What causes P1605 on a Honda?

Internal ECM knock processing fault Failing knock sensor feeding noise Engine mechanical noise (worn bearings, piston slap) Corroded knock sensor connector Low system voltage

How do I fix P1605 on a Honda?

Rule out real mechanical noise first Test the knock sensor and sub-harness Verify system voltage stability Check for TSBs on knock logic Replace the ECM only after sensor exclusion

P1605 Knock Control CPU Malfunction (Honda)

Q: What does P1605 mean on a Honda?

P1605 — Knock Control CPU Malfunction (Honda). Applies to Civic, Accord, CR-V.

Category: Powertrain - Ignition
Severity: Check Engine Light
Applies to: Civic, Accord, CR-V

What does P1605 mean on a Honda?

P1605 — Knock Control CPU Malfunction (Honda). This Honda-enhanced code applies to Civic, Accord, CR-V.

Common causes of P1605

Internal ECM knock processing fault
Failing knock sensor feeding noise
Engine mechanical noise (worn bearings, piston slap)
Corroded knock sensor connector
Low system voltage

How to fix P1605

Rule out real mechanical noise first
Test the knock sensor and sub-harness
Verify system voltage stability
Check for TSBs on knock logic
Replace the ECM only after sensor exclusion