Diagnostic Aids
Check for the following:
- Poor Connection at ECM pin YD10. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal to wire connection.
- Misrouted Harness. Inspect MAF sensor harness to ensure that it is not too close to high voltage wires, such as spark plug leads.
- Damaged Harness. Inspect harness for damage. If harness appears okay, observe ED21 display while moving related connectors and wiring harness. A change in display would indicate the intermittent fault location.
- Plugged Air Intake Filter. A WOT acceleration from a stop should cause MAF reading (ED21) to range from about 4.7 at idle, to 100 or greater at the time of 1-2 transmission shift. If not, check for air intake restriction.