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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSTOYOTA2012COROLLA BASE, AUTOMATIC TRANSREPAIR AND DIAGNOSISELECTRICALFUSES & CIRCUIT BREAKERSOEM JUNCTION BLOCK, ECU & FUSE/RELAY LOCATIONSRELAY BLOCK IDENTIFICATIONENGINE ROOM RELAY BLOCK ENGINE COMPARTMENT LEFT AND ENGINE ROOM JUNCTION BLOCK
2012 Toyota Corolla Base, Automatic Trans
Engine Room Relay Block Engine Compartment Left And Engine Room Junction Block
2012 Toyota Corolla Base, Automatic TransSECTION Engine Room Relay Block Engine Compartment Left And Engine Room Junction Block
Engine Compartment Left (See Figure)
Engine Room R/B And J/B Relay Identification
| RELAY DESCRIPTION |
|---|
| Fan No. 1 Relay |
| Fan No. 2 Relay |
| Fan No. 3 Relay |
| HTR SUB No. 1 Relay |
| HTR SUB No. 3 Relay |
| Dimmer Relay |
| H-LP Relay |
Engine Room R/B and J/B Fuse Identification Legend
| Fuse | System | |
|---|---|---|
| 7.5A | ALT-S | Charging (Except TMC Made) |
| Charging (TMC Made) | ||
| 7.5A | AM2 NO. 2 | Door Lock Control (Except TMC Made) |
| Engine Control (2ZR-FE) (Except TMC Made) | ||
| Engine Control (TMC Made) | ||
| Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) | ||
| Ignition (Except TMC Made) | ||
| Ignition (TMC Made) | ||
| Interior Light (Except TMC Made) | ||
| Light Reminder (Except TMC Made) | ||
| Power Window (Except TMC Made) | ||
| Sliding Roof (Except TMC Made) | ||
| Starting (TMC Made) | ||
| Starting (w/o Smart Key System) (Except TMC Made) | ||
| 7.5A | IG2 NO. 2 | Engine Control (2AZ-FE) (Except TMC Made) |
| Ignition (Except TMC Made) | ||
| 10A | DOME | Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) |
| Interior Light (Except TMC Made) | ||
| Interior Light (TMC Made) | ||
| Theft Deterrent (Except TMC Made) | ||
| Wireless Door Lock Control (TMC Made) | ||
| Wireless Door Lock Control (w/o Smart Key System) (Except TMC Made) | ||
| 10A | ECU-B | ABS (w/ VSC), TRAC and VSC (Except TMC Made) |
| ABS (w/o VSC) (Except TMC Made) | ||
| ABS, TRAC and VSC (TMC Made) | ||
| Audio System and Navigation System (Except TMC Made) | ||
| Audio System and Navigation System (TMC Made) | ||
| Automatic Air Conditioning (Except TMC Made) | ||
| Automatic Air Conditioning (TMC Made) | ||
| Charging (Except TMC Made) | ||
| Charging (TMC Made) | ||
| Clock (Except TMC Made) | ||
| Clock (TMC Made) | ||
| Combination Meter (Except TMC Made) | ||
| Combination Meter (TMC Made) | ||
| Cruise Control (2AZ-FE) (Except TMC Made) | ||
| Cruise Control (2ZR-FE) (Except TMC Made) | ||
| Cruise Control (TMC Made) | ||
| Door Lock Control (Except TMC Made) | ||
| Door Lock Control (TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (2AZ-FE) (Except TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (2ZR-FE) (Except TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (TMC Made) | ||
| Engine Control (2AZ-FE) (Except TMC Made) | ||
| Engine Control (2ZR-FE) (Except TMC Made) | ||
| Engine Control (TMC Made) | ||
| Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) | ||
| EPS (Except TMC Made) | ||
| EPS (TMC Made) | ||
| Headlight (Except TMC Made) | ||
| Headlight (w/ Daytime Running Light) (TMC Made) | ||
| Illumination and Taillight (Except TMC Made) | ||
| Illumination and Taillight (TMC Made) | ||
| Interior Light (Except TMC Made) | ||
| Interior Light (TMC Made) | ||
| Key Reminder (TMC Made) | ||
| Key Reminder (w/o Smart Key System) (Except TMC Made) | ||
| Light Reminder (Except TMC Made) | ||
| Light Reminder (TMC Made) | ||
| Power Window (Except TMC Made) | ||
