Owner's book · not a shop

Know the car. Then the window. Factory specs in plain English — don't authorize until you can say this at the counter.

Owner tools

Lab desks

No dongle required

Type the code

Any $20 scanner. Five characters. We write what it means and what to ask before parts. iPhone Safari has no Web Bluetooth — type the code.

Park first · Mode 03

ELM327

Checking whether this browser can open Web Bluetooth.

U0100

urgent · typical $80–$1,400

The network cannot hear the engine computer. Power, grounds, or a dead ECM — start at fuses.

Usual first look · ECM power/grounds, CAN, ECM

Ask for voltage at the ECM power pins and whether other modules are also silent.

Say this
I have U0100 stored. I want voltage at the ECM power pins before a computer.

Not a driveway parts-cannon — pay for the test

SAE layout: network (modules talking to each other). Subsystem looks like module communication. Generic (SAE) code.

This is an SAE-generic layout. The number is real even if our dictionary has no paragraph yet.

Paste the RO. Circle the line they hung on this pointer. The code is not a parts list.