Checking Communication With MCC Control Module
Checking communication with MCC control module
Checking control module communication
- Ignition on.
- Wait approximately 5 seconds. It takes approximately 5 seconds before the control module can update the different functions.
Check the control module is functioning by checking control of damper motor recirculation or damper motor air distribution. Listen to the motor or visually inspect the damper motor and its linkage.
To access/replace the damper motor, refer to Replacing damper motors Removal and Replacement (Damper motor switch air distribution) Replacing damper motors Removal and Replacement (Damper motor air distribution)
Check that the REC button LED is functioning by engaging and disengaging the REC function. If the control module controls the motors correctly and the LED is OK this indicates that the control module is functioning.
Is the control module functioning?
Yes - No Fault Found
No - Checking power supply and ground for MCC control module
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Checking power supply and ground for MCC control module
Check that fuses 31 and 7 are intact. If any fuses are blown, check the circuit after the fuse for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Hint: For further information about the circuit after the fuse, see Wiring Diagram.
Then replace the fuse.
Check MCC control module connector for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check power supply to MCC control module #B6 and #B17 for an open circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check ground lead between MCC control module #B16 and ground terminal for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Remedy as necessary
Other information:
- To access the control module, see Replacing or adjusting control cables / mechanical rear section and control panel / front section (Manual climate control / STANDARD) Service and Repair.
- To connect the breakout box, see Connection of breakout box MCC Connection of Breakout Box MCC.
Continue - Verification
DONE
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Verification
Hint: After carrying out the repair, check that the fault has been remedied as follows:
- Ignition on.
- Wait approximately 5 seconds. It takes approximately 5 seconds before the control module can update the different functions.
Check the control module is functioning by checking control of damper motor recirculation or damper motor air distribution. Listen to the motor or visually inspect the damper motor and its linkage.
To access/replace the damper motor, refer to Replacing damper motors Removal and Replacement (Damper motor switch air distribution) Replacing damper motors Removal and Replacement (Damper motor air distribution)
Check that the REC button LED is functioning by engaging and disengaging the REC function.
Is the control module functioning?
Yes - FAULT FOUND
No - Fault-tracing information
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 - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Checking control module communication
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