Diagnostics

Monitor description

~1min read

The battery supplies electricity to the ecm even when the ignition switch is off. This electricity allows the ecm store data such as dtc history, freeze frame data, fuel trim values, and other data. If the battery voltage falls below a minimum level, the ecm will conclude that there is a fault in the power supply circuit. At the next engine start, the ecm will turn on the mil and a dtc will be set.

Toyota Corolla. Monitor description
Monitor strategy
Toyota Corolla. Monitor strategy

*1: The dtc is set immediately. The mil will be illuminated after the next engine start.

Typical enabling conditions
Toyota Corolla. Typical enabling conditions
Typical malfunction thresholds
Toyota Corolla. Typical malfunction thresholds
Wiring diagram
Toyota Corolla. Wiring diagram

Test yourself

A quick Toyota Corolla quiz: every answer comes with an explanation and a link to the manual page.