |
| "Low-Beam" Does Not Light (All) | ||
| Headlight Control Relay | STEP 3 - INSPECT HEADLIGHT CONTROL RELAY CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
| "Low-Beam" Does Not Light (One Side) | ||
| Bulb | Check Bulb | |
| HEAD LO LH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| HEAD LO RH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| Wire Harness | Check Wiring Harness | |
| "High-Beam" Does Not Light (All) | ||
| Headlight Dimmer Switch | STEP 2 - INSPECT HEADLIGHT DIMMER SWITCH CONTINUITY | |
| Daytime Running Light Main Relay | STEP 6 - INSPECT DAYTIME RUNNING LIGHT MAIN RELAY CIRCUIT | |
| Combination Meter | Check Combination Meter | |
| "High-Beam" Does Not Light (One Side) | ||
| Bulb | Check Bulb | |
| HEAD HI LH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| HEAD HI RH Fuse | ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS | |
| Daytime Running Light Relay | STEP 5 - INSPECT DRL RELAY CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
| "Flash" Does Not Light | ||
| Bulb | Check Bulb | |
| Headlight Dimmer Switch | STEP 2 - INSPECT HEADLIGHT DIMMER SWITCH CONTINUITY | |
| Daytime Running Light Main Relay | STEP 6 - INSPECT DAYTIME RUNNING LIGHT MAIN RELAY CIRCUIT | |
| Wire Harness | Check Wiring Harness | |
| Headlight Does Not Come On | ||
| Headlight Control Relay | STEP 3 - INSPECT HEADLIGHT CONTROL RELAY CONTINUITY | |
| Daytime Running Light Main Relay | STEP 6 - INSPECT DAYTIME RUNNING LIGHT MAIN RELAY CIRCUIT | |
| Daytime Running Light Relay | STEP 5 - INSPECT DRL RELAY CONTINUITY | |
| Headlight Dimmer Switch | STEP 2 - INSPECT HEADLIGHT DIMMER SWITCH CONTINUITY | |
| Light Control Switch | STEP 1 - INSPECT LIGHT CONTROL SWITCH CONTINUITY | |
| Body ECU | BODY CONTROL SYSTEM | |
| Wire Harness | Check Wiring Harness | |
| Bulb | Check Bulb | |
| Headlight Does Not Come On With Light Control Switch In Head | ||
| Light Control Switch | STEP 1 - INSPECT LIGHT CONTROL SWITCH CONTINUITY | |
| Body ECU | BODY CONTROL SYSTEM | |
| Wire Harness | Check Wiring Harness | |
| Headlight Does Not Come On With Light Control Switch In Off | ||
| Headlight Control Relay | STEP 3 - INSPECT HEADLIGHT CONTROL RELAY CONTINUITY | |
| Body ECU | BODY CONTROL SYSTEM | |
| Wire Harness | Check Wiring Harness | |
| Headlight Flickers | ||
| Bulb | Check Bulb | |
| Wire Harness | Check Wiring Harness | |
| Headlight Is Dark | ||
| Bulb | Check Bulb | |
| Wire Harness | Check Wiring Harness | |
| Taillight Does Not Come On With Light Control Switch In Tail | ||
| Taillight Control Relay | STEP 4 - INSPECT TAILLIGHT CONTROL RELAY CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
| Taillight Does Not Go Out With Light Control Switch In Off | ||
| Taillight Control Relay | STEP 4 - INSPECT TAILLIGHT CONTROL RELAY CONTINUITY | |
| Wire Harness | Check Wiring Harness | |
| Headlight Does Not Come On With Engine Running And Light Control Switch In Off | ||
| ECU-B Fuse | INSTRUMENT PANEL JUNCTION BLOCK | |
| Gauge Fuse | INSTRUMENT PANEL JUNCTION BLOCK | |
| Daytime Running Light Main Relay | STEP 6 - INSPECT DAYTIME RUNNING LIGHT MAIN RELAY CIRCUIT | |
| Daytime Running Light Relay | STEP 5 - INSPECT DRL RELAY CONTINUITY | |
| Alternator L Terminal | Check Alternator Terminals | |
| Body ECU | BODY CONTROL SYSTEM | |
| Parking Brake Switch | STEP 12 - INSPECT PARKING BRAKE SWITCH CONTINUITY | |
| Wire Harness | Check Wiring Harness | |