AutoCodes – Generic – B1340

B1340 Code - Left Air Temperature Actuator

Quick Answer

The Instrument Panel Module (IPM) controls the HVAC door actuators to regulate the airflow through the Heating, Ventilation, and Air Conditioning (HVAC) system. Common causes include Faulty Left Air Temperature Actuator, Left Air Temperature Actuator harness is open or shorted, Left Air Temperature Actuator circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B1340 indicates Left Air Temperature Actuator.
Common causes: Common causes include Faulty Left Air Temperature Actuator, Left Air Temperature Actuator harness is open or shorted, Left Air Temperature Actuator circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 12,745

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 14, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1340 Description

The Instrument Panel Module (IPM) controls the HVAC door actuators to regulate the airflow through the Heating, Ventilation, and Air Conditioning (HVAC) system. Each actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Ignition 3 voltage, low reference, control, 5-volt reference and position signal circuits enable the actuator to operate. The control circuit uses either a 0, 2.5, or 5-volt signal to command the actuator movement. When the actuator is at rest, the control circuit value is 2.5 volts. A 0 or 5-volt control signal commands the actuator movement in opposite directions. When the actuator shaft rotates, the potentiometer's adjustable contact changes the door position signal between 0-5 volts. The IPM converts the voltage values to count values where one volt is approximately equal to 51 counts. The IPM uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted value, the control signal is changed to either 0 or 5 volts depending upon the direction that the actuator needs to rotate to reach the commanded value. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module changes the control signal to 2.5 volts.

OBDII Code B1340 - Left Air Temperature Actuator - AutoCodes.com — B1340 Code - Left Air Temperature Actuator

What does this mean?

What are the Possible Causes of the DTC B1340?

Faulty Left Air Temperature Actuator
Left Air Temperature Actuator harness is open or shorted
Left Air Temperature Actuator circuit poor electrical connection
Faulty Instrument Panel Module (IPM)

How to Fix the DTC B1340?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1340 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B1340 code?

Need more information on how to fix the B1340 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1340 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B1340 Buick — Left Air Temperature Actuator
B1340 Cadillac — Left Air Temperature Actuator
B1340 Chevrolet — Left Air Temperature Actuator
B1340 GMC — Left Air Temperature Actuator
B1340 Infiniti — Front Door Satellite Sensor Right Communication Error
B1340 Nissan — Front Door Satellite Sensor Right Communication Error
B1340 Pontiac — Left Air Temperature Actuator
B1340 Saturn — Left Air Temperature Actuator

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1340 Code

1. What are the common symptoms of OBDII code B1340 (Left Air Temperature Actuator)?

The common symptoms of B1340 may include inconsistent air temperature from the left side vents, the HVAC system blowing hot air on one side and cold air on the other, or the inability to adjust the left side temperature.

2. What are the possible causes of OBDII code B1340?

Possible causes of B1340 include a faulty left air temperature actuator, damaged wiring or connectors in the actuator circuit, or a malfunctioning HVAC control module.

3. How can I diagnose OBDII code B1340?

Diagnosing B1340 involves using a scan tool to retrieve the trouble code, checking the left air temperature actuator for proper operation, inspecting the wiring and connectors for any damage, and testing the HVAC control module for faults.

4. Can I drive my vehicle with OBDII code B1340?

While it may be possible to drive the vehicle with B1340, it is recommended to address the issue promptly to avoid further damage to the HVAC system and ensure comfort while driving.

5. How can I repair OBDII code B1340?

Repairing B1340 typically involves replacing the faulty left air temperature actuator, repairing any damaged wiring or connectors in the circuit, or reprogramming the HVAC control module if necessary.

6. Are there any DIY tips for fixing OBDII code B1340?

While diagnosing and repairing B1340 may require some technical knowledge, DIY enthusiasts can start by checking the actuator's electrical connections and fuses, ensuring they are secure and free of corrosion.

7. Is OBDII code B1340 a serious issue?

While B1340 may not affect the overall drivability of the vehicle, it can impact the comfort level inside the cabin. Addressing the issue in a timely manner is recommended to restore proper functionality to the HVAC system.

8. How common is OBDII code B1340 in vehicles?

B1340 related to the left air temperature actuator is a relatively common OBDII code found in vehicles equipped with dual-zone climate control systems.

9. Can extreme temperatures or weather conditions trigger OBDII code B1340?

Extreme temperatures or weather conditions may not directly trigger B1340, but they can exacerbate existing issues with the left air temperature actuator, leading to the code being stored in the system.

10. How much does it cost to repair OBDII code B1340 at a professional auto repair shop?

The cost of repairing B1340 can vary depending on the specific cause of the issue, the labor rates at the repair shop, and the cost of any replacement parts needed. It is advisable to get a diagnostic and repair estimate from a trusted auto repair facility.