P1520: Intake Manifold Runner Control Circuit Malfunction

Definition

The OBD2 code P1520 indicates a malfunction in the intake manifold runner control circuit, which affects the operation of the intake manifold runner control system that optimizes airflow for engine performance

Common causes

Faulty intake manifold runner control (IMRC) actuator
Damaged or frayed wiring in the IMRC circuit
Poor electrical connections or corroded connectors
Malfunctioning IMRC solenoid
Vacuum leaks in the intake system
Faulty engine control module (ECM)
Blocked or stuck intake manifold runner
Faulty throttle position sensor (TPS)

Common misdiagnoses

Faulty intake manifold runner control valve
Vacuum leaks
Throttle body issues
Mass air flow sensor problems
Wiring or connector issues
Engine control module (ECM) failure
Faulty sensors (e.g., MAP or MAF sensors)
Fuel delivery problems
Ignition system issues
Exhaust system restrictions

Troubleshooting steps

1. Check for Additional Codes

Use an OBD-II scanner to check for any other trouble codes that may be present. Addressing all related codes can help in diagnosing the issue more effectively
2. Inspect the Wiring and Connectors
3. Visually inspect the wiring and connectors associated with the IMRC system. Look for signs of damage, corrosion, or loose connections
4. Ensure that the connectors are securely attached and that there are no broken wires
5. Test the IMRC Actuator
6. If accessible, test the IMRC actuator for proper operation. You can do this by applying direct voltage to the actuator to see if it moves as expected
7. If the actuator does not respond, it may need to be replaced
8. Check the IMRC Solenoid
9. If your vehicle has an IMRC solenoid, test it for proper operation. Ensure that it is receiving the correct voltage and that it is functioning as intended
10. Inspect the Intake Manifold
11. Check the intake manifold for any obstructions or damage that could affect the operation of the runners
12. Ensure that the runners are not stuck or clogged
13. Test the Engine Control Module (ECM)
14. If all other components check out, the issue may lie with the ECM. Use a multimeter to test the output signals from the ECM to the IMRC actuator
15. If the ECM is not sending the correct signals, it may need to be reprogrammed or replaced
16. Clear the Codes and Test Drive
17. After performing repairs or replacements, clear the trouble codes using the OBD-II scanner
18. Take the vehicle for a test drive to see if the code returns. Monitor the vehicle's performance to ensure that the issue has been resolved
19. Consult a Professional
20. If you are unable to diagnose or fix the issue after these steps, it may be best to consult a professional mechanic who has experience with your specific vehicle make and model. By following these steps, you should be able to identify and resolve the issue related to the P1520 code

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check for Additional Codes

2. Inspect the Wiring and Connectors

3. Visually inspect the wiring and connectors associated with the IMRC system. Look for signs of damage, corrosion, or loose connections

4. Ensure that the connectors are securely attached and that there are no broken wires

5. Test the IMRC Actuator

6. If accessible, test the IMRC actuator for proper operation. You can do this by applying direct voltage to the actuator to see if it moves as expected

7. If the actuator does not respond, it may need to be replaced

8. Check the IMRC Solenoid

9. If your vehicle has an IMRC solenoid, test it for proper operation. Ensure that it is receiving the correct voltage and that it is functioning as intended

10. Inspect the Intake Manifold

11. Check the intake manifold for any obstructions or damage that could affect the operation of the runners

12. Ensure that the runners are not stuck or clogged

13. Test the Engine Control Module (ECM)

14. If all other components check out, the issue may lie with the ECM. Use a multimeter to test the output signals from the ECM to the IMRC actuator

15. If the ECM is not sending the correct signals, it may need to be reprogrammed or replaced

16. Clear the Codes and Test Drive

17. After performing repairs or replacements, clear the trouble codes using the OBD-II scanner

18. Take the vehicle for a test drive to see if the code returns. Monitor the vehicle's performance to ensure that the issue has been resolved

19. Consult a Professional

20. If you are unable to diagnose or fix the issue after these steps, it may be best to consult a professional mechanic who has experience with your specific vehicle make and model. By following these steps, you should be able to identify and resolve the issue related to the P1520 code