Signal Too High / Signal Missing
Signal too high / Signal missing
Checking the evaporator temperature
- Ignition on.
Check that the evaporator temperature is within its permitted range. If the climate control system has not been running and the engine has cooled down, the temperature must be the same as the outside temperature.
If the temperature is now OK, the fault was caused by contact resistance or loose connections.
Read off the evaporator temperature by clicking on the VCT2000 symbol.
Are the temperatures correct?
Yes - Checking the connectors and wiring
No - Checking the component and wiring
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Checking the connectors and wiring
- Ignition off
- Disconnect the connector for the climate control module (CCM).
Check the signal cable between the climate control module (CCM) and the evaporator temperature sensor. Check for a short-circuit to supply voltage.
Take a reading on the connector for the climate control module (CCM) between terminals #5 (#29) and #16 (#40).
Check the ground lead between the climate control module (CCM) and the evaporator temperature sensor. Check for a short-circuit to supply voltage.
Take a reading on the connector for the climate control module (CCM) between terminals #14 (#38) and #16 (#40).
The voltage must be approximately 0 V.
Check the signal and ground cables between the climate control module (CCM) and the evaporator temperature sensor. Check for an intermittent open-circuit.
Take a reading between terminals #5 (#29) and #14 (#38) on the connector for the climate control module (CCM).
Check the connectors for contact resistance and oxidation.
Remedy as necessary.
Other information:
- For further information about the connectors, fuses and relays, see the Wiring Diagram
- Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- Signal description Signal Description, Climate Control Module (CCM)
- Component location Component Location, Climate Control Module (CCM)
- Climate control module (CCM) Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals
Continue - Checking the component and wiring
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Checking the component and wiring
- Ignition off
- Disconnect the connector for the climate control module (CCM).
Check the signal cable between the climate control module (CCM) and the evaporator temperature sensor. Check for a short-circuit to supply voltage.
Take a reading on the connector for the climate control module (CCM) between terminals #5 (#29) and #16 (#40).
Check the ground lead between the climate control module (CCM) and the evaporator temperature sensor. Check for a short-circuit to supply voltage.
Take a reading on the connector for the climate control module (CCM) between terminals #14 (#38) and #16 (#40).
The voltage must be approximately 0 V.
Check the signal and ground cables between the climate control module (CCM) and the evaporator temperature sensor. Check for an open-circuit.
Take a reading between terminals #5 (#29) and #14 (#38) on the connector for the climate control module (CCM).
The resistance must correspond to the resistance for the evaporator temperature sensor.
Check the connectors for contact resistance and oxidation.
Check that the climate control module (CCM) is receiving a correct value from the evaporator temperature sensor by measuring its resistance and comparing with the values in the table.
Remedy as necessary.
Other information:
- For further information about the connectors, fuses and relays, see the Wiring Diagram
- Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- Signal description Signal Description, Climate Control Module (CCM)
- Component location Component Location, Climate Control Module (CCM)
- Climate control module (CCM) Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals
- Component resistance values [1][2]Electrical Specifications
Continue - Verification
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reinstall the connectors, components etc.
- Ignition on.
Check the evaporator temperature sensor by clicking the VCT2000 symbol.
Check that the value from the evaporator temperature sensor corresponds to the ambient temperature.
Does the status change?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFIED - FAULT FOUND
VERIFICATION FAILED - Fault-tracing information
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Fault-tracing information
Attempt New Test - Checking the evaporator temperature
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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 evaporator temperature
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