Signal Too High
Signal too high
Checking the blower fan
- Ignition on.
Check that the blower fan functions by turning the blower fan knob to maximum fan speed.
Is the blower fan working?
Yes - Checking the connectors and cables
No - Checking the connectors
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Checking the connectors
- Ignition off
- Check the connectors on the climate control module (CCM) (terminals #A2, #A3) and the power unit. Check for contact resistance and oxidation. In particular, check for any damage
- Reinstall the components, reconnect the connectors etc.
- Ignition on.
Note! If the battery voltage has been interrupted, the blower fan speed must be calibrated. First turn the blower fan speed control to maximum speed and then to minimum speed.
Check that the blower fan motor functions: Turn the blower fan speed switch.
If the blower fan is now working the cause of the fault was loose connections in the connectors.
Other information:
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- To access or replace the control module, see Comfort panel (including climate control module, CCM), replacing Service and Repair
- To access or replace the power unit, see Blower fan motor / power unit, replacing, L.H.D, R.H.D Blower Fan Motor/Power Unit (Blower Motor Resistor), Replacing.
Is the blower fan motor functioning?
Yes - Fault Found
No - Checking components and wiring
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Checking components and wiring
Caution! The blower fan motor power unit is very sensitive to short-circuits and excess current. Do not damage the power unit when taking readings.Take readings with the power unit connector disconnected when checking the wiring.
Checking the engine cooling fan (FC) motor
Check that the blower fan rotor can rotate freely in the climate control system and that nothing is blocking it. Check by hand whether the blower fan rotor can rotate freely.
Checking the wiring
Check the ground lead between the power unit terminal #A4 and the ground terminal. Check for a short-circuit to supply voltage.
Check the control signal cable between control module terminal #A3 and power unit terminal #A1. Check for an open-circuit. Check for a short-circuit to ground.
Check the diagnostic signal cable between control module terminal #A2 and power unit terminal #A3. Check for a short-circuit to supply voltage.
Note! If the battery voltage has been interrupted, the blower fan speed must be calibrated. First turn the blower fan speed control to maximum speed and then to minimum speed.
Remedy as necessary.
Other information:
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- To access or replace the control module, see Comfort panel (including climate control module, CCM), replacing Service and Repair
- To access or replace the power unit, see Blower fan motor / power unit, replacing, L.H.D, R.H.D Blower Fan Motor/Power Unit (Blower Motor Resistor), Replacing
- For other values, see Signal description, climate control module (CCM), Connector A Signal Description, Climate Control Module (CCM), Connector A
- For further information about the fuses, relays and ground terminals, see the relevant Wiring Diagram.
Continue - Verification
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Checking the connectors and cables
Caution! The blower fan motor power unit is very sensitive to short-circuits and excess current. Do not damage the power unit when taking readings.Take readings with the power unit connector disconnected when checking the wiring.
Check the connectors on the control module (terminals #A2, #A3) and the power unit. Check for contact resistance and oxidation. Check for loose connections.
Check the ground lead between the power unit terminal #A4 and the ground terminal. Check for an intermittent short-circuit to supply voltage.
Check the control signal cable between the control module terminal #A3 and power unit terminal #A1. Check for an intermittent open-circuit. Check for an intermittent short-circuit to ground.
Check the diagnostic signal cable between control module terminal #A2 and power unit terminal #A3. Check for an intermittent short-circuit to supply voltage.
Note! If the battery voltage has been interrupted, the blower fan speed must be calibrated. First turn the blower fan speed control to maximum speed and then to minimum speed.
Remedy as necessary.
Other information:
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- To access or replace the control module, see Climate control module (CCM), replacing Service and Repair
- To access or replace the power unit, see Blower fan motor / power unit, replacing Blower Fan Motor/Power Unit (Blower Motor Resistor), Replacing
- For other values, see Signal specification Pinout Values and Diagnostic Parameters
- Checking wiring and terminals Checking Wiring And Terminals.
Continue - Fault-tracing information
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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 the connectors, install the components, etc.
- Ignition on.
- Read the diagnostic trouble codes.
If the status of the diagnostic trouble code has changed to an intermittent fault this indicates that the fault has been rectified.
Has the status of the diagnostic trouble code changed?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFICATION FAILED - Fault-tracing information
VERIFIED - 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 - No Fault Found
Attempt New Test - Checking the blower fan
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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
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Attempt New Test - Checking the blower fan
FAULT FOUND - DONE
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