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Low Temperature Switch

  1. Ensure that coolant temperature was above 95°F (35°C) during "Functional Test" when code was observed.
  2. Disconnect harness connector from switch. Check contacts of low temperature switch (should be closed above 95°F/35°C). If resistance measures 5 ohms or less, go to next step. If above 5 ohms, replace low temperature switch and retest.
  3. Disconnect harness connectors at MCU and switch. Measure resistance in wiring between MCU (pins 5 & 14) and low temperature switch. If resistance is 5 ohms or less, go to next step. If greater than 5 ohms, repair wiring and retest.
  4. Disconnect harness from low temperature switch and measure resistance between wire leading to MCU pin 5 and ground. If resistance is 1000 ohms or less, repair wire leading to MCU pin 5 and retest. If resistance is greater than 1000 ohms, replace MCU and retest.
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