Too Many Unsuccessful Attempts
Too many unsuccessful attempts
Checking quantity of fuel and voltage
- If the quantity of fuel in the fuel tank is below 6 liters the heater is not permitted to start. If the battery voltage is poor the heater is not permitted to start. The control module interprets 3 or more failed start attempts as a fault in the heater. The heater cannot then be started until the diagnostic trouble codes (DTCs) have been erased
- Ignition on.
Note! The heater must be switched off when reading off!
Read off the values.
The fuel level status must be OK and the voltage to the heater must be normal.
Other information:
- For a description of parameters, see Description of parameters Description of Parameters.
Was a fault detected?
Yes - Verification
No - Checking the fuel lines
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Checking the fuel lines
Warning! Use protective gloves and protective goggles due to the risk of fuel spillage.
- To expose the heater and access the fuel lines, see Engine coolant heater, replacing Engine Coolant Heater, Replacing.
Check the fuel lines for damage and leaks between their connection point to the engine fuel system and the heater via the fuel pump (FP).
Check the fuel lines for blockages.
Was a fault detected?
Yes - Verification
No - Checking components
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Checking components
Warning! Use protective gloves and protective goggles due to the risk of fuel spillage.
- Ignition on.
Note! It is important that only the ignition is on in order for the heater to start.
- Activate the heater.
A buzzing sound must be heard from the heater
Check whether the fuel pump is operating. The pump should make a ticking sound.
If the pump does not operate replace the fuel pump according to Fuel pump auxiliary heater, replacing Service and Repair.
Other information:
- For a description of parameters, see Description of parameters Description of Parameters
- For a description of activations, see Activating components/functions Activating Components/Functions.
Did the heater operate?
Yes - Checking the nozzle pipe
No - Verification
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Checking the nozzle pipe
- Remove the heater. See Engine coolant heater, replacing Engine Coolant Heater, Replacing
- Disconnect the nozzle pipe according to Fuel injection nozzle / fan motor / pressure equalizer, replacing Fuel Injection Nozzle / Fan Motor / Pressure Equalizer, Replacing.
Check that the nozzle pipe is OK and that it is not blocked.
Remedy as necessary.
Was a fault detected?
Yes - Verification
No - Checking the intake air flow
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Checking the intake air flow
- Remove the heater. See Engine coolant heater, replacing Engine Coolant Heater, Replacing.
Check that the air flow through the heater is free (that the air intake and exhaust are not blocked).
Remedy as necessary.
Was a fault detected?
Yes - Verification
No - Checking the flame sensor
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Checking the flame sensor
Check that the flame sensor is not clogged with soot.
Remedy as necessary.
Other information:
- To access or replace the flame sensor, see Overheat protection thermostat / flame sensor / engine coolant temperature sensor, replacing Service and Repair.
Was a fault detected?
Yes - Verification
No - Checking components and wiring
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Checking components and wiring
Check the cable between control module terminal #4 and the ground terminal for the flame sensor. Check for an open-circuit.
Hint: It is difficult to differentiate between the flame sensor cables so take readings between control module terminal #4 and both flame sensor cables.
Check the cable between control module terminal #8 and the positive terminal for the flame sensor. Check for an open-circuit. Check for a short-circuit to supply voltage.
Hint: It is difficult to differentiate between the cables to the flame sensor. Take readings on the cables one at a time and see if a relevant value was obtained from either of them.
If no fault is found in the connectors or cables, try a new flame sensor.
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 flame sensor, see Overheat protection thermostat / flame sensor / engine coolant temperature sensor, replacing Service and Repair
- For other values, see Signal specification Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals.
Continue - Verification
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Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reinstall the connectors, components etc.
- Ignition on.
Erase diagnostic trouble codes (DTCs).
Note! Diagnostic trouble codes (DTCs) must be erased to start the heater. Before erasing diagnostic trouble codes (DTCs) all indicated faults must be corrected.
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Verification, continued
- Ignition off
- Reinstall the connectors, components etc.
- Ignition on.
Note! It is important that only the ignition is on in order for the heater to start.
- Activate the heater.
A buzzing sound should be heard from the heater.
Hint: After repair, the voltage of the flame sensor can be checked. The voltage should be a maximum of 1.0 V.
Check the function of the heater. See Engine coolant heater, test running Engine Coolant Heater, Test Running.
Other information:
- For a description of parameters, see Description of parameters Description of Parameters
- For a description of activations, see Activating components/functions Activating Components/Functions.
Does the heater operate?
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 quantity of fuel and voltage
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