B3749 GMC Code - Air Flow Control 7 Feedback Circuit Performance
Quick Answer
The Heating, Ventilation, and Air Conditioning (HVAC) Control Module controls the HVAC actuators to regulate the airflow and temperature through the HVAC system. Common causes include Faulty Recirculation Actuator, Recirculation Actuator harness is open or shorted, Recirculation 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
- B3749 GMC indicates Air Flow Control 7 Feedback Circuit Performance.
- Common causes
- Common causes include Faulty Recirculation Actuator, Recirculation Actuator harness is open or shorted, Recirculation 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.
Code B3749 GMC Description
The HVAC control module determines the door position by counting motor pulses on one of the control circuits. The HVAC control module converts the pulses to counts with a range of 0-255 counts.
When a calibration or recalibration procedure is performed, the HVAC control module calculates the door travel range. The HVAC control module compares the total number of pulses to calibrated limits. If the total pulse count is less than or equal to the maximum calibrated limited and more that or equal to the minimum calibrated limit, then the calibration is considered successful.
What are the Possible Causes of the DTC B3749 GMC?
- Faulty Recirculation Actuator
- Recirculation Actuator harness is open or shorted
- Recirculation Actuator circuit poor electrical connection
- Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module
How to Fix the DTC B3749 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 B3749 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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Frequently Asked Questions about B3749 GMC Code
1. What are common symptoms of OBDII code B3749 GMC (Air Flow Control 7 Feedback Circuit Performance)?
- Common symptoms include rough idling, reduced engine power, poor acceleration, and possible stalling.
2. What are the typical causes of OBDII code B3749 GMC?
- The code B3749 GMC is often triggered by issues with the air flow control 7 feedback circuit, such as wiring problems, sensor malfunctions, or a faulty control module.
3. How can I diagnose the cause of OBDII code B3749 GMC?
- Proper diagnostics with a scan tool capable of reading OBDII codes is necessary to pinpoint the exact cause. Checking the wiring, connectors, sensors, and control module is recommended.
4. Can a dirty air filter trigger OBDII code B3749 GMC?
- While a dirty air filter can affect engine performance, it is unlikely to directly trigger the specific code B3749 GMC related to the air flow control 7 feedback circuit.
5. How can I repair OBDII code B3749 GMC?
- Repairing this code may involve fixing wiring issues, replacing damaged sensors, or addressing problems with the control module. It is recommended to follow the manufacturer's diagnostic and repair procedures.
6. Is it safe to continue driving with OBDII code B3749 GMC present?
- It is not recommended to continue driving with this code active, as it can lead to further engine performance issues and potential damage if left unresolved.
7. Can a DIY enthusiast fix OBDII code B3749 GMC at home?
- Depending on the underlying cause, some DIY enthusiasts with experience in automotive repair may be able to address the issues related to this code. However, proper diagnostic tools and knowledge are essential.
8. How much does it typically cost to repair OBDII code B3749 GMC at a mechanic?
- The cost of repairing this code can vary depending on the cause of the issue, the labor rates of the mechanic, and the cost of any necessary parts. It is advisable to obtain estimates from several mechanics.
9. Will resetting the OBDII code B3749 GMC turn off the check engine light?
- Resetting the code may temporarily turn off the check engine light, but if the underlying issue is not fixed, the code is likely to reappear, triggering the light again.
10. Are there any preventive measures to avoid OBDII code B3749 GMC in the future?
- Regular maintenance of the vehicle, including checking and replacing air filters, inspecting wiring for damage, and addressing any engine performance issues promptly, can help prevent the recurrence of this code.
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