P1606 – Idle Air Control / Rough Idle (Toyota)

Description

The ECM detected improper idle air control operation affecting airflow and idle stability.

Need More Than Just the Fault Code?

A diagnostic scanner with live data, freeze-frame information and the right system access can help you investigate the actual cause before replacing parts.

Compare Diagnostic Scanners

Symptoms

Rough idle
Low idle speed
Engine shaking
Possible stalling
Poor throttle response

Causes

Faulty idle air control valve
Vacuum leaks
Dirty throttle body
Weak ignition components
ECM idle adaptation lost

Diagnosis

Inspect IAC valve
Check vacuum hoses
Clean throttle body
Test ignition coils
Perform idle relearn

Repair

Replace IAC valve
Repair vacuum leaks
Clean throttle body
Replace coils if needed