| Power Window (TMC Made) | ||
| Seat Belt Warning (Except TMC Made) | ||
| Seat Belt Warning (TMC Made) | ||
| Sliding Roof (Except TMC Made) | ||
| SRS (Except TMC Made) | ||
| SRS (TMC Made) | ||
| Starting (TMC Made) | ||
| Starting (w/o Smart Key System) (Except TMC Made) | ||
| Theft Deterrent (Except TMC Made) | ||
| Tire Pressure Warning System (Except TMC Made) | ||
| Tire Pressure Warning System (TMC Made) | ||
| Wireless Door Lock Control (TMC Made) | ||
| Wireless Door Lock Control (w/o Smart Key System) (Except TMC Made) | ||
| 10A | ECU-B2 | Automatic Air Conditioning (Except TMC Made) |
| Automatic Air Conditioning (TMC Made) | ||
| Engine Immobiliser System (TMC Made) | ||
| Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) | ||
| Engine Immobiliser System (w/o Smart Key System) (Except TMC Made) | ||
| Manual Air Conditioning (Except TMC Made) | ||
| Manual Air Conditioning (TMC Made) | ||
| 10A | EFI NO. 1 | Cruise Control (2AZ-FE) (Except TMC Made) |
| Cruise Control (2ZR-FE) (Except TMC Made) | ||
| Cruise Control (TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (2AZ-FE) (Except TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (2ZR-FE) (Except TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (TMC Made) | ||
| Engine Control (2AZ-FE) (Except TMC Made) | ||
| Engine Control (2ZR-FE) (Except TMC Made) | ||
| Engine Control (TMC Made) | ||
| 10A | EFI NO. 2 | Engine Control (2AZ-FE) (Except TMC Made) |
| Engine Control (2ZR-FE) (Except TMC Made) | ||
| Engine Control (TMC Made) | ||
| 10A | ETCS | Cruise Control (2AZ-FE) (Except TMC Made) |
| Cruise Control (2ZR-FE) (Except TMC Made) | ||
| Cruise Control (TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (2AZ-FE) (Except TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (2ZR-FE) (Except TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (TMC Made) | ||
| Engine Control (2AZ-FE) (Except TMC Made) | ||
| Engine Control (2ZR-FE) (Except TMC Made) | ||
| Engine Control (TMC Made) | ||
| 10A | H-LP LH HI | Headlight (Except TMC Made) |
| Headlight (w/ Daytime Running Light) (TMC Made) | ||
| Headlight (w/o Daytime Running Light) (TMC Made) | ||
| 10A | H-LP LH LO | Headlight (Except TMC Made) |
| Headlight (w/ Daytime Running Light) (TMC Made) | ||
| Headlight (w/o Daytime Running Light) (TMC Made) | ||
| 10A | H-LP RH HI | Headlight (Except TMC Made) |
| Headlight (w/ Daytime Running Light) (TMC Made) | ||
| Headlight (w/o Daytime Running Light) (TMC Made) | ||
| 10A | H-LP RH LO | Headlight (Except TMC Made) |
| Headlight (w/ Daytime Running Light) (TMC Made) | ||
| Headlight (w/o Daytime Running Light) (TMC Made) | ||
| 10A | HORN | Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) |
| Horn (Except TMC Made) | ||
| Horn (TMC Made) | ||
| Theft Deterrent (Except TMC Made) | ||
| Wireless Door Lock Control (TMC Made) | ||
| Wireless Door Lock Control (w/o Smart Key System) (Except TMC Made) | ||
| 10A | TURN-HAZ | Turn Signal and Hazard Warning Light (Except TMC Made) |
| Turn Signal and Hazard Warning Light (TMC Made) | ||
| 15A | IG2 | Engine Control (2AZ-FE) (Except TMC Made) |
| Engine Control (2ZR-FE) (Except TMC Made) | ||
| Engine Control (TMC Made) | ||
| Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) | ||
| Ignition (Except TMC Made) | ||
| Ignition (TMC Made) | ||
| 15A | RAD NO. 1 | Audio System and Navigation System (Except TMC Made) |
| Audio System and Navigation System (TMC Made) | ||
| 20A | EFI MAIN | Cruise Control (2AZ-FE) (Except TMC Made) |
