Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2003 Mercury Sable, 2003 Mercury Mountaineer, 2003 Mercury Marauder, 2003 Mercury Grand Marquis, and 2003 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

Perform this test when directed by QUICK TEST. This test is intended to diagnose the following:

MAF Sensor
Wiring Harness Circuits (VPWR, PWR GND, MAF SIG & MAF RTN)
Powertrain Control Module (PCM)

To prevent replacement of good components, be aware the following non-EEC related areas may be cause of concern:

Air Cleaner Element
Inlet Air Duct
Throttle Body

For DTC P0102, a MAF V PID (MAF PID) reading less than 0.23 volt in Continuous Memory, or KOEO and KOER indicates a hard fault. For DTC P0103, a MAF V PID (MAF PID) reading less than 4.6 volts in Continuous Memory, or KOEO and KOER indicates a hard fault. Refer to illustration for specifications. See Figure.

NOTE: If the following test steps fail to diagnose MAF sensor concern, compare MAF sensor voltages with voltages in MASS AIRFLOW table in SENSOR OPERATING RANGE CHARTS article.