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B1947 OBD-II Trouble Code: Climate Control A/C Post Evaporator Sensor Circuit Short To Ground

diagnostic check engine light

B1947 code definition

The B1947 code is a manufacturer-specific body code related to the climate control system. In this case, the engine control module (ECM) has detected a fault in the evaporator sensor for the climate control system or A/C.

What the B1947 code means

A code B1947 will be stored when the ECM detects a voltage signal from the post evaporator sensor that is signaling a short, or a signal other than approximately 5 volts (depending on vehicle make and model).

What causes the B1947 code?

Several problems may cause a B1947 code including:

  • Malfunctioning, damaged, or defective evaporator temperature sensor
  • Damaged or defective climate control unit
  • Open or short circuit in wiring harness between climate control unit and evaporator temperature sensor

What are the symptoms of the B1947 code?

Symptoms of a B1947 code may include: * Check engine or warning light may illuminate * Climate control or A/C may not work correctly * There may be no symptoms other than a stored B1947 code

How does a mechanic diagnose the B1947 code?

A mechanic may use several methods to diagnose a B1947 trouble code, including:

  • Utilize an OBD-II scanner to check for a stored B1947 trouble code
  • Visually inspect wiring and electrical components related to the evaporator temperature sensor for signs of damage
  • Inspect the evaporator temperature sensor
  • Disconnect climate control unit and evaporator temperature sensor connector and check for an open circuit in the wiring harness between the T-B and U-A terminals of the climate control unit and evaporator temperature sensor
  • Turn the ignition to the “on” position and using an ohmmeter to inspect voltage at Terminal T of the climate control unit terminal
  • Check if voltage is approximately 5 volts (may vary slightly depending on vehicle make and model, it is recommended to always consult your vehicle’s service manual)

How serious is the B1947 code?

Because a vehicle’s safe driving operation most likely will not be impacted due to faults that store a B1947 code, this code is not considered to be a serious code. When this code appears, it is recommended to take your vehicle to your local service center or mechanic for repair and diagnosis as soon as possible.

What repairs can fix the B1947 code?

Several repairs can fix a B1947 trouble code and include:

  • Repair or replace damaged or shorted electrical wiring and related components
  • Replace the damaged or defective evaporator temperature sensor
  • Repair any damaged or defective wiring harness between the T-B or U-A terminals
  • Replace damaged or defective climate control unit
  • Clear all codes, test-drive the vehicle, and rescan to see if any codes reappear

Additional information related to a B1947 code

It is always recommended to take all proper safety precautions when working with the electrical components of your vehicle and to carefully follow service instructions. With more complicated electrical repairs, it is recommended to seek assistance from a professional.

Need help with a B1947 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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