P1568 IMCC Circuit Malfunction
The P1568 code indicates a fault in the Intake Manifold Charge Control (IMCC) circuit, a system specific to Mazda engines. This system uses a throttle valve in the intake manifold to optimize airflow and cylinder filling across different RPM ranges. The powertrain control module (PCM) detects an electrical or mechanical anomaly in the circuit that operates this valve, such as voltage outside the expected range or a failure in actuator position.
01. Most Common Causes
- Damaged or stuck IMCC actuator (intake manifold valve)
- Corroded or bent pins in the IMCC actuator connector
- Short or open circuit in the IMCC wiring harness
- Blocked air passages or vacuum lines (if applicable to the design)
- Faulty PCM (less common)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or hesitation
- Poor fuel economy
- Rough idle or stalling
03. Step-by-Step Diagnosis
Scan for codes and verify P1568 is present
Visually inspect the IMCC actuator connector and wiring for damage or corrosion
Test the IMCC actuator resistance and operation using a multimeter and scan tool
Check for vacuum leaks or blocked intake passages
If all else is normal, test PCM output signals or replace PCM as last resort
1. Frequently Asked Questions
Is it safe to drive?▼
You can usually drive short distances, but reduced performance and fuel economy may occur. Prolonged driving could lead to further issues, so it's best to diagnose and repair promptly.
How much does it cost to fix?▼
Repair costs typically range from $150 to $500, depending on whether the actuator needs replacement ($100-$300) plus labor and diagnostics.