Intake Manifold Tuning Valve Control Circuit/Open Bank 1
The P0660 code indicates the engine control module has detected a malfunction in the intake manifold tuning valve control circuit for Bank 1, preventing the valve from operating smoothly as commanded. This affects the engine's ability to optimize intake air tuning across different RPM ranges, resulting in degraded performance.
What You Might Notice
- Poor engine performance and reduced power output
- Loud clicking or rattling noise from engine bay
- Decreased fuel economy
- Engine misfire on cold startup
- Difficulty starting in cold weather
Most Common Causes
- 1
Intake Manifold Tuning Valve Malfunction
The tuning valve itself may be stuck, damaged, or worn, preventing it from rotating freely in response to ECM commands. This is the most common cause of this code.
- 2
Wiring or Connector Issues
Corroded, loose, or damaged wiring connections to the tuning valve solenoid can interrupt the control signal from the ECM, causing the circuit to open.
- 3
Solenoid Control Circuit Failure
The solenoid that operates the tuning valve may be electrically defective or have an open circuit, preventing proper valve actuation.
- 4
ECM Programming or Sensor Error
A faulty intake position sensor, engine temperature sensor, or ECM software issue can cause the module to incorrectly command the tuning valve circuit.
How to Diagnose It
- 1
Check Intake Manifold Tuning Valve Malfunction — The tuning valve itself may be stuck, damaged, or worn, preventing it from rotating freely in response to ECM commands. This is the most common cause of this code.
- 2
Check Wiring or Connector Issues — Corroded, loose, or damaged wiring connections to the tuning valve solenoid can interrupt the control signal from the ECM, causing the circuit to open.
- 3
Check Solenoid Control Circuit Failure — The solenoid that operates the tuning valve may be electrically defective or have an open circuit, preventing proper valve actuation.
- 4
Check ECM Programming or Sensor Error — A faulty intake position sensor, engine temperature sensor, or ECM software issue can cause the module to incorrectly command the tuning valve circuit.
How to Fix It
- 1
Inspect and Clean Tuning Valve Assembly
Remove the intake manifold tuning valve and inspect for carbon buildup, rust, or mechanical damage. Clean thoroughly or replace if damaged. Ensure the valve rotates freely without binding.
- 2
Check Wiring and Connectors
Inspect the wiring harness and connector pins to the tuning valve solenoid for corrosion, looseness, or damage. Repair or replace corroded connectors and re-secure loose connections.
- 3
Replace Tuning Valve Solenoid
If the solenoid tests as defective with a multimeter or cannot be cleaned to restore operation, replace the complete tuning valve solenoid assembly with a new OEM or quality aftermarket unit.
- 4
Verify Sensor and ECM Function
Test intake air temperature and engine coolant temperature sensors for proper readings. If sensors are faulty or ECM reprogramming is needed, have a dealer or qualified technician perform diagnostics and updates.
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