OBD Guide
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B1946

Climate Control A/C Post Evaporator Sensor Circuit Failure

B1946 is an OBD-II diagnostic trouble code meaning: Climate Control A/C Post Evaporator Sensor Circuit Failure. Common causes: broken or damaged evaporator sensor harness wiring, oxidation or corrosion of sensor connector contacts. Estimated repair cost: $33–89.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$33–89 (est.)

Symptoms

  • Climate control fault lamp on the instrument panel
  • The air conditioner does not cool the air or does not work properly
  • The air conditioning compressor is constantly on or off
  • The air conditioning system goes into emergency mode
  • The climate control display shows an error code
  • Interior temperature is not properly controlled

Causes

  • Broken or damaged evaporator sensor harness wiring
  • Oxidation or corrosion of sensor connector contacts
  • Evaporator temperature sensor failure
  • Poor connection in the connector or broken wire
  • Short circuit in the sensor circuit
  • Malfunction of the climate control unit
  • Lack of power or ground in the sensor circuit
  • Problem with sensor control relay circuits

How to Fix

  1. Connect a diagnostic scanner and clarify the exact description of the malfunction in the system
  2. Visually inspect the harness wiring and sensor connectors for damage, oxidation, or looseness.
  3. Disconnect the sensor connector and clean the contacts from corrosion with alcohol or coupling fluid.
  4. Measure the resistance of the sensor with a multimeter (usually 2-10 kOhm depending on the model)
  5. Check the supply voltage at the sensor connector (usually 5V or 12V)
  6. Check the integrity of the harness wires between the sensor and the control unit
  7. If necessary, replace the evaporator sensor with a new one
  8. Reconnect the connector, make sure the connection is tight
  9. Clear error codes and test drive to check
  10. If the error persists, contact a specialist to check the control unit

Related codes

B1947B1945P0534P0535P0488

FAQ

What does the B1946 code mean?

B1946 is an OBD-II diagnostic trouble code that indicates: Climate Control A/C Post Evaporator Sensor Circuit Failure

What causes a B1946 error code?

The most common causes of B1946 include: Broken or damaged evaporator sensor harness wiring; Oxidation or corrosion of sensor connector contacts; Evaporator temperature sensor failure; Poor connection in the connector or broken wire.

How do I fix a B1946 diagnostic trouble code?

To fix B1946: Connect a diagnostic scanner and clarify the exact description of the malfunction in the system. Visually inspect the harness wiring and sensor connectors for damage, oxidation, or looseness.. Disconnect the sensor connector and clean the contacts from corrosion with alcohol or coupling fluid.. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1946?

Do not drive — repair immediately

How much does it cost to fix B1946?

The estimated repair cost for B1946 is $33–89. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat