P20F8 — Intake Manifold Runner Control Circuit Performance (Bank 1)
The IMRC actuator drive circuit on bank 1 is electrically OK but its current draw or duty-cycle response is outside the calibrated profile — typically a high-resistance solenoid winding or a partially shorted driver.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Imrc actuator
- Imrc harness
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Solenoid winding ageing — resistance climbing
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Related codes
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.