P1103

What it means

On Mazda, P1103 means the powertrain control module judged the mass air flow sensor signal to be inconsistent with engine speed. The module compares the airflow it measures with the airflow it expects for the current rpm and load, and it set the code when the two did not agree. The exact test conditions and the sensor design can vary by model and engine.

Symptoms

• Malfunction indicator lamp on
• Hesitation or poor throttle response
• Rough or unstable idle
• Hard starting or occasional stalling
• Poor fuel economy
• Reduced power or the engine running in a limited fallback mode

Possible causes

• Dirty or contaminated mass air flow sensor elementlikely
• Unmetered air leak after the sensor (split intake hose, loose clamp, leaking intake joint or vacuum hose)likely
• Restricted air filter or blocked intake tractpossible
• Wiring or connector fault on the sensor circuit (poor connection, corrosion, chafed wire, high resistance on supply or ground)possible
• Faulty mass air flow sensorpossible
• Exhaust restriction or an engine mechanical problem altering airflow (for example a blocked catalytic converter or valve timing fault)rare
• Fault in the powertrain control module or an outdated calibration, where the manufacturer has issued an updaterare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting engine speed, load, temperature and the airflow reading when the code set.
2. Inspect the air filter, intake hose and air box for damage, loose clamps, blockages or poor sealing.
3. Check the sensor connector and wiring for corrosion, bent pins, chafing and a secure fit, and look for any related wiring repairs.
4. Inspect the intake system and vacuum hoses for leaks after the sensor, and check for any oil or contamination on the sensor element.
5. With a scan tool, view live mass air flow at idle and at steady higher rpm and compare it with the specification for that engine, and check that the reading rises smoothly with revs.
6. Check fuel trims at idle and at around 2500 rpm; a large positive trim at idle that reduces with revs points to an air leak.
7. Test the sensor supply voltage, ground and signal against the manufacturer's data for that model.
8. Check for exhaust restriction and basic engine condition if the sensor and intake checks pass, and check for any applicable calibration update.

How to fix

• Clean the sensor element only using a method approved for that sensor type, or replace the sensor if it is damaged or out of specification.
• Repair or replace leaking, split or loose intake hoses, clamps and gaskets.
• Replace a blocked air filter and clear any intake restriction.
• Repair damaged wiring or connectors, or restore a poor ground or supply.
• Replace the mass air flow sensor if the live data and electrical tests show it is faulty.
• Apply a manufacturer calibration update if one is available for a known fault, then clear the code and road test.

Can I keep driving?

This code for other makes

• P1103MitsubishiTurbocharger Wastegate Actuator
• P1103OtherMAF Sensor In Range But Higher Than Expected
• P1103SubaruPressure Sources Switching Solenoid Valve Circuit
• P1103VolkswagenOxygen Sensor Heating Circuit Bank 1 Sensor 1 Short To B+

Nearby codes

• P1102MazdaMass Air Flow Sensor Signal Inconsistent With Throttle Position Sensor
• P1110MazdaIntake Air Temperature Sensor Signal Dynamic Chamber Circuit