P1106
FordDual Alternator Lower Fault/ Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent High Voltage
Medium SeverityThis code indicates an issue with either the Manifold Absolute Pressure (MAP) sensor circuit reporting an intermittently high voltage, or a fault in the lower section of a dual alternator system. This can lead to various engine performance problems like rough idle or poor fuel economy, or electrical system issues if the alternator is failing.
⚠️ Before You Begin (Safety First)
Always ensure your vehicle is parked safely on level ground with the parking brake engaged before performing any work. Disconnect the negative battery terminal before working on electrical components to prevent accidental shorts or shocks. Allow the engine to cool completely before touching any engine components.
Common Symptoms
- Check Engine Light illuminated
- Reduced engine performance
- Poor fuel economy
- Rough idle or stalling
- Difficulty starting (if alternator related)
- Battery warning light (if alternator related)
Common Causes
- Faulty MAP sensor
- Damaged or corroded wiring/connector to the MAP sensor
- Short to voltage in the MAP sensor circuit
- Malfunctioning Engine Control Module (ECM) or Powertrain Control Module (PCM)
- Faulty lower alternator in a dual alternator system
- Wiring issues in the dual alternator system
Frequently reported on: Ford F-150 (2004-2010), Ford Expedition (2003-2014), Ford F-250 Super Duty (2000-2016), Ford Explorer (2002-2010)
Diagnostic Steps
- Inspect the MAP sensor and its electrical connector for any visible damage, corrosion, or loose connections.
- Check the wiring harness leading to the MAP sensor for fraying, cuts, or pinched wires.
- If accessible, inspect the dual alternator system wiring and connections for any obvious faults.
- Use an OBD-II scanner to clear the code and test drive the vehicle to see if the code returns.
- If the code returns, consider replacing the MAP sensor as a common point of failure.
👨🔧 When to Call a Professional
If, after inspecting the MAP sensor and its wiring, the code persists, or if you suspect a fault with the dual alternator system, it is best to consult a professional mechanic. Diagnosing intermittent electrical faults and complex charging systems often requires specialized tools and expertise.
Commonly Asked Questions
Can I drive with a P1106 code?
It is generally not recommended to drive for extended periods with a P1106 code, as it can indicate issues affecting engine performance, fuel economy, or the charging system.
How do I know if it's the MAP sensor or the alternator?
Diagnosing requires checking live data from the MAP sensor with a scanner and inspecting the charging system, possibly with a multimeter, to isolate the fault.
Is P1106 related to boost pressure?
Yes, the MAP sensor measures manifold absolute pressure, which is crucial for determining engine load and for turbocharged or supercharged engines, boost pressure.
What does "intermittent high voltage" mean for the MAP sensor?
It means the MAP sensor circuit is sending a voltage signal that is occasionally higher than expected, suggesting a sensor fault, wiring short to voltage, or PCM issue.
Where is the MAP sensor located on a Ford?
The MAP sensor is typically located on the intake manifold or connected via a hose to the manifold. Its exact location can vary by model and engine type.