Test 9 - Code 53/Low Temperature Switch
- Ensure that coolant temperature was above 128°F (53°C) during "Functional Test" when code was observed.
- Check contacts of mid temperature switch (should be closed above 128°F/53°C. If resistance measures less than 5 ohms, go to step 3). If above 5 ohms, replace mid temperature switch.
- Measure resistance in wiring between MCU (pin 5 & 14) and mid temperature switch. If resistance is less than 5 ohms, proceed with test. If greater than 5 ohms, repair wiring.
- Disconnect harness from mid temperature switch and measure resistance between wire leading to MCU pin 14 and ground. If resistance is less than 1000 ohms, repair wire leading to MCU pin 14. If resistance is greater than 1000 ohms, replace MCU.