Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
RELAY CONTROL SYSTEM: System Description
IPDM E/R activates the internal control circuit to perform the relay ON-OFF control according to the input signals from various sensors and the request signals received from control units via CAN communication.
| Control relay | Input/output | Transmit unit | Control part | Reference |
|---|---|---|---|---|
|
|
BCM (CAN) |
|
SYSTEM HEADLAMP SYSTEM: SYSTEM DESCRIPTION - FOR CANADA |
| Tail lamp relay | Position light request signal | BCM (CAN) |
|
PARKING, LICENSE PLATE AND TAIL LAMP SYSTEM: SYSTEM DIAGRAM ILLUMINATION CONTROL SYSTEM |
| Front fog lamp relay | Fog lamp request signal | BCM (CAN) | Front fog lamps | DAYTIME RUNNING LIGHT SYSTEM: SYSTEM DIAGRAM - FOR CANADA |
|
Front wiper request signal | BCM (CAN) | Front wiper motor | SYSTEM |
| Rear window defogger relay | Rear window defogger request signal | BCM (CAN) | Rear window defogger | SYSTEM |
| A/C relay | A/C request signal |
|
A/C compressor | FRONT MANUAL AIR CONDITIONING SYSTEM: AIR INLET CONTROL |
| Starter relay | Ignition switch START signal | TCM | Starter motor | SYSTEM |
| Cooling fan relay 1 Cooling fan relay 2 |
Cooling fan request signal | ECM (CAN) | Cooling fan motor (low) Cooling fan motor (hi) |
CAN COMMUNICATION: SYSTEM DESCRIPTION
(VQ40DE) COAST OPERATION (VK56DE) |
| Heated mirror relay | Heated mirror request signal | BCM (CAN) | Door mirrors | WIRING DIAGRAM |
| ECM relay | ECM relay control signal | ECM (CAN) | ECM | ENGINE CONTROL SYSTEM: SYSTEM DESCRIPTION
(VQ40DE) SYSTEM (VK56DE) |
| Throttle control motor relay | Throttle control motor control signal | ECM (CAN) | ECM | MULTIPORT FUEL INJECTION SYSTEM: SYSTEM DESCRIPTION
(VQ40DE) MULTIPORT FUEL INJECTION SYSTEM: SYSTEM DESCRIPTION (VK56DE) |
| Fuel pump relay | Fuel pump request signal | ECM (CAN) | Fuel pump | MULTIPORT FUEL INJECTION SYSTEM: SYSTEM DESCRIPTION
(VQ40DE) MULTIPORT FUEL INJECTION SYSTEM: SYSTEM DESCRIPTION (VK56DE) |
| Ignition relay | Ignition switch ON or START signal | Ignition switch | Ignition switch ON or START power | FUEL INJECTION TIMING
(VQ40DE) FUEL INJECTION TIMING (VK56DE) |
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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