Signal Too High
Signal too high
Checking the water flow
Check if the lines to and from the heater are blocked, or if the heater is damaged causing the through flow to be restricted in some way.
Remedy as necessary.
Was a fault detected?
Yes - Verification
No - Checking the engine coolant temperature sensor
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Checking the engine coolant temperature sensor
- Start the engine
- Read off the coolant temperature in the heater.
Check that the engine coolant temperature (ECT) reading is correct. Compare with the actual coolant temperature of the engine.
Is the temperature reading OK?
Yes - Checking components and wiring
No - Checking components and wiring
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Checking components and wiring
Check the resistance of the engine coolant temperature sensor. For the resistance values, see Components resistance values Electronic. Auxiliary Heater.
Remedy as necessary.
Other information:
- To access or replace the engine coolant temperature sensor, see Overheat protection thermostat / flame sensor / engine coolant temperature sensor, replacing Service and Repair
- For other values, see Signal specification Signal Specification.
Continue - Verification
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Checking components and wiring
Check the fuel pump (FP) and the control module connectors. Check for contact resistance and oxidation.
Check the cable between control module terminal #13 and fuel pump (FP) terminal 1. Check for an intermittent open-circuit.
Check the cable between control module terminal #11 and fuel pump (FP) terminal 2. Check for an intermittent open-circuit.
Note! Diagnostic trouble code (DTC) CEM-5F3B Water pump, signal and / or diagnostic trouble code (DTC) CEM-5F3D Combustion fan, signal may be stored in the event of a fault in the power cable.
Remedy as necessary.
Other information:
- To access the control module or connect the breakout box, see Connecting the breakout box Connecting the Breakout Box
- To access or replace the fuel pump (FP), see Fuel pump auxiliary heater, replacing Service and Repair
- To access or replace the overheat protection thermostat, see Overheat protection thermostat / flame sensor / engine coolant temperature sensor, replacing Service and Repair
- Checking wiring and terminals Checking Wiring And Terminals
Continue - Verification
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Verification
Verification
Verification
Hint: After the repair it is necessary to check that the fault has been rectified.
- Ignition off.
- Connect connector, install components etc.
- Ignition on.
Note! It is important that only the ignition is on for the heater to start up.
- Activate the heater.
A buzzing sound should be heard from the heater.
Check the function of the heater as described in Engine coolant heater, test running Engine Coolant Heater, Test Running.
Additional information:
- For a description of the parameters, see Description of parameters Description of Parameters.
- For a description of activations, see Activating components/functions Activating Components/Functions.
Does the heater work?
Yes - VERIFIED
No - VERIFICATION FAILEDPAPER
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VERIFICATION FAILED - Fault-tracing information
VERIFIED - Fault Found
PAPER - No Fault Found
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Fault-tracing information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - FAULT-TRACING FAILED
No - Attempt New Test
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FAULT-TRACING FAILED - FAULT-TRACING FAILED
Attempt New Test - Checking the water flow
FAULT FOUND - Fault Found
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