W/Harness Inspection

Terminal and Connector Inspection

1. 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.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found ?
YES
> Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
> Go to "Power Circuit Inspection" procedure.

Power Supply Circuit Inspection

Check voltage
1. IG "OFF" and Disconnect MAFS connector.
2. IG "ON" & ENG "OFF"
3. measure voltage between power terminal of MAFS harness connector and chassis ground
A. Specification : B+




4. Is the measured voltage within specification ?
YES
> Go to "Signal Circuit Inspection" Procedure.
NO
> Check fuse between MAFS and main relay is open or not installed.
> Repair open in power harness between MAFS and main relay and go to "Verification of Vehicle Repair" procedure.

Signal Circuit Inspection

Check voltage
1. IG "OFF" and disconnect MAFS connector.
2. IG "ON" & ENG "OFF".
3. Measure voltage between signal terminal of MAFS harness connector and chassis ground.
A. Specification : Approx. 5V




4. Is the measured voltage within specification ?
YES
1) Go to "Ground circuit inspection" procedure.
NO
1) 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.
Check short to battery in harness
1. IG "OFF" and disconnect MAFS and PCM connector.
2. Measure resistance between signal and power terminals of MAFS harness connector.
3. Measure resistance between signal terminal of MAFS harness connector and signal terminal of IATS harness connector.
A. Specification : Infinite




4. Is the measured resistance within specification ?
YES
1) Go to "Check short to ground in harness" as follows.
NO
1) Repair short to battery in harness and go to "Verification of Vehicle Repair" procedure.
Check short to ground in harness
1. IG "OFF" and disconnect MAFS and PCM connector.
2. Measure resistance between signal terminal of MAFS harness connector and chassis ground.
A. Specification : Infinite




3. Is the measured resistance within specification ?
YES
1) Go to "Check open in harness" as follows.
NO
1) Repair short to ground in harness and go to "Verification of Vehicle Repair" procedure.
Check open in harness
1. IG "OFF" and disconnect MAFS and PCM connector.
2. Measure resistance between signal terminal of MAFS harness connector and MAFS signal terminal of PCM harness connector.
A. Specification : Approx. below 1 Ohm.




3. Is the measured resistance within specification ?
YES
1) Go to "Ground circuit Inspection" procedure.
NO
1) Repair open in harness and go to "Verification of Vehicle Repair" procedure.

Ground Circuit inspection

Check open in harness
1. IG "OFF" and disconnect MAFS connector and then IG "ON".
2. Measure voltage between signal terminal of MAFS harness connector and chassis ground (Measurement "A")
3. Measure voltage between signal and ground terminals of MAFS harness connector (Measurement "B")
A. Specification : Voltage difference between Measurement "A" and "B" is below 200 mV.








4. Is the measured voltage within specification ?
YES
> Go to "Component Inspection" procedure.
NO
> Repair contact resistance or open in harness and then go to "Verification of Vehicle Repair" procedure.