B1946 OBD-II Trouble Code: Climate Control A/C Post Evaporator Sensor Circuit Failure

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the B1946 code

B1946 is a diagnostic trouble code (DTC) for "Climate Control A/C Post Evaporator Sensor Circuit Failure". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE B1946 DIAGNOSTIC Get a fair and transparent estimate upfront

B1946 code definition

The B1946 code is a manufacturer specific body code related to the climate control system. In this case, the engine control module (ECM) has detected a failure in the evaporator temperature sensor for the climate control system or A/C.

What the B1946 code means

A code B1946 will be stored when the ECM detects a voltage signal from the post evaporator sensor that is signalling a failure (the signal should be approximately 5 volts depending on vehicle make and model).

Under normal operation, the LH and RH discharge temperature sensors receive a ground from the Dual Automatic Temperature Control (DATC) module. The evaporator discharge temperature sensor receives a ground from the DATC module. A 5-volt reference voltage is supplied to the LH and RH discharge temperature sensors from the DATC module. A 5- volt reference voltage is supplied to the evaporator discharge temperature sensor from the DATC module.

What causes the B1946 code?

Several problems may cause a B1946 code including:

  • Malfunctioning, damaged, or defective evaporator temperature sensor
  • Damaged or defective climate control unit
  • An open or shorted circuit in the wiring harness between the climate control unit and evaporator temperature sensor

What are the symptoms of the B1946 code?

Symptoms of a B1946 code may include:

  • Check engine or warning light may illuminate
  • Climate control or A/C may not blow cold air
  • Climate control or A/C may not work at all
  • There may be no symptoms other than a stored B1946 code

How does a mechanic diagnose the B1946 code?

A mechanic may use several methods to diagnose a B1946 trouble code, including:

  • Utilize an OBD-II scanner to check for a stored B1946 trouble code
  • Visually inspect wiring and electrical components related to the evaporator temperature sensor for signs of damage
  • Visually inspect the evaporator temperature sensor for signs of damage
  • Test the resistance on the evaporator temperature sensor (resistance should be measured compared with temperature ranges)
  • Check the DATC sensor output voltage (it should be between 4.7 and 5.1 volts)
  • Disconnect climate control unit and evaporator temperature sensor connector and check for an open circuit that has less than 5 ohms resistance
  • Check return circuit for an open or short circuit
  • Check reference circuit for a short to ground
  • Check reference circuits for a short to the return circuits

How serious is the B1946 code?

Because a vehicle’s safe driving operation most likely will not be impacted due to faults that store a B1946 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 B1946 code?

Several repairs can fix a B1946 trouble code and include:

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.

In addition, note that the evaporator core, driver side heater core, and passenger side heater core discharge air temperature sensors have the same diagnostic procedure.

Need help with a B1946 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.

trouble codes
OBD-II
B1946

No more waiting rooms! Our mechanics will come to you to diagnose and fix the B1946 code.

SCHEDULE B1946 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,079

Rating Summary
4,679
195
48
27
130
4,679
195
48
27
130

Robert

39 years of experience
15 reviews
Robert
39 years of experience
Jaguar S-Type - Check Engine Light is on - Scottsdale, Arizona
Bob is very thorough and an all-around professional. I'll be booking his service for both my cars as often as work is needed.

Eduardo

18 years of experience
353 reviews
Eduardo
18 years of experience
Dodge Dakota - Check Engine Light is on - Stafford, Texas
Great guy very knowledgeable and very professional one of the best mechanics I've ever met. He explained what was going on and let me know my options. Will be asking for him again!

Michael

15 years of experience
524 reviews
Michael
15 years of experience
Toyota Corolla - Check Engine Light is on - Atlanta, Georgia
Michael was a great mechanic, and nice guy. He was knowledgeable and offered examples of my current problems while also sharing solutions.

Juan

8 years of experience
53 reviews
Juan
8 years of experience
Honda Pilot - Check Engine Light is on - Chapel Hill, North Carolina
Great job, explained the situation to me and told me to try to get the dealer to repair it under warranty. I certainly will but if they give me a song and dance I will be back and have Juan do it in a heartbeat. I’m well pleased.


More related articles

P0130 OBD-II Trouble Code: 02 Sensor Circuit Malfunction (Bank I Sensor 1)
P0130 code definition The P0130 code is associated with the bank 1, sensor 1, oxygen sensor. Your vehicle may have anywhere up...
B1979 OBD-II Trouble Code: Passenger Seat Rearward Switch Circuit Short to Battery
B1979 means there is an issue with the passenger seat rearward switch circuit error, likely due to damaged electrical components or a bad switch.
P2086 OBD-II Trouble Code: Exhaust Gas Temperature Sensor Circuit Range/Performance Bank 2 Sensor 2
What What the P2086 code means? P2086 is an OBD-II generic code for the exhaust gas temperature sensor circuit signal is out of range for bank 2 Sensor 2 to the engine control module (ECM). This means the sensor signal...

Related questions

Codes showing: P0171, P0420, P0174

Hello. These diagnostic trouble codes are an indication that there could be a problem with the oxygen sensor or that there is a vacuum leak. It is possible that the vacuum leak is located in the intake manifold. These codes...

My problem is Check Engine Light on. Cruise control does not work, loses power on hills, as if it does not want to pull hill.

Hi there. From the description you have provided, there is several possibilities for your vehicle's drivability problems. Your vehicle's Check Engine Light may help diagnose the lack of power and inoperative cruise control. Accessing the vehicle's computer for codes stored,...

P0420 - CATALYST B1 DETERIORATION

Hello - it is possible the 2 problems are related, but likely only over a long period of time. The P0420 code is a "low efficiency catalytic converter" for Bank2 - which include cylinder 1. And yes, that warning is...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com