Codes 53/54 - Temperature Switch Open
Code 53 is for Dual Temperature Switch, code 54 is for Mid Temperature Switch. Before testing, ensure temperature of coolant is between 140-200°F (60-93°C).
- Disconnect vehicle harness from switch. Connect ohmmeter across switch terminals and measure resistance. If resistance is greater than 5 ohms, replace switch. If less than 5 ohms, go to next step.
- Connect one lead of ohmmeter to MCU pin 7, then 17, and the other lead to ground. If resistance is 1000 ohms or less in either location, repair circuit. If resistance is 1000 ohms or more, proceed with test.
- Disconnect MCU harness connector. Check continuity of circuits from MCU connector to switch connector. (Pins 7 & 14 for Dual-Temp. Switch; pins 14 & 17 for Mid-Temp Switch). If resistance is greater than 5 ohms, repair circuit. If less than 5 ohms, replace MCU module.