| Cruise Control (2ZR-FE) (Except TMC Made) | ||
| Cruise Control (TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (2AZ-FE) (Except TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (2ZR-FE) (Except TMC Made) | ||
| Electronically Controlled Transmission and A/T Indicator (TMC Made) | ||
| Engine Control (2AZ-FE) (Except TMC Made) | ||
| Engine Control (2ZR-FE) (Except TMC Made) | ||
| Engine Control (TMC Made) | ||
| 20A | STRG LOCK | Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) |
| 30A | ABS NO. 3 | ABS (w/ VSC), TRAC and VSC (Except TMC Made) |
| ABS (w/o VSC) (Except TMC Made) | ||
| ABS, TRAC and VSC (TMC Made) | ||
| 30A | AM2 | Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) |
| Ignition (Except TMC Made) | ||
| Starting (TMC Made) | ||
| Starting (w/o Smart Key System) (Except TMC Made) | ||
| 30A | CDS FAN | Cooling Fan (2AZ-FE) (Except TMC Made) |
| 30A | HTR SUB NO. 1 | Automatic Air Conditioning (Except TMC Made) |
| Automatic Air Conditioning (TMC Made) | ||
| Manual Air Conditioning (Except TMC Made) | ||
| Manual Air Conditioning (TMC Made) | ||
| 30A | HTR SUB NO. 3 | Automatic Air Conditioning (Except TMC Made) |
| Automatic Air Conditioning (TMC Made) | ||
| Manual Air Conditioning (Except TMC Made) | ||
| Manual Air Conditioning (TMC Made) | ||
| 40A | RDI FAN | Cooling Fan (2AZ-FE) (Except TMC Made) |
| Cooling Fan (2ZR-FE) (Except TMC Made) | ||
| Cooling Fan (TMC Made) | ||
| 50A | ABS NO. 1 | ABS (w/ VSC), TRAC and VSC (Except TMC Made) |
| ABS (w/o VSC) (Except TMC Made) | ||
| ABS, TRAC and VSC (TMC Made) | ||
| 50A | H-LP MAIN | Automatic Air Conditioning (Except TMC Made) |
| Automatic Air Conditioning (TMC Made) | ||
| Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) | ||
| Front Fog Light (Except TMC Made) | ||
| Front Fog Light (w/ Daytime Running Light) (TMC Made) | ||
| Headlight (Except TMC Made) | ||
| Headlight (w/ Daytime Running Light) (TMC Made) | ||
| Headlight (w/o Daytime Running Light) (TMC Made) | ||
| Manual Air Conditioning (Except TMC Made) | ||
| Manual Air Conditioning (TMC Made) | ||
| Theft Deterrent (Except TMC Made) | ||
| Wireless Door Lock Control (TMC Made) | ||
| Wireless Door Lock Control (w/o Smart Key System) (Except TMC Made) | ||
| 50A | HTR | Automatic Air Conditioning (Except TMC Made) |
| Automatic Air Conditioning (TMC Made) | ||
| Manual Air Conditioning (Except TMC Made) | ||
| Manual Air Conditioning (TMC Made) | ||
| 60A | EPS | EPS (Except TMC Made) |
| EPS (TMC Made) | ||
| 120A | ALT | Charging (Except TMC Made) |
| Charging (TMC Made) | ||
| Engine Control (2AZ-FE) (Except TMC Made) | ||
| Engine Control (2ZR-FE) (Except TMC Made) | ||
| Engine Control (TMC Made) | ||
| Engine Immobiliser System (w/ Smart Key System), Smart Key System, Starting (w/ Smart Key System), Steering Lock (w/ Smart Key System) and Wireless Door Lock Control (w/ Smart Key System) (Except TMC Made) | ||
| Front Fog Light (w/o Daytime Running Light) (TMC Made) | ||
| Illumination and Taillight (Except TMC Made) | ||
| Illumination and Taillight (TMC Made) | ||
| Light Reminder (Except TMC Made) | ||
| Light Reminder (TMC Made) | ||
| Power Window (Except TMC Made) | ||
| Power Window (TMC Made) | ||
| Sliding Roof (Except TMC Made) | ||
| Theft Deterrent (Except TMC Made) | ||
Engine Compartment Left (See Figure)
Engine Room R/B & J/B Fuse Identification Legend
| For fuse identification see Engine Room R/B and J/B Fuse Identification Legend |
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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.