What causes P1600 on a Toyota?

Blown ECM BATT fuse Recent battery disconnect clearing adaptations Corroded battery terminals Open backup power wire to the ECM Failing ECM memory circuit

How do I fix P1600 on a Toyota?

Check the ECM BATT fuse. Separate from main ECM power Inspect battery cables and grounds Verify backup voltage at the ECM pin Confirm adaptations relearn after a drive cycle Repair the backup feed rather than replacing the ECM first

P1600 ECM Battery Backup (BATT) Malfunction

Q: What does P1600 mean on a Toyota?

P1600. ECM Battery Backup (BATT) Malfunction. Applies to Camry, Corolla, RAV4, Tacoma (all OBD-II Toyotas).

Category: Powertrain - Computer and Auxiliary Controls
Severity: Check Engine Light
Applies to: Camry, Corolla, RAV4, Tacoma (all OBD-II Toyotas)

What does P1600 mean on a Toyota?

P1600. ECM Battery Backup (BATT) Malfunction. This Toyota-enhanced code applies to Camry, Corolla, RAV4, Tacoma (all OBD-II Toyotas).

Common causes of P1600

Blown ECM BATT fuse
Recent battery disconnect clearing adaptations
Corroded battery terminals
Open backup power wire to the ECM
Failing ECM memory circuit

How to fix P1600

Check the ECM BATT fuse. Separate from main ECM power
Inspect battery cables and grounds
Verify backup voltage at the ECM pin
Confirm adaptations relearn after a drive cycle
Repair the backup feed rather than replacing the ECM first

Sources and review

Last updated 2026-09-20.