SFI SYSTEM(w/ Canister Pump Module), Diagnostic DTC:P012800

DTC Code DTC Name
P012800 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

DESCRIPTION

This DTC is stored when the engine coolant temperature does not reach 75°C (167°F) despite sufficient engine warm-up time having elapsed.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory Note
P012800 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

All of the following conditions are met for 5 seconds or more (2 trip detection logic):


  1. Cold start.

  2. The engine is warmed up.

  3. The engine coolant temperature is less than 75°C (167°F).

  • Water inlet with thermostat sub-assembly

  • Engine cooling system

  • Engine coolant temperature sensor

  • ECM

 Comes on DTC stored SAE Code: P0128

MONITOR DESCRIPTION

B005M5UE49

The ECM estimates the engine coolant temperature based on the starting temperature, engine loads, and engine speeds. The ECM then compares the estimated temperature with the actual engine coolant temperature. When the estimated engine coolant temperature reaches 75°C (167°F), the ECM checks the actual engine coolant temperature. If the actual engine coolant temperature is less than 75°C (167°F), the ECM interprets this as a malfunction in the thermostat or the engine cooling system and stores the DTC.

MONITOR STRATEGY

Frequency of Operation Once per driving cycle

CONFIRMATION DRIVING PATTERN

B005LQ9E23

  1. Stop the engine and allow it to soak.

  2. Connect the GTS to the DLC3.

  3. Turn the engine switch on (IG) and turn the GTS on [A].

  4. Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature and Intake Air Temperature.

  5. Check that "Coolant Temperature" is 56°C (133°F) or less and "Intake Air Temperature" is between 0 and 35°C (32 and 95°F).

  6. Set the heater to MAX HOT with fresh air mode selected and turn the A/C off.

  7. Start the engine and drive the vehicle at 80 km/h (50 mph) or more for 20 minutes [B].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    Tech Tips


    • Data can be captured relatively easily by using the snapshot function in the Data List.

    • Enter the following menus: Data List / Function / Snapshot Configure / Duration / Maximum.

    • Data capture can be started by using the target point function. For example, setting the target point to an engine speed of 4000 rpm and then racing the engine, etc. to raise the engine speed to a speed of 4000 rpm or higher will cause data capture to start.

  8. After "Coolant Temperature" stabilizes, check that "Coolant Temperature" is 75°C (167°F) or higher [C].

    Tech Tips

    If "Coolant Temperature" is less than 75°C (167°F) while driving the vehicle at 80 km/h (50 mph), inspect the engine cooling system and thermostat.

CAUTION / NOTICE / HINT

Tech Tips


  • When the DTC is output, check the engine coolant temperature using the GTS. Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature. If the Coolant Temperature value is lower than the actual engine coolant temperature, the engine coolant temperature sensor circuit may be malfunctioning. In this case, check the wire harnesses and connectors (and those connections) between the ECM and the engine coolant temperature sensor first.

  • Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P012800)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Trouble Codes.

    5. Read the DTCs.


      Powertrain > Engine > Trouble Codes
      Result
      Result Proceed to
      DTC P012800 is output A
      DTC P012800 and other DTCs are output B

      Tech Tips

      If any DTCs other than P012800 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. CHECK ENGINE COOLING SYSTEM


    1. Check for defects in the engine cooling system that might cause the system to be too cold, such as abnormal cooling fan operation or any modifications.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE ENGINE COOLING SYSTEM

    OK

  3. INSPECT WATER INLET WITH THERMOSTAT SUB-ASSEMBLY


    1. Inspect the water inlet with thermostat sub-assembly (thermostat opening temperature).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE WATER INLET WITH THERMOSTAT SUB-ASSEMBLY Click here

    OK

  4. INSPECT ENGINE COOLANT TEMPERATURE SENSOR


    1. Inspect the engine coolant temperature sensor.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the engine coolant temperature sensor.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here