P0102

Read the instructions below then start the fault diagnostic procedure.

Symptom: CHECK ENGINE goes on after two driving cycles. Engine speed drops slower than normal when accelerator pedal is released. Misfiring can occur before trouble code is generated.

P0102

Fault symptoms

•	CHECK ENGINE goes on after two driving cycles.

•	Engine speed drops slower than normal when accelerator pedal is released.

•	Misfiring can occur before trouble code is generated.

Conditions

The following conditions apply for this DTC.

•	Crankshaft rotating and main relay voltage exceeding 10V.

•	Frequency lower than 500 Hz for more than 0.5 s.

Diagnostic help

The mass air flow sensor is sending pulses to the control module but the frequency is too low. Consequently, the sensor is powered and is in contact with the control module input.

In most cases, this diagnostic trouble code indicates an internal fault in the sensor but also a very large leak between the sensor and the throttle. This diagnostic trouble code will be generated if the sensor is removed, for example.

Functions in the diagnostic tool related to the fault are:

•	Mass air flow sensor value, unit g/s.

•	Air mass deviation from calculated, unit %.

See also description of test readings, , for more information.

Checking the wiring

Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.