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Home >> Chrysler >> 2001 >> PT Cruiser Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0125: Closed Loop Temperature Not Reached >> Testing
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DTC P0125: Closed Loop Temperature Not Reached: Testing

NOTE: For best results, allow vehicle to cool overnight before performing test. Extremely cold ambient temperatures may have caused this DTC to set.
  1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP is displayed and equal to zero, go to next step. If GOOD TRIP is not displayed and equal to zero, go to step  5 .
    WARNING: DO NOT open cooling system when engine is hot.
  2. Check coolant level and condition. If coolant level and condition are okay, go to next step. If coolant level or condition is not okay, check for coolant leak and add necessary amount of coolant.
  3. Turn ignition on. Using scan tool, read engine coolant temperature. If vehicle was allowed to cool overnight, engine coolant temperature should be close to ambient temperature. If engine coolant temperature is more than 180°F (82°C), allow engine to cool until 150°F (66°C) is reached. Start engine. Monitor engine coolant temperature on scan tool while engine is warming up. Engine coolant temperature should increase smoothly to normal operating temperature. Thermostat should stay closed until engine coolant temperature reaches 192-199°F (89-93°C). If thermostat opens at specified temperature, go to next step. If thermostat does not open at specified temperature, replace thermostat.
  4. If engine coolant temperature increased smoothly and reached 180°F (82°C) or more, test is complete. If engine coolant temperature did not increase smoothly and reach 180°F (82°C) or more, check ECT sensor circuits for high resistance. Repair wiring as necessary. If wiring is okay, replace ECT sensor.
  5. Conditions that set DTC are not present at this time. Perform the following to help identify intermittent condition:
    • With engine running at normal operating temperature, wiggle related wiring harness while monitoring related parameters on scan tool. If voltage changes or DTC sets while wiggling wiring harness, repair connectors or wiring harness where wiggling caused voltage to change or DTC to set.
    • Review freeze frame information on scan tool. Duplicate conditions present when DTC was set.
    • Refer to any Technical Service Bulletins (TSBs) that may apply.
    • Visually inspect related wiring harness. Check for chafed, pierced, pinched or partially broken wires.
    • Visually inspect related wiring harness connectors. Check for broken, bent, pushed out or corroded terminals.

    If a problem is found, repair as necessary. If no problems are found, test is complete.

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