Electrical systems consist of a lot of harness and connectors, poor connection of terminals can cause various problems and damge of component.
Perform checking procedure as follows.
Check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.
Check connecting condition of ECM and component connector : Check terminal seperation, damage of locking device and connecting condition between terminal and wiring.
Disconnect the pin which requires checking at male connector and insert it to the terminal at female connector for checking connecting condition. ( after checking, reconnect the pin at correct position. )
Is the problem found?
YES
Repair the trouble causing part and go to "Verification of Vehicle Repair".
NO
Go to "Power Circuit Inspection".
Check power circuit voltage
IG KEY "OFF", ENGINE "OFF".
Disconnect MAFS connector.
IG KEY "ON".
Measure the voltage of MAFS connector terminal 1 and terminal 4.
Specification :
Terminal 1 : 11.5V~13.0V ( IG Power )
Terminal 4 : 4.8V~5.1V ( Sensor power )
Is the measured voltage within the specification?
YES
Go to "Signal Circuit Inspection".
NO
When output voltage is not detected at terminal 1 :
☞ Repair open in E/R junction box 10A SNSR. 2 FUSE and related circuit and go to "Verification of Vehicle Repair".
When output voltage is not detected at terminal 4 :
☞ Repair open between MAFS connector terminal 4 and ECM connector (CDD-A) terminal 37, and go to "Verification of Vehicle Repair".
Check signal circuit voltage
IG KEY "OFF", ENGINE "OFF".
Disconnect MAFS connector.
IG KEY "ON".
Measure the voltage of MAFS connector terminal 5.
Specification : 4.8V~5.1V
Is the measured voltage within the specification?
YES
Go to "Ground Circuit Inspection".
NO
Go to "2. Check open in signal circuit" as follows.
Check open in signal circuit
IG KEY "OFF", ENGINE "OFF".
Disconnect MAFS sensor connector and ECM connector.
Check continuity between MAFS connector terminal 5 and ECM connector (CDD-A) terminal 42.
Specification : Continuity ( below 1.0Ω )
Is the measured resistance within the specification?
YES
Go to "3. Check short to ground in signal circuit" as follows.
NO
Repair open in signal circuit and go to "Verification of Vehicle Repair".
Check short to ground in signal circuit
IG KEY "OFF", ENGINE "OFF"
Disconnect MAFS sensor connector and ECM connector.
Check continuity between MAFS connector terminal 5 and chassis ground.
Specification : Discontinuity(Infinite Ω )
Is the measured voltage within the specification?
YES
Go to "Ground Circuit Inspection".
NO
Repair short to ground in signal circuit and go to "Verification of Vehicle Repair".
IG KEY "OFF", ENGINE "OFF".
Disconnect MAFS connector.
IG KEY "ON".
Measure the voltage of MAFS connector terminal 4. [ TEST "A" ]
Measure the voltage between MAFS connector terminal 4 and terminal2. [ TEST "B" ]
( terminal 4 : Check + prove , terminal 2 : Check - prove )
Specification : [TEST "A"] Voltage - [TEST "B"] Voltage = below 200mV
Is the measured voltage within the specification?
YES
Go to "Component Inspection".
NO
When "B" voltage is not detected : Repair open in ground circuit and go to "Verification of Vehicle Repair".
When the voltage difference between "A" and "B" is above 200mV : Eliminate the causes of excessive resistance and go to "Verification of Vehicle Repair".