P010A - Mass or Volume Air Flow Sensor 'B' Circuit
System
Powertrain (Engine & Gearbox)
Technical Description
The control module has detected a fault in the Mass or Volume Air Flow Sensor 'B' Circuit (P010A).
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Mass or Volume Air Flow Sensor 'B' Circuit – Airflow at Idle | Signal (g/s) | 2 - 6 g/s (warm idle) | Idling, all loads off |
| Mass or Volume Air Flow Sensor 'B' Circuit – Airflow at 3000 RPM | Signal (g/s) | 15 - 35 g/s (no load) | Stationary, raised RPM |
| Mass or Volume Air Flow Sensor 'B' Circuit – Signal (Voltage or Frequency) | Voltage (V) | 1.0 - 1.7 V idle / 2.0 - 4.5 V under load (frequency type: 2 - 10 kHz) | Ignition ON / engine running |
| MAF Supply Voltage | Voltage (V) | 11.8 - 14.4 V | Engine running at connector |
Idling, all loads off
Stationary, raised RPM
Ignition ON / engine running
Engine running at connector
Oscilloscope Waveform Analysis
200 ms/div, 1 V/divPossible Causes
Channel B:Verify dedicated wiring pins and signal pair for circuit B against the schematic.
Chafed or pinched wiring harness along the signal path to Mass or Volume Air Flow Sensor 'B' Circuit
Poor ground connection or excessive voltage drop (> 0.1 V) at the ground point for Mass or Volume Air Flow Sensor 'B' Circuit
Defective internal output driver or reference circuit in the control module for Mass or Volume Air Flow Sensor 'B' Circuit
Symptoms
4
Recommended Solution
Compare signal voltage and resistance between circuit B and companion circuit A at module connector.
Review freeze-frame environmental data and perform fundamental voltage-drop and resistance checks on the circuit.
Verify loaded supply voltage and harness terminal pins at Mass or Volume Air Flow Sensor 'B' Circuit.
Check circuit continuity and ground-side voltage drop (< 0.05 V) for Mass or Volume Air Flow Sensor 'B' Circuit.
Log MAF airflow (g/s) during a wide-open-throttle (WOT) pull against target displacement specs.
Mechanic's Tip
A failing MAF often drives extreme long-term fuel trims (LTFT) without setting a direct MAF code. Always verify if trim deviation tracks airflow changes before blaming the O2 sensor.