LEMON Manuals: Even more car manuals for everyone
Home >> Mazda >> 2022 >> CX-5 Turbo Signature >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 14 (On-Board Diagnostic - Engine Control System (VIN M) (2 Of 7)) >> DTC P0126-00: Thermostat Stuck Open >> Details On DTCs

Details On DTCs

WARNING: This page is about a different variant/trim than selected.
DTC P0126-00: (PCM, VIN M) DETECTION CONDITION AND POSSIBLE CAUSE

DESCRIPTION Thermostat stuck open
DETECTION CONDITION Determination conditions
  • If any of the following conditions is met under condition A or condition B:

    Condition A:

    • ECT sensor No. 2 value is less than 73.9 °C {165 °F}

    Condition B:

    • ECT sensor No. 1 value is less than 60.1 °C {140 °F}
Preconditions Condition A:
  • If the following condition is implemented 3 times or more.
    • Vehicle is driven for approx. 35.9 s at a speed of 40 km/h {25 mph}, and the frequency of engine coolant heat radiation amount *1 of 240.4 W/K is higher compared to 240.4 W/K or less
  • The actual engine coolant temperature is 18.9 °C {34 °F} higher than the estimated ambient temperature calculated by the PCM based on the values input.
  • ECT sensor No. 1 value at engine start: -10-57.5 °C {14-136 °F}*2
  • Estimated ambient air temperature: -10-45 °C {14-113 °F}*2
  • Target coolant control valve position: more than 59 °
  • Within 25 min after engine start
  • A certain period of time has elapsed (fluctuates depending on engine coolant temperature and engine coolant flow amount) since ECT sensor No. 1 is 50 °C {122 °F} or more
  • The following DTCs are not detected:
    • Fuel system malfunction: P0171-00:, P0172-00:, P2096-00:, P2097-00:
   
  • ECT sensor No. 1 malfunction: P0117-00:, P0118-00:
  • ECT sensor No. 2 malfunction: P2184-00:, P2185-00:
    • MAF sensor malfunction: P0100-00:, U060F-00:
Condition B:
  • If the following condition is implemented 3 times or more.
    • Vehicle is driven for approx. 35.9 s at a speed of 40 km/h {25 mph}, and the frequency of engine coolant heat radiation amount *1 of 240.4 W/K is higher compared to 240.4 W/K or less
  • The actual engine coolant temperature is 18.9 °C {34 °F} higher than the estimated ambient temperature calculated by the PCM based on the values input.
  • ECT sensor No. 1 value at engine start: -10-57.5 °C {14-136 °F}*2
  • Estimated ambient air temperature: more than -10 °C {14 °F}
  • Target coolant control valve position: more than 59 °
  • The following conditions continue for 2 s or more.
    • ECT sensor No. 1 value: more than 73.9 °C {165 °F}
      • ECT sensor No. 1 value: 70.9 °C {160 °F} or less
  • A certain period of time has elapsed (fluctuates depending on engine coolant temperature and engine coolant flow amount) since ECT sensor No. 1 is 50 °C {122 °F} or more
  • The following DTCs are not detected:
    • Fuel system malfunction: P0171-00:, P0172-00:, P2096-00:, P2097-00:
    • ECT sensor No. 1 malfunction: P0117-00:, P0118-00:
    • ECT sensor No. 2 malfunction: P2184-00:, P2185-00:
      • MAF sensor malfunction: P0100-00:, U060F-00:
*1 : The engine coolant heat radiation amount is the value calculated by the PCM.*2 : Standard can be verified by displaying PIDs using M-MDS
  Drive cycle
Self test type
  • CMDTC self test
Sensor used
  • Desired engine coolant temperature: intake air temperature (IAT sensor), engine speed (CKP sensor), charging efficiency
  • Actual engine coolant temperature: ECT sensor No. 1/No. 2
FAIL-SAFE FUNCTION
  • Not applicable
VEHICLE STATUS WHEN DTCs ARE OUTPUT
  • Illuminates check engine light.
  • Heating is ineffective after engine is started
POSSIBLE CAUSE
  • ECT sensor No. 1 malfunction
  • ECT sensor No. 2 malfunction
  • Poor assembly of ECT sensor
  • Poor assembly of engine coolant hose (engine coolant passage malfunction)
  • Poor engine coolant, leakage, or freezing
  • Use of unspecified engine coolant
  • Foreign matter caught in thermostat (foreign matter penetration in engine coolant)
  • Thermostat (built-into coolant control valve) malfunction
  • PCM malfunction