Signal Too Low
Signal too low
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 an intermittent short-circuit to ground.
Are the temperatures correct?
Yes - Checking the wiring
No - Checking resistance values
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Checking resistance values
- Ignition off.
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.
Measure the resistance between climate control module (CCM) connector terminals #B1(#1) and #B15 (#15). This value must correspond with the resistance of the evaporator temperature sensor.
Other information:
- To access or replace the control module, see Climate control module (CCM), replacing Service and Repair
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- To access or replace the evaporator temperature sensor, see Temperature sensor evaporator, replacing Service and Repair
- For the resistance values, see Component resistance values [1][2]Electrical Specifications
- For other values, see Signal specification Pinout Values and Diagnostic Parameters
- Checking wiring and terminals Checking Wiring And Terminals.
Is the resistance correct?
Yes - Checking the wiring
No - Checking the evaporator temperature sensor
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Checking the wiring
- Ignition off.
Check the signal cable between climate control module (CCM) terminal #B1 (#1) and evaporator temperature sensor #2 (#27). Check for a short-circuit to ground.
Remedy as necessary.
Other information:
- To access or replace the control module, see Climate control module (CCM), replacing Service and Repair
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- To access or replace the evaporator temperature sensor, see Temperature sensor evaporator, replacing Service and Repair
- For other values, see Signal specification Pinout Values and Diagnostic Parameters
- Checking wiring and terminals Checking Wiring And Terminals.
Continue - Verification
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Checking the evaporator temperature sensor
Check the evaporator temperature sensor by measuring the resistance at the sensor connector between terminals #2 (#27) and #3 (#28).
The resistance must correspond to the value in the table.
Replace the evaporator temperature sensor if the resistance is not correct.
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
- To access or replace the evaporator temperature sensor, see Temperature sensor, evaporator, replacing Service and Repair
- For resistance values, see Component resistance values [1][2]Electrical Specifications.
Continue - Verification
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Checking the wiring
Check the signal cable between climate control module (CCM) terminal #B1 (#1) and evaporator temperature sensor terminal #2 (#27). Check for an intermittent short-circuit to ground.
Remedy as necessary.
Other information:
- To access or replace the control module, see Climate control module (CCM), replacing Service and Repair
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- To access or replace the evaporator temperature sensor, see Temperature sensor evaporator, replacing Service and Repair
- For other values, see Signal specification Pinout Values and Diagnostic Parameters
- Checking wiring and terminals Checking Wiring And Terminals.
Continue - Verification
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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.
Check evaporator temperature.
The value should be between -40 °C and +85 °C (-40 °F and +185 °F).
Start engine and switch on air-conditioning unit.
Check that the value changes and remains between the given minimum and maximum values.
Does the value change?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFIED - Fault Found
VERIFICATION FAILED - Information
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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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Attempt New Test - Checking the evaporator temperature
FAULT-TRACING FAILED - No Fault Found
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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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FAULT FOUND - Fault Found
Attempt New Test - Checking the evaporator temperature
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