P1111 – OBD-II DTC

OBD-II DTC P1111 – Dual Alternator Lower Fault/ Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent High Voltage

DTC P1111 meaning

DTC P1111 refers to a diagnostic trouble code indicating a dual alternator lower fault or an intermittent high voltage condition in the Manifold Absolute Pressure (MAP) sensor circuit. This code is typically triggered when the Engine Control Module (ECM) detects a voltage reading from the MAP sensor that exceeds the expected range, suggesting a potential issue with the sensor or its wiring.

DTC P1111 symptoms

Common symptoms associated with DTC P1111 may include:

• Check Engine Light illuminated
• Engine performance issues, such as rough idling or stalling
• Decreased fuel efficiency
• Unusual engine noises
• Difficulty starting the engine

DTC P1111 causes

Several factors can lead to the triggering of DTC P1111, including:

• Faulty MAP sensor
• Wiring issues, such as frayed or shorted wires
• Corroded connectors in the MAP sensor circuit
• Faulty alternator or charging system problems
• Vacuum leaks affecting the MAP sensor readings

DTC P1111 seriousness

DTC P1111 can indicate a serious issue that may affect engine performance and efficiency. If left unaddressed, it can lead to further complications, such as engine damage or increased emissions. It is advisable to diagnose and resolve the issue promptly to maintain optimal vehicle operation.

How to diagnose DTC P1111

To diagnose DTC P1111, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P1111 code.
2. Inspect the MAP sensor and its wiring for any visible damage or corrosion.
3. Check the voltage and ground signals at the MAP sensor using a multimeter.
4. Test the MAP sensor by comparing its readings to manufacturer specifications.
5. Examine the alternator and charging system for any faults.
6. Look for vacuum leaks in the intake system that may affect MAP sensor readings.

How to fix DTC P1111 step-by-step instructions

To fix DTC P1111, follow these steps:

1. Repair or replace any damaged wiring or connectors in the MAP sensor circuit.
2. If the MAP sensor is faulty, replace it with a new one.
3. Address any issues found in the alternator or charging system.
4. Fix any vacuum leaks in the intake system.
5. Clear the DTC using an OBD-II scanner and test drive the vehicle to ensure the code does not return.

How to erase DTC P1111

To erase DTC P1111, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the engine to verify that the code does not reappear.

Recommended tools for OBD-II diagnostics

Explore our expert picks: The Best OBD2 Scanners for 2025

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.