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P0102

Mass Air Flow Sensor Circuit Low Input

The engine computer is getting a weak signal from the mass air flow sensor. This usually happens when the sensor is unplugged, the wiring or connector is damaged, or the sensor has failed.

SEV
3/5
DRIVE
CAUTION
DIY
$0–$180
SHOP
$100–$350

Quick answer

AI-CITATION READY

What it means

P0102 means the powertrain control module has detected a mass air flow sensor signal voltage or frequency that is lower than the expected operating range. The MAF sensor measures incoming air so the PCM can calculate fuel delivery. When the signal is too low, the PCM may switch to backup values and turn on the check engine light.

Can you drive with it?

With caution. You can usually drive short distances, but the engine may run poorly, stall, or have reduced power. Fix it soon to avoid drivability problems and possible fuel economy issues.

Most common causes

  • MAF sensor unplugged
  • Damaged MAF wiring or loose, corroded connector terminals
  • Faulty mass air flow sensor

Typical repair cost

DIY usually runs $0–$180. Typical shop repair lands around $100–$350, depending on the root cause.

01 / Definition

P0102 means the powertrain control module has detected a mass air flow sensor signal voltage or frequency that is lower than the expected operating range. The MAF sensor measures incoming air so the PCM can calculate fuel delivery. When the signal is too low, the PCM may switch to backup values and turn on the check engine light.

02 / Drive status

With caution. You can usually drive short distances, but the engine may run poorly, stall, or have reduced power. Fix it soon to avoid drivability problems and possible fuel economy issues.

03 / Symptoms

  • Check engine light on
  • Rough idle
  • Hesitation during acceleration
  • Reduced engine power
  • Hard starting
  • Engine stalling
  • Poor fuel economy

04 / Causes

1MAF sensor unpluggedhigh
2Damaged MAF wiring or loose, corroded connector terminalshigh
3Faulty mass air flow sensorhigh
4Poor power or ground supply to the MAF sensormedium
5Air intake duct problem causing incorrect airflow measurementmedium
6PCM issuelow

05 / Diagnostic sequence

  1. 01Verify the code with a scan tool and check for related codes such as lean condition or other MAF circuit faults.
  2. 02Inspect the MAF sensor connector to make sure it is fully plugged in and locked.
  3. 03Check the connector terminals for corrosion, looseness, bent pins, or moisture.
  4. 04Inspect the wiring harness for damage, rubbing, broken wires, or previous repair issues.
  5. 05Inspect the air intake tube between the air filter box and throttle body for looseness or damage.
  6. 06Look at MAF data on a scan tool and compare readings to engine size and RPM for reasonableness.
  7. 07Test MAF power supply, ground, and signal circuit with a wiring diagram and multimeter.
  8. 08If wiring and power/ground are good, replace the MAF sensor and retest.

06 / Repairs

1Reconnect the MAF sensor if it is unplugged and clear the code.$0–$20
2Repair damaged wiring or clean and tighten loose or corroded MAF connector terminals.$10–$100
3Repair or replace the intake duct if it is damaged or not sealing properly.$20–$120
4Replace the faulty mass air flow sensor.$60–$180
5Perform circuit testing and advanced diagnosis if the problem remains.$100–$250

MFG / Manufacturer notes

These supplements add make-specific diagnostic framing. Pages without full matrix backing or lane approval stay guarded and canonicalize back here until they are explicitly approved for indexing.

  • Audi P0102

    Expansion-candidate noindex child page

    Open

07 / Related codes

  • P0100
  • P0101
  • P0103
  • P0104
  • P0171
  • P0174

08 / FAQ

Can a dirty or unplugged MAF sensor cause P0102?

Yes. An unplugged sensor is a very common cause, and a sensor with electrical problems can also trigger a low input code.

Will P0102 cause rough running?

Yes. The engine may idle roughly, hesitate, stall, or feel weak because fuel delivery is based on incorrect airflow information.

Should I replace the MAF sensor right away?

Not before checking the connector and wiring. A loose plug, damaged wires, or corroded terminals are common and can cause the same code.

09 / Source and method

DATA BASIS
OBD-II REFERENCE + OBD2.HELP
METHOD
STATIC VALIDATION
SAFETY
INFORMATIONAL

This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.

Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.

Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.