Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found ?

	▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
	▶ Go to "Power Circuit Inspection" procedure.

IG "OFF" and Disconnect MAFS connector.

IG "ON".

Measure voltage between power terminal of MAFS harness connector and chassis ground.

Is the measured voltage within specification ?

	▶ Go to "Signal Circuit Inspection" Procedure.
	▶ Check fuse between MAFS and main relay is open or not installed.

IG "OFF" and Disconnect MAFS connector.

IG "ON".

Measure voltage between signal terminal of MAFS harness connector and chassis ground.

Is the measured voltage within specification ?

	▶ Go to " Ground circuit inspection" procedure.
	▶ If the measured voltage is "0", go to "Check open in harness" as follows. If the measured voltage is over "5V", go to "Check short to battery in harness" as follows.

IG "OFF" and disconnect MAFS and ECM connector.

Measure resistance between signal and power terminals of MAFS harness connector.

Measure resistance between signal terminal of MAFS harness connector and signal terminal of IATS harness connector.

Is the measured resistance within specification ?

	▶ Go to "Check short to ground in harness" as follows.
	▶ Repair short to battery in harness and go to "Verification of Vehicle Repair" procedure.

IG "OFF" and disconnect MAFS and ECM connector.

Measure resistance between signal terminal of MAFS harness connector and chassis ground.

Is the measured resistance within specification ?

	▶ Go to "Check open in harness" as follows.
	▶ Repair short to ground in harness and go to "Verification of Vehicle Repair" procedure.

IG "OFF" and disconnect MAFS and ECM connector.

Measure resistance between signal terminal of MAFS harness connector and MAFS signal terminal of ECM harness connector.

Is the measured resistance within specification ?

	▶ Go to "Ground circuit Inspection" procedure.
	▶ Repair open in harness and go to "Verification of Vehicle Repair" procedure.

IG "OFF" and disconnect MAFS connector and then IG "ON".

Measure voltage between signal terminal of MAFS harness connector and chassis ground.(Measurement "A")

Measure voltage between signal and ground terminals of MAFS harness connector.(Measurement "B")

Is the measured voltage within specification ?

	▶ Go to "Component Inspection" procedure.
	▶ Repair contact resistance or open in harnesss and then go to "Verification of Vehicle Repair" procedure.