B1947 – Climate Control A/C Post Evaporator Sensor Circuit Short To Ground

The ODBII code B1947 indicates a short circuit to ground in the climate control A/C post evaporator sensor circuit, which can affect the air conditioning system’s performance and temperature regulation.

The severity of ODBII code B1947 is moderate.

Common Causes For: B1946 Climate Control A/C Post Evaporator Sensor Circuit Failure

• Damaged wiring or connectors
• Shorted sensor
• Faulty evaporator temperature sensor
• Corroded terminals
• Grounding issues in the circuit
• Malfunctioning climate control module

Common misdiagnosis for B1947 Climate Control A/C Post Evaporator Sensor Circuit Short To Ground

• Faulty A/C control module
• Defective evaporator temperature sensor
• Wiring issues or shorts in the harness
• Malfunctioning climate control unit
• Refrigerant level issues
• Faulty blower motor
• Incorrectly installed or damaged evaporator core
• Issues with the HVAC blend door actuator

Common Troubleshooting Steps

When dealing with OBD-II code B1947, which indicates a “Climate Control A/C Post Evaporator Sensor Circuit Short To Ground,” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• Understand the Code: B1947 typically relates to the A/C system’s post-evaporator temperature sensor. A short to ground means that the circuit is being unintentionally connected to the ground, which can cause incorrect readings or system malfunctions.
• Visual Inspection: **Wiring and Connectors: Inspect the wiring harness and connectors associated with the post-evaporator sensor. Look for signs of damage, fraying, corrosion, or loose connections.
• **Sensor Condition: Check the condition of the post-evaporator sensor itself. Ensure it is properly mounted and not physically damaged.
• Check for Shorts: **Multimeter Testing: Use a multimeter to check for continuity in the wiring. Disconnect the sensor and measure the resistance between the sensor wire and ground. A low resistance reading indicates a short to ground.
• **Inspect Ground Points: Check the ground points in the circuit to ensure they are clean and secure.
• Test the Sensor: **Sensor Resistance: With the sensor disconnected, measure its resistance. Compare the reading to the manufacturer’s specifications. If it is out of range, the sensor may need to be replaced.
• **Functionality Test: If possible, test the sensor in a controlled environment to see if it responds correctly to temperature changes.
• Check the A/C Control Module: **Module Functionality: If the wiring and sensor are in good condition, the issue may lie within the A/C control module. Check for any software updates or known issues with the module.
• **Scan Tool Data: Use an OBD-II scanner to monitor live data from the A/C system. Look for any irregularities in the readings from the post-evaporator sensor.
• Inspect Related Components: **Other Sensors: Check other related sensors and components in the A/C system, as issues with one part can sometimes affect others.
• **Fuses and Relays: Inspect fuses and relays related to the climate control system to ensure they are functioning properly.
• Clear Codes and Test Drive: After performing repairs or replacements, clear the trouble codes using an OBD-II scanner. Take the vehicle for a test drive to see if the code reappears.
• Consult Technical Resources: If the issue persists, consult the vehicle’s service manual or technical resources for specific diagnostic procedures related to the B1947 code for your make and model.
• Professional Help: If you are unable to resolve the issue after these steps, consider seeking help from a professional mechanic or an automotive technician who specializes in climate control systems. By following these steps, you should be able to identify and address the cause of the B1947 code effectively.