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Part 4 - Diagnosis and T
roubleshooting
4.5.4 Procedure
E3 / E4 / E5 / E7 / Eb / Ed /EE/ EF / EP
/ EU / Fb / F9 / Fd
Temperature sensor or pressure sensor
connection on main PCB is loose
1
No
No
Yes
Yes
Temperature or pressure sensor has
short-circuited or failed
2
Replace main PCB
Ensure the sensor is connected properly
Replace the sensor
Notes:
1. For 30kW and 60kW units, all the sensors are connected to port CN1, CN16, CN31, CN3,CN10 and CN69 on the main PCB (labeled 10, 9, 8, 7, 6, 4 in Figure 4-2.1
in Part 4, 2.2 “Main PCB”).
2. Measure sensor resistance. If the resistance is too low, the sensor has short-circuited. If the resistance is not consistent with the sensor’s resistance
characteristics table, the sensor has failed. Refer to Table 5-5.1 or 5-5.2 or 5-5.3 in Part 5, 5.1 “Temperature Sensor Resistance Characteristics”.
