The error code, ATC 001553.03, is triggered when the control unit measures a voltage exceeding 5 volts at the signal input for the fan speed control. This unusually high voltage typically indicates that the internal circuit of the control unit is either shorted to a power supply lead or is open. Such a condition can…

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The error code, ATC 001552.04, is triggered when the control unit measures 0 volts at the signal input for the temperature control. This absence of voltage generally indicates a short to ground within the internal circuit of the control unit. Such a fault can prevent the temperature control from functioning correctly, potentially leading to an…

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The error code, ATC 001552.03, is triggered when the control unit detects a voltage exceeding 5 volts at the signal input for the temperature control. This high voltage typically indicates that the internal circuit of the control unit is either shorted to a power supply lead or is open. Such an issue could impact the…

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The error code, ATC 001549.13, is triggered when the heater valve (B131) is found to have an invalid calibration or is not yet calibrated. This situation can lead to improper operation of the heater valve, affecting the heating system’s ability to accurately regulate the cabin temperature based on the control unit’s commands.

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The error code, ATC 001549.07, is triggered when the control unit receives a valid position signal from the heater valve potentiometer (B131), but the heater valve cannot be adjusted to its desired position via the motor’s connecting leads. This condition indicates a mechanical fault in the heater valve or an issue such as an open…

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The error code, ATC 001549.04, is triggered when the control unit detects abnormally low voltage at the motor connecting leads (2016 and/or 2027) for the heater valve (B131). This low voltage usually indicates that the circuit is grounded, which can impair the function of the heater valve’s adjusting motor, potentially leading to inadequate heating control…

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The error code, ATC 001549.03, is triggered when the control unit measures excessive voltage at the motor connecting leads (2016 and/or 2027) for the heater valve (B131). This high voltage typically indicates a short in the circuit, which can affect the operation of the heater valve’s adjusting motor. Such conditions can lead to malfunctioning or…

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The error code, ATC 001548.04, is triggered when the control unit measures 0 volts at the signal input for the outlet temperature sensor (B128, lead 2009). This absence of voltage usually indicates a short to ground within the circuit, which can disrupt the sensor’s ability to accurately measure and report the temperature, potentially leading to…

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The error code, ATC 001548.03, is triggered when the control unit detects a voltage exceeding 5 volts at the signal input for the outlet temperature sensor (B128, lead 2009). This high voltage condition typically indicates that the circuit is either shorted to a power supply lead or is open, which can result in incorrect temperature…

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The error code, ATC 001547.04, is triggered when the control unit measures 0 volts at the signal input for the evaporator core temperature sensor (B129, lead 2018). This absence of voltage typically indicates a short to ground in the circuit, which can prevent the sensor from functioning and lead to inaccurate or nonexistent temperature readings…

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The error code, ATC 001547.03, is triggered when the control unit measures a voltage exceeding 5 volts at the signal input for the evaporator core temperature sensor (B129, lead 2018). This unusually high voltage suggests that the circuit is either shorted to a supply lead or is open, which can lead to incorrect temperature readings…

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