P1660: OCC Signal High - Output Control Circuit Malfunction
The P1660 code indicates that the Engine Control Module (ECM) has detected a high voltage signal from the Output Control Circuit (OCC). This circuit is responsible for controlling various engine actuators such as the idle air control valve, EGR valve, or other solenoids. A high signal typically means the circuit voltage is above the expected range, often due to a short to power, faulty actuator, or ECM issue. This can cause drivability problems and may trigger the check engine light.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or stalling
- Poor engine performance
- Increased fuel consumption
2. Most Common Causes
- Faulty power steering pressure (PSP) switch
- Open, short to ground, or short to battery in the PSP circuit wiring
- Damaged, corroded, or loose PSP switch connector
- Low power steering fluid level or air in the system
- Internal leak in the power steering pump or rack
- Faulty PCM (rare)
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all codes and freeze frame data.
Step 2: Visually inspect the OCC circuit wiring and connectors for damage, corrosion, or shorts.
Step 3: Test the actuator resistance and operation per manufacturer specifications.
Step 4: Check for voltage at the actuator connector with key on; compare to expected values.
Step 5: If wiring and actuator are good, test the ECM output signal or replace ECM.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause poor engine performance, stalling, or damage to other components. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost typically ranges from $100 to $300, depending on the cause. Replacing an actuator may cost $50-$150, while wiring repairs or ECM replacement can be higher.
5. Commonly Affected Makes
This is a manufacturer-specific code. The exact manufacturer is not confirmed in our current database.