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?
![]() | ▶ Repair the trouble causing part and go to "Verification of Vehicle Repair". |
![]() | ▶ Go to "Power Circuit Inspection". |
Check power circuit voltage
IG KEY "OFF", ENGINE "OFF".
Disconnect Air-heater relay.
Measure the voltage between power terminal of Air-heater relay and chassis ground.
Specification : 11.5V~13.0V
Is the measured voltage within the specification?
![]() | ▶ Go to "2. Check IG KEY "ON" power circuit" . |
![]() | ▶ Repair problems of Air-heater FUSE in E/R JUNCTION BOX and related circuit and go to "Verification of Vehicle Repair". |
Check IG KEY "ON" power circuit
IG KEY "OFF", ENGINE "OFF".
Disconnect Air-heater relay
IG KEY "ON".
Measure the voltage between coil power terminal ofAir-heater relay and chassis ground.
Specification : 11.5V~13.0V
Is the measured voltage within the specification?
![]() | ▶ Go to "Control Circuit Inspection". |
![]() | ▶ Repair problems of INJ fuse in E/R JUNCTION BOX and related circuit and go to "Verification of Vehicle Repair". |
Check monitoring voltage in control circuit
IG KEY "OFF", ENGINE "OFF".
Disconnect Air-heater relay
IG KEY "ON".
Measure the voltage between coil control terminal of Air-heater relay and chassis ground.
Specification : 3.2V~3.7V
Is the measured voltage within the specification?
![]() | ▶ Go to "Component Inspection". |
![]() | ▶ When voltage is not detected : Go to "2. Check open in control circuit" as follows. ▶ When high voltage is detected : Repair short to battery and go to "Verification of Vehicle Repair". |
Check open in control circuit
IG KEY "OFF", ENGINE "OFF".
Disconnect Air-heater relay and ECM connector .
Check continuity between coil control terminal of Air-heater relay and ECM harness connector.
Specification : Continuity ( below 1.0Ω )
Is the measured resistance within the specification?
![]() | ▶ Repair short to ground and go to "Verification of Vehicle Repair". |
![]() | ▶ Repair open in control circuit and go to "Verification of Vehicle Repair". |