Signal Too High
Signal too high
Checking heater function
- Start engine.
Note! When the heater unit also functions as a parking heater turning the ignition on is enough.
- Activate heater.
Check heater function according to Test running the additional heater / parking heater Initial Inspection and Diagnostic Overview.
Does the heater function?
Yes - Intermittent fault
No - Start attempts
Fault-trace
-------------------------------------------------
Intermittent fault
Check control module connector for contact resistance and oxidation according to Checking wiring and terminals. Intermittent faults Checking Wiring And Terminals. Intermittent Faults.
Check flame sensor circuit for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring And Terminals. Intermittent Faults.
Check cable between control module #8 and flame sensor signal terminal for an intermittent short-circuit to supply voltage according to Checking wiring and terminals. Intermittent faults Checking Wiring And Terminals. Intermittent Faults.
Remedy as necessary.
Other information:
- To access the control module/connect breakout box
- To access/replace the flame sensor see Overheating protection thermostat, flame sensor and Coolant temperature sensor, replace Replacing Overheat Protection, Thermostat Flame Sensor And Coolant Temperature Sensor.
- For other values, see Signal specification Additional heater 912-D/B Signal Specification Additional Heater 912-D/B.
Select Continue.
Continue - Fault-tracing information
DONE
-------------------------------------------------
Fault-tracing information
Information
Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.
It is possible to view the information again, or leave fault-tracing for this diagnostic trouble code (DTC).
Do you want to view the information again?
Yes - Attempt New Test
No - FAULT FOUND
------------------------
Attempt New Test - Checking heater function
DONE - DONE
FAULT FOUND - FAULT FOUND
-------------------------------------------------
Start attempts
Too many unsuccessful
Selecting Parking heater or Additional heater
Fault-tracing for this diagnostic trouble code (DTC) can differ depending whether the heater is functioning as an Additional Heater or as a Parking heater as well.
The major difference between the two methods is that the Additional heater has the fuel pump (FP) installed at the heater and the fuel lines are connected to the return side on the engine fuel system at the engine. If the installation is used as a parking heater the fuel pump is installed at the fuel tank and the fuel lines are routed from the fuel tank to the heater, there is also a Timer installed in the passenger compartment.
Is the heater also used as a parking heater?
Yes - Checking fuel lines, parking heater
No - Checking fuel lines, additional heater
------------------------
Checking fuel lines, additional heater
Warning! Use protective gloves and protective goggles to reduce risk from fuel spillage.
- To expose the heater and get access to the fuel lines refer to Replacing heat exchanger Service and Repair.
Check fuel lines between connection point at the engine fuel system and heater via fuel pump (FP), for damage and leakage.
Also check fuel lines for blockage.
Remedy as necessary.
Was a fault detected?
Yes - Verification
No - Checking the fuel pump (FP)
------------------------
Checking fuel lines, parking heater
Warning! Use protective gloves and protective goggles to reduce risk from fuel spillage.
- To expose the heater and get access to the fuel lines refer to Replacing heat exchanger Service and Repair.
Check fuel lines between fuel tank and heater via the fuel pump, for damage and leaks.
Also check fuel lines for blockage.
Remedy as necessary.
Was a fault detected?
Yes - Verification
No - Checking the fuel pump (FP)
------------------------
Checking the fuel pump (FP)
Warning! Use protective gloves and protective goggles to reduce risk from fuel spillage.
Hint: The fuel pump (FP) is installed in the fuel tank instead of on the heater when the Additional Heater is also used as a parking heater.
- Ignition on.
- Activate heater in order to start the pump. The pump does not start directly after starting the heater.
Check if the fuel pump is operating, a "ticking" sound should be audible.
If the pump is not working, install a new fuel pump.
Is the pump operating?
Yes - Checking nozzle pipe
No - Verification
------------------------
Checking nozzle pipe
- Remove heater according to Replacing heat exchanger Service and Repair.
- Disconnect nozzle pipe according to Replacing fuel injection nozzle, fan motor and nozzle pipe Service and Repair.
Check that the nozzle pipe seems OK and that it is not blocked.
Remedy as necessary.
Was a fault detected?
Yes - Verification
No - Checking intake air flow
------------------------
Checking intake air flow
- Remove heater according to Replacing heat exchanger Service and Repair.
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 flame sensor
------------------------
Checking flame sensor
Check if the flame sensor is clogged with soot.
Remedy as necessary.
Other information:
- To access/replace the flame sensor see Overheating protection thermostat, flame sensor and Coolant temperature sensor, replace Replacing Overheat Protection, Thermostat Flame Sensor And Coolant Temperature Sensor.
Was a fault detected?
Yes - Verification
No - Checking component and cables
------------------------
Checking component and cables
Check cable between control module #4 and flame trap ground terminal for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault.
Hint: Because it is difficult to separate the flame sensor cables measure between control module #4 and both flame sensor cables.
Check cable between control module #8 and flame sensor signal terminal for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault and a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault.
Hint: Because it is difficult to separate the flame sensor cables try to measure one flame sensor cable at a time and see if there is a relevant value on either of them.
If no fault is found in the connectors or cables, try a new flame sensor.
Note! Diagnostic trouble code (DTC) HEA-142 outside temperature sensor signal and/or HEA-801 Coolant temperature sensor signal can be stored if there is a fault in the ground lead
Remedy as necessary.
Other information:
- To access the control module/connect breakout box
- To access/replace the flame sensor see Overheating protection thermostat, flame sensor and Coolant temperature sensor, replace Replacing Overheat Protection, Thermostat Flame Sensor And Coolant Temperature Sensor.
- With ignition on and flame sensor signal cable cut the voltage between flame sensor signal cable (engine control module (ECM) side) and ground should be approximately 5 V.
- For other values, see Signal specification Additional heater 912-D/B Signal Specification Additional Heater 912-D/B.
Select Continue.
Continue - Verification
------------------------
Verification
Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reinstall the connectors, components etc.
- Ignition on (with additional heater start the engine).
Note! On cars where the heater functions as a parking heater there is no +15 voltage supply to the control module. The heater is activated using the timer stop and start buttons instead of VIDA vehicle communication. Individual components and functions cannot be activated when the +15 voltage supply is absent.
- Activate the heater.
Check the function of the heater according to Test running the additional heater / parking heater Initial Inspection and Diagnostic Overview.
Does the heater operate?
Yes - VERIFIED
No - VERIFICATION FAILEDPAPER
------------------------
VERIFICATION FAILED - Fault-tracing information
VERIFIED - FAULT FOUND
-------------------------------------------------
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
------------------------
FAULT-TRACING FAILED - FAULT-TRACING FAILED
Attempt New Test - Selecting Parking heater or Additional heater
-------------------------------------------------
No Fault Found - No Fault Found
FAULT-TRACING FAILED - FAULT-TRACING FAILED
FAULT FOUND - FAULT FOUND
-------------------------------------------------