STEP 1. Check the engine coolant level.
STEP 2. Check the heater water pump relay.
STEP 3. Voltage measurement at heater water pump relay connector.
(1) Remove the relay, and measure at the relay block side.
(2) Voltage between heater water pump relay terminal 4 and body ground.OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 5. Go to Step 4.
STEP 4. Check of open or short circuit in power supply or ground line between fusible link and heater water pump relay connector terminal 4.
STEP 5. Voltage measurement at heater water pump relay connector.
(1) Remove the relay, and measure at the relay block side.
(2) Voltage between heater water pump relay terminal 2 and body ground.OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 7. Go to Step 6.
STEP 6. Check of open or short circuit in power supply or ground line between fusible link and heater water pump relay connector terminal 2.
STEP 7. Check of open or short circuit in power supply or ground line between heater water pump assembly and heater water pump relay connector terminal 3.
STEP 8. Check of open circuit in EWPB line between heater water pump relay connector and heater controller assembly (A/C-ECU) connector.
STEP 9. Check of open or short circuit of ground in EWPS line between heater water pump assembly connector and heater controller assembly (A/C-ECU) connector.
STEP 10. Using scan tool (M.U.T.-IIISE), check the actuator test.
(1) caution | To prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF position before connecting or disconnecting scan tool (M.U.T.-IIISE). |
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect Scan Tool (M.U.T.-IIISE)
".
(2) Carry out the actuator test (Refer to ).Item No.23: Electric water pump
Does the water heater fluid can be confirmed?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ). Go to Step 11.
STEP 11. After replacing the heater water pump assembly (Refer to
), using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Recheck the DTC.(1) Erase the DTC.
(2) Electric motor switch: OFF to ON
(3) Check the DTC.
Is the DTC set?
Replace the heater controller assembly (A/C-ECU) (Refer to ). This diagnosis is complete.