Overheat Diagnostic Code; Voltage Diagnostic Code - Proheat M80 Service Manual

CAUTION
Repeatedly resetting the PROHEAT
without resolving the Overheat
diagnostic code will damage the
heat exchanger.
VOLTAGE: Step 1
VOLTAGE: Step 2
PROHEAT M-SERIES SERVICE MANUAL
3.1.4

OVERHEAT Diagnostic Code

(4 Flashes) Indicates that the Temperature Sensor detected an inner heat exchanger
surface temperature of 230°F (110°C) within 60 seconds after entering
Cool Down.
Troubleshoot the Overheat diagnostic code based on:
1. Lack of coolant, air or flow problems in the coolant system.
Go to page 3-25, Steps 1 and 2.
2. Faulty Temperature Sensor.
3. Faulty PCM Temperature Sensor circuit.
To reset the PROHEAT, switch it off and then on again.
3.1.5

VOLTAGE Diagnostic Code

(5 Flashes) Indicates that the supply voltage to the PCM is outside the operating range.
Operating Range:
• 12 volt PROHEAT – 10 to 15 volts.
• 24 volt PROHEAT – 20 to 30 volts.
Troubleshoot the Voltage diagnostic code based on:
1. Low voltage.
• Voltage supply is below the rated requirement.
• Poor or faulty electrical connections.
• Voltage supply source is OK. Voltage drop due to high amperage load
while the PROHEAT is operating or trying to operate.
2. High voltage.
• Voltage supply is above the rated requirement while the vehicle
engine is running.
High Voltage – Check:
(5 Flashes) The vehicle charging system. Consult the OEM for service requirements.
Low Voltage – Check:
(5 Flashes) a) System voltage supply source.
b) Wiring harnesses and connection points.
Go to page 3-29.
Go to page 3-29.
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