P010B

What it means

P010B is the generic code for a Mass or Volume Air Flow Sensor 'B' circuit range/performance fault. The engine control unit has compared the signal from the second air flow sensor with the readings it expects from other inputs, such as throttle position, engine speed, load and the other air flow sensor. It found the signal to be implausible, even though the circuit is not necessarily open or shorted. Sensor 'B' is normally found on engines with two intake paths or two air flow sensors, and its location depends on the model and engine.

Symptoms

• Engine warning light on
• Poor or hesitant acceleration
• Rough or unstable idle
• Hesitation, surging or stalling
• Poor fuel economy
• Engine running rich or lean, possibly with black smoke or hard starting

Possible causes

• Contaminated or faulty air flow sensor B element giving an inaccurate readinglikely
• Unmetered air leak after the sensor, such as a split intake hose, loose clamp or leaking intake jointlikely
• Restricted or poorly fitted air filter or intake ducting affecting the airflow readingpossible
• Wiring or connector problems such as corrosion, high resistance, a poor earth or a poor supply to the sensorpossible
• Crankcase breather or vacuum leak upsetting the air measurement on that intake bankpossible
• Exhaust leak or other fault upstream of the oxygen sensors that distorts fuelling and the plausibility checksrare
• Faulty engine control unit or an outdated calibration, only where the manufacturer has documented it as a known causerare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data (load, engine speed, temperature) from when the fault set.
2. Identify which sensor is 'B' on this model and engine, using the manufacturer's information, as the layout varies.
3. Visually inspect the air filter, intake ducting, clamps and the sensor housing for damage, dirt, oil contamination or loose fittings.
4. Check the sensor connector and wiring for corrosion, bent pins, chafing and a secure fit, and test the supply, earth and signal circuits against the specification.
5. Compare live air flow readings from sensor B with sensor A (if fitted), at idle and at steady higher revs, and check they are plausible for the engine size.
6. Check short and long term fuel trims; a large positive trim suggests unmetered air, a large negative trim suggests over-reading.
7. Smoke test the intake and breather system to find air leaks and check for vacuum leaks.
8. Check for related codes such as fuel trim, misfire or oxygen sensor faults that point to a wider cause.

How to fix

• Clean the sensor only if the manufacturer permits it, using the approved method; otherwise replace a faulty air flow sensor.
• Repair or replace leaking, split or loose intake hoses, clamps and breather pipes.
• Replace a blocked air filter and refit the intake ducting correctly.
• Repair damaged wiring, terminals or earth connections, and refit the connector securely.
• Fix any exhaust leak or related fault found during testing.
• Where a documented fault exists, update the control unit software to the latest manufacturer calibration.

Can I keep driving?

Nearby codes

• P010AGenericMass or Volume Air Flow Sensor B Circuit
• P010CGenericMass or Volume Air Flow Sensor B Circuit Low