Proheat M125 - Manual (Page 65)

3. Analog temperature sensor open.
4. Digital temperature sensor not communicating with the G-II PCM.
Troubleshoot the Dual Mode Temperature Sensor Diagnostic Code based on
coolant flow first:
Coolant Flow Go to page 4-24, Steps 1 & 2.
If the Coolant flow is correct and the Temp Sensor/Coolant Flow code is still
indicated the Dual Mode Temperature Sensor, the wiring or the G-II PCM is
faulty. Inspect the G-II PCM connector for damage and corrosion. Inspect the
Dual Mode Temperature sensor harness and connector for damage and
corrosion. If no damage or corrosion is found.
Go to Dual Mode Temperature Sensor
replacement, on this page.
Figure 4-29: Temperature Sensor.
DUAL MODE TEMP
SENSOR
Temperature Sensor replacement:
a) Isolate the coolant system at the PROHEAT inlet and outlet ports for
minimal coolant loss using valves in the system or hose clamps.
b) Remove main sensor mount using a 1" wrench.
c) Reinstall the new sensor. Ensure that the O-ring and
O-ring seat are clean. Install the sensor until
it bottoms out on the
mounting boss.
If after changing the Temperature Sensor a diagnostic code is still indicated,
the G-II PCM is faulty. Go to G-II PCM replacement, page 4-38.
WARNING
NEVER remove coolant lines when
the engine/system is HOT – escaping
steam or scalding water could cause
serious personal injury. Loosen the
coolant line clamps slowly, allowing
the pressure to escape before
removing completely.
NOTICE
All plugs/harnesses must be rein-
stalled into the G-II Proheat Control
Module (G-II PCM) before heater
goes back into service.
Figure 4-30: Temperature Sensor.
DUAL MODE TEMP
SENSOR
INLET
OUTLET
4-28 PROHEAT M-SERIES G-II PCM SERVICE MANUAL