Diagnostic Aids

Check for any of the following conditions:

• Excessive deposits on throttle plate or throttle bore.
• A sticking or binding throttle plate.
• A misrouted wiring harness. Check MAF sensor harness to ensure harness is not routed too close to high voltage wires such as spark plug leads.
• A damaged wiring harness. Check wiring harness for damage. If harness appears to be okay, observe scan tool while moving connectors and wiring harnesses related to MAF sensor. A change in the display will indicate location of the fault.
• Observe Heated Oxygen (HO2S) voltage and fuel trim readings using a scan tool. If HO2S voltage is fixed low, while fuel trim is constantly high, check MAF sensor signal circuit for resistance. High circuit resistance can cause the sensor to read a lower volume of air than actual, resulting in a lean fueling condition.
• A plugged intake air duct or a dirty air filter element. A Wide Open Throttle (WOT) acceleration from a stop should cause MAF parameter displayed on a scan tool to increase from about 2-3.5 g/s at idle to about 90-100 g/s or more at the time of the 1-2 shift. If detected airflow is significantly smaller, check for a restriction or blockage in the intake air system.

An intermittent malfunction may be caused by a fault in MAF sensor circuit. Check wiring harness and components for an intermittent condition. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 1.8L VIBE article.

If DTC P0101 cannot be duplicated, information included in freeze frame data can be useful in determining vehicle operating conditions when the DTC was first set.