Toyota Avalon 2007 Wiring Diagram – Factory OEM Specs

Been there. Customer brings in a 2007 Avalon with a no-start that died at a gas station. You pull out a generic wiring schematic from some third-party website. The colors are wrong. The pin numbers don’t match. Now you’re chasing a ghost. That’s why I keep the Toyota Avalon 2007 Wiring Diagram on my bench. This is the factory document—19 pages, no compression, no reprints of something a guy scanned on his home copier. Toyota printed these for their own techs. The wire colors, the connector cavities, the relay locations—all verified at the plant. You trace a circuit on page 1 and you find the problem on the car. Every time.

19 Pages of Factory Wire Routing

Nineteen pages. That’s the whole thing. Not a 500-page manual that buries the diagram under bulletins. The Wiring Diagram gives you the engine control circuits, the ignition switch paths, the fuel pump power feed, and the smart key system interlocks. Page 1 shows the EFI No. 2 circuit with the A/F relay, the EFI relay, and the fuel pump relation. Page 2 covers the ST CUT relay and the ignition switch positions with the smart key and standard key variations. You see exactly where the 7.5A AM1 fuse sits and how the ACC, IG1, and ST1 terminals connect. No guesswork about which wire is the starter signal—it’s drawn right there.

Does This Wiring Diagram Cover the Fuel System?

It does. The fuel pump circuit is on page 1. The EFI No. 2 circuit includes the fuel suction pump and gage assembly. The C/OPN relay controls the pump operation. If you’re diagnosing a no-fuel condition, you trace from the battery through FL MAIN 3.0W, through the EFI relay, down to the pump. The diagram shows the ground paths and the junction connectors. No need to reverse-engineer anything. Toyota put all the splice locations and connector numbers in the margins. I’ve used this to find a corroded ground at junction connector D41 that two other shops missed.

Smart Key System Variations

Two versions exist on this 2007 Avalon: with and without the smart key system. The manual marks them with ∗1 and ∗2. On page 2, you see the ignition switch wiring changes between the two. The smart key system adds an extra control ECU and a different starter relay path. The wire colors shift—for example, the B–W wire with smart key becomes B without it. If you use a generic diagram that ignores these variations, you’ll either blow a fuse or leave a customer stranded. The factory document accounts for both. That’s why I tell guys: pay for the OEM sheet or pay for the tow truck.

3 Reasons to Use OEM Wiring Over Aftermarket

First, the wire colors match. Aftermarket diagrams often use generic color codes like “red/black” when Toyota calls it “L–B”. That half-inch difference can send you to the wrong harness. Second, the connector view numbers tie to actual cavity numbers. Page 3 lists junctions like A41(A), A24(D), B45(A)—those are real connector locations. Third, the component names are Toyota’s own. “Power Source Control ECU” is not the same as “body control module” on a generic chart. The OEM doc keeps you aligned with the parts catalog and the TIS bulletins. If you have to order a connector or a pin, the factory part number is right there in the drawing.

What About the Engine Control Module Connections?

The engine control module (ECM) connections are on page 3. The diagram shows the ECM with terminals STA, STSW, ACCR, FC, +B, +B2, MREL, BATT. Each pin has a wire color and destination. For example, the STA terminal connects to the starter relay via a B wire. The STSW terminal goes to the power source control ECU. The MREL pin feeds the EFI relay. If you’re swapping an ECM or chasing a communication fault, you need these connections verified. The Toyota Avalon 2007 Wiring Diagram gives you the exact pin assignments without any “typical” disclaimers.

FAQ

Is this just a wiring diagram, or does it include diagnostic steps?

It’s a pure wiring diagram. 19 pages of schematics and connector views. No diagnostic flowcharts. But if you know how to read a schematic, this is all you need to trace opens, shorts, and voltage drops.

Does it show the audio or navigation system?

No. This manual covers the engine control, ignition, fuel system, and smart key circuits. The stereo and nav system are not included. You’d need the full electrical wiring diagram manual for those.

How many pages does it have?

19 pages.

Can I use this for a 2008 Avalon?

2008 is a different model year with changes to the smart key system and ECM pinout. This diagram is specifically for the 2007 model. Using it on a 2008 could mislead you on wire colors and connector positions.

Related manuals you might need: Toyota Multi-Model 2001-2014 ECU Flash Reprogramming Manual covers the programming side. For full vehicle repair look at 1999 Toyota Camry RAV4 Avalon ES300 Sienna Repair Manual. If you want the owner’s reference, Toyota Avalon 2005 User Manual – OEM Pocket Reference Guide is a separate item. For more on reading schematics, check out Automotive Wiring. And for Toyota’s official resources, visit Automotive Industry Overview.

You want to stop wasting hours on bad diagrams? Download the Factory Manual. Put it on your tablet or print it out. The next time a 2007 Avalon rolls in with a crank-no-start, you’ll have the exact path from battery to starter on your bench. No translation needed. That’s what factory documentation does. Download the Factory Manual and get back to turning wrenches.