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HOMESERVICE MANUALSTOYOTA2004MATRIX XR, FWD, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 508 (ENGINE CONTROL SYSTEM (SFI) - DIAGNOSIS)DTC P1121: COOLANT FLOW CONTROL VALVE POSITION SENSOR CIRCUIT STUCKINSPECTION PROCEDURENOTES
2004 Toyota Matrix XR, FWD, Standard

Inspection Procedure: Notes

2004 Toyota Matrix XR, FWD, StandardSECTION Notes
WARNING: This page is about a different car, the 2004 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: Be careful when replacing any part in the system or changing the coolant because the coolant in the heat storage tank is hot even if the engine is cold.

HINT:

  • If DTCs P1121 and P1150 are detected simultaneously, there may be malfunction in the water valve system.
  • If DTC P1121 is detected, coolant passages may be clogged.
  • To check the coolant heat storage (CHS) system, the ECM may cause the water pump of the CHS system to operate 5 hours after the power switch has been turned OFF.
  • Read freeze frame data using the intelligent tester II. Freeze frame data records the engine condition when malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

Hand-held tester: 

  1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P1121) 
    1. Connect the hand-held tester to the DLC3.
    2. Turn the power switch ON (IG).
    3. Turn the hand-held tester ON.
    4. On the hand-held tester, select the item: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
    5. Read DTCs.
    DTC OUTPUT (IN ADDITION TO DTC P1121)

    Display (DTC Output) Proceed to
    P1121 A
    P1121 and other DTCs B

    HINT:

    If any other codes besides P1121 are output, perform troubleshooting for those DTCs first.

    B: GO TO RELEVANT DTC CHART (See  DIAGNOSTIC TROUBLE CODE CHART   ) 

    A: Go To Next Step 

  2. PERFORM ACTIVE TEST BY HAND-HELD TESTER 
    1. Connect the hand-held tester to the DLC3.
    2. Turn the power switch ON (IG).
    3. Turn the hand-held tester ON.
    4. Put the engine in inspection mode (see INFORMATION ).
    5. Start the engine and warm it up.
    6. Select the items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / WATER FLW VLV3, WATER FLW VLV4 or WATER FLW VLV5.
    7. Measure the voltage between terminals WBAD and E2 of the ECM connector.
    ACTIVE TEST BY HAND-HELD TESTER (DTC P1121)

    Tester Operation Specified Condition
    "WATER FLW VLV 3" ON Approximately 2.5 V
    "WATER FLW VLV 4" ON Approximately 3.5 V
    "WATER FLW VLV 5" ON Approximately 4.5 V

    NG: REPLACE WATER W/BRACKET VALVE ASSY 

    OK: Go To Next Step 

  3. CHECK COOLING SYSTEM (CHECK FOR CLOGGING IN THE COOLANT SYSTEM) 

    OK: Coolant passages are not clogged. 

    NG: REPAIR OR REPLACE COOLING SYSTEM 

    OK: REPLACE ECM (See  ENGINE CONTROL SYSTEM  ) 

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.