P0106

What it means

P0106 means the engine control unit has found that the signal from the manifold absolute pressure (MAP) sensor, or the barometric pressure reading, is plausible electrically but does not match what it expects. It usually compares the MAP reading with throttle position, engine speed, load and barometric pressure, and sets the code when they disagree for too long. The fault is a range or performance problem rather than a plain open or short circuit.

Symptoms

• Engine management light on
• Rough or unstable idle
• Hesitation or poor acceleration
• Hard starting or occasional stalling
• Poor fuel economy
• Black smoke or a rich or lean running condition

Possible causes

• Vacuum leak or split, loose or blocked vacuum hose to the MAP sensorlikely
• Faulty or contaminated MAP sensor reading out of rangelikely
• Intake leak after the throttle body, such as a manifold gasket, intake hose or boost pipe leaklikely
• Wiring or connector fault causing high resistance, poor reference voltage or poor earth on the sensor circuitpossible
• Restricted exhaust or blocked air intake changing manifold pressurepossible
• Mechanical engine problem such as incorrect valve or cam timing affecting manifold vacuumrare
• Fault in the engine control unitrare

How to diagnose

1. Read the stored codes and freeze frame data, noting engine speed, load, throttle position and coolant temperature when the fault set, and check for other related codes.
2. Inspect the MAP sensor, its connector and wiring for damage, corrosion, oil contamination, chafing or poor pin tension.
3. Check the vacuum hose to the sensor (if fitted) and the intake system for splits, loose clips, blocked pipes and leaks, including boost pipes on turbo engines.
4. With the ignition on and engine off, compare the live MAP reading with barometric pressure. It should be close to the local ambient value, and the exact expected figure depends on the model.
5. Start the engine and watch the live MAP value at idle and when snapping the throttle. Look for a steady, responsive change in line with throttle position, and compare it with a known good vacuum or pressure gauge reading.
6. Check the sensor supply voltage, signal and earth with a multimeter against the manufacturer's specification for the engine.
7. Carry out a smoke test on the intake system to find small leaks that are not obvious by eye.
8. Check for exhaust restriction and air filter or intake blockage, and check engine mechanical condition if the sensor and wiring prove good.

How to fix

• Repair or replace split, loose or blocked vacuum hoses and fix any intake or boost leaks.
• Replace the MAP sensor if its readings are out of range or it is contaminated and cannot be cleaned according to the manufacturer's guidance.
• Repair damaged wiring, terminals or connectors, and restore correct supply and earth to the sensor.
• Replace a blocked air filter, or clear any exhaust or intake restriction found.
• Correct any mechanical fault found, such as valve timing, following the manufacturer's procedure.
• Clear the code after the repair and road test to confirm it does not return.

Can I keep driving?

Nearby codes

• P0105GenericManifold Absolute Pressure/Barometric Pressure Sensor Circuit
• P0107GenericManifold Absolute Pressure/Barometric Pressure Sensor Circuit Low