Description:

The error code ETC 001079.03 is triggered when the voltage measured at the positive lead (lead 2093) of the power supply to the 5-volt components (refrigerant pressure sensor B130, heater valve B131, and motor for adjusting the air distribution flaps B132) exceeds 5 volts. This indicates that the circuit is shorted to a positive supply lead or there is an internal interruption at the control unit.

Reaction:

When this fault is detected, the control unit may disable or limit the operation of the 5-volt components to prevent damage due to overvoltage. This can result in the malfunction of the refrigerant pressure sensor, heater valve, and air distribution flap motor.

Recommendations:

Inspect Electrical Circuits:

• Check for Shorts to Positive Supply: Inspect the wiring and connectors for signs of short circuits to the positive supply lead. Look for damaged insulation or exposed wires.
• Measure Voltage: Use a multimeter to measure the voltage at the positive lead (lead 2093) to ensure it is within the specified range.

Test and Replace Components:

• Test 5-Volt Components: Verify the operation of the refrigerant pressure sensor B130, heater valve B131, and motor B132. Replace any components that are found to be malfunctioning due to overvoltage.
• Inspect Control Unit: Ensure that the control unit is functioning correctly. Replace the control unit if it is found to be faulty.

Repair or Replace Wiring:

• Fix Damaged Wiring: Repair or replace any damaged or shorted wiring in the 5-volt power supply circuit. Ensure all connections are secure and properly insulated.

Note:

Regular maintenance and inspection of the electrical system can help prevent issues related to overvoltage. Ensuring proper routing and securing of wires can reduce the risk of shorts and enhance system reliability.