AutoCodes – GMC – B1340 GMC

B1340 GMC 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 GMC 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 718

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

What does this mean?

What are the Possible Causes of the DTC B1340 GMC?

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 GMC?

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 GMC 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.

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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 GMC Code

1. What are common symptoms of OBDII code B1340 GMC related to the Left Air Temperature Actuator?

The common symptoms include inconsistent or incorrect air temperature output from the left side vents, lack of response to temperature adjustments, and potential issues with the vehicle's HVAC system.

2. What are the possible causes of OBDII code B1340 GMC for the Left Air Temperature Actuator?

The code B1340 GMC is typically triggered by a faulty left air temperature actuator, wiring issues, a malfunctioning HVAC control module, or a problem with the vehicle's climate control system.

3. How can I diagnose the cause of OBDII code B1340 GMC for the Left Air Temperature Actuator?

Diagnosis involves using a scan tool to retrieve the specific trouble code, inspecting the left air temperature actuator for proper function, checking the wiring connections for any damage, and testing the HVAC control module for faults.

4. Is it safe to continue driving with OBDII code B1340 GMC related to the Left Air Temperature Actuator?

While the vehicle may still be operable with this code, it is recommended to address the issue promptly to avoid potential discomfort due to incorrect temperature output and prevent further damage to the HVAC system.

5. Can I repair OBDII code B1340 GMC for the Left Air Temperature Actuator myself?

Depending on your experience level, you may be able to replace the left air temperature actuator or address wiring issues yourself. However, diagnosing and repairing problems with the HVAC control module or climate control system may require professional assistance.

6. What are some tips for preventing OBDII code B1340 GMC related to the Left Air Temperature Actuator?

Regularly maintaining your vehicle's HVAC system, checking for any unusual temperature fluctuations, and addressing any issues promptly can help prevent the occurrence of this trouble code.

7. How much does it typically cost to repair OBDII code B1340 GMC for the Left Air Temperature Actuator?

The cost of repairing this code can vary depending on the specific cause of the issue, the labor rates in your area, and whether you choose to address the problem yourself or take your vehicle to a professional mechanic.

8. Can a faulty left air temperature actuator cause other OBDII codes to appear?

Yes, a malfunctioning left air temperature actuator can potentially trigger other OBDII trouble codes related to the HVAC system or climate control, so it's essential to address the root cause promptly.

9. What are the long-term implications of ignoring OBDII code B1340 GMC related to the Left Air Temperature Actuator?

Ignoring this code can lead to continued discomfort while driving, potential strain on the vehicle's HVAC system, and the risk of additional components being affected if the underlying issue is not resolved.

10. How long does it typically take to repair OBDII code B1340 GMC for the Left Air Temperature Actuator?

The repair time can vary based on the cause of the issue and the complexity of the repair required. Replacing the left air temperature actuator or addressing wiring issues may take a few hours, while diagnosing and fixing problems with the HVAC control module can take longer.