Code 33 - Mass Air Flow (MAF) Sensor

The MAF sensor measures the flow of air entering the engine. This information is used by the ECM for fuel control. To set Code 33 the following conditions must be met for 5 seconds or more:

Engine idling.
TPS is 10% or less.
Air flow is more than 150 grams per second (high frequency).

NOTE: The following step numbers refer to the numbers in the accompanying flow chart(s).

This test checks if ECM recognizes a problem.
Inspect wire routing of high voltage wires such as spark plug wires. Such wires routed too closely to MAF wiring harness could possibly cause an intermittent Code 33.

Fig 1: Flow Chart, Code 33: Mass Air Flow (MAF) Sensor (All Engines)

Fig 2: Flow Chart, Code 33: Mass Air Flow (MAF) Sensor (All Engines)

Fig 3: Schematic, Code 33: Mass Air Flow (MAF) Sensor (All Engines)