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DTC B1115 Electric water pump malfunction
 
 
 
 
DTC SET CONDITION
This code will be set when the heater water pump assembly does not operate for 30 seconds.
noteIf the ambient temperature is 0°C (32°F) or less, this code will be set when the pump assembly does not operate for 10 minutes or more.
 
 
Past trouble
Probably a foreign material was trapped in the heater water pump for some time, which caused the pump speed to decrease. Then the foreign material was eliminated.
Now the foreign material has been eliminated. Execute No.23 Electric water pump on the actuator test. If the pump operates normally, the malfunction can be determined as an intermittent malfunction.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the heater water pump assembly
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
  • Malfunction of the heater controller assembly (A/C-ECU)
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the engine coolant level.
Check that the coolant level in the condenser tank is between "F" and "L".
Is the engine coolant level correct?
Go to Step 2.
Adjust the engine coolant level (Refer to GROUP 14A - On-vehicle Service, Engine coolant change ).
 
STEP 2. Check the heater water pump relay.
Refer to .
Is the check result normal?
Go to Step 3.
Replace 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.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.
 
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.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.
 
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.
Is the check result normal?
Go to Step 8.
Repair the connector(s) or wiring harness.
 
STEP 8. Check of open circuit in EWPB line between heater water pump relay connector and heater controller assembly (A/C-ECU) connector.
Is the check result normal?
Go to Step 9.
Repair the connector(s) or wiring harness.
 
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.
Is the check result normal?
Go to Step 10.
Repair the connector(s) or wiring harness.
 
STEP 10. Using scan tool (M.U.T.-IIISE), check the actuator test.
(1)
cautionTo 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.