What does it mean?
P1511 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Differentiated Intake Manifold Control Circuit Electrical .
Symptoms
- Check engine light on with no rough running at idle
- Noticeable loss of pull either at low rpm or in the mid range, depending on the position the flap is stuck in
- Flat spot during acceleration where the manifold should change over
- Slightly higher fuel consumption in mixed driving
- Intake note stays the same through the rev range instead of changing at the switch point
- Engine otherwise starts and idles normally
Likely causes
- Open or shorted control circuit to the manifold flap solenoid or motor
- Corroded terminals in the actuator connector, which sits in a hot area on top of the engine
- Failed actuator coil or motor winding
- Blown fuse or a bad relay contact in the actuator supply
- Harness insulation hardened and cracked by underbonnet heat
- Failed module output driver as the last possibility
How to fix it
- Command the actuator with a scan tool and watch or feel for the flap moving through its travel
- Check the supply fuse and measure voltage and ground at the actuator connector
- Measure the coil or motor resistance and compare it with the specification
- Check the control wire for continuity and for a short to ground or to positive
- Inspect the connector and harness for heat damage, cracked insulation and corroded pins
- Repair the harness, or replace the actuator if it is electrically faulty
- Confirm the flap linkage is free and repeat the actuation test after the repair