P264C: Rocker Arm Actuator Position Sensor Circuit Low Bank 1
The P264C code indicates that the Engine Control Module (ECM) has detected a low voltage signal from the rocker arm actuator position sensor on Bank 1. This sensor monitors the position of the rocker arm actuator, which controls variable valve timing or cylinder deactivation. A low circuit condition typically means the signal voltage is below the expected range, often due to a short to ground, faulty sensor, or wiring issues. This can affect engine performance, fuel economy, and emissions.
1. Most Common Causes
- Faulty or worn VTEC rocker arm actuator (internal oil leak)
- Sensor wiring shorted to ground
- Corroded, oxidized, or damaged sensor connector pins
- Excessive resistance in sensor circuit (loose connection or deteriorated wire)
- Low engine oil level or poor/deteriorated oil quality
- Blocked oil passages in the VTEC system
- Internal ECM/PCM failure (less common)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or performance
- Rough idle or misfire
- Decreased fuel economy
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes.
Step 2: Visually inspect the sensor and wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's voltage and ground circuits with a multimeter; compare to manufacturer specs.
Step 4: If wiring is intact, replace the rocker arm actuator position sensor.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause engine performance issues and potential damage. Limp mode may activate, reducing speed.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the vehicle and shop rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.