B3748 Code - Air Flow Control 3 Feedback Circuit Range/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 Mode Actuator, Mode Actuator harness is open or shorted, Mode 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
- B3748 indicates Air Flow Control 3 Feedback Circuit Range/Performance.
- Common causes
- Common causes include Faulty Mode Actuator, Mode Actuator harness is open or shorted, Mode 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 B3748 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 B3748?
- Faulty Mode Actuator
- Mode Actuator harness is open or shorted
- Mode Actuator circuit poor electrical connection
- Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module
How to Fix the DTC B3748?
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 B3748 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 B3748 code?
Need more information on how to fix the B3748 code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the B3748 code diagnosed by a professional: Find a repair shop in your area
Information for Specific Makes
- B3748 Buick — Air Flow Control 3 Feedback Circuit Range/Performance
- B3748 Cadillac — Air Flow Control 3 Feedback Circuit Range/Performance
- B3748 Chevrolet — Air Flow Control 3 Feedback Circuit Range/Performance
- B3748 GMC — Air Flow Control 3 Feedback Circuit Range/Performance
Frequently Asked Questions about B3748 Code
1. What are the common symptoms of OBDII code B3748 related to the Air Flow Control 3 Feedback Circuit Range/Performance?
- Common symptoms include poor engine performance, rough idling, stalling, and potential decrease in fuel efficiency.
2. What are the possible causes of OBDII code B3748?
- The code B3748 can be triggered by issues such as a faulty air flow sensor, damaged wiring or connectors, vacuum leaks, or a malfunctioning PCM (Powertrain Control Module).
3. How can I diagnose the cause of OBDII code B3748 myself?
- You can start by checking the air flow sensor for any signs of damage or contamination. Inspect the wiring and connectors for any visible issues and perform a vacuum leak test. If necessary, use an OBDII scanner to further diagnose the problem.
4. Is it safe to continue driving with OBDII code B3748 present?
- It is not recommended to drive with the B3748 code active, as it can lead to engine performance issues and potential damage if left unresolved.
5. How can I repair OBDII code B3748 related to Air Flow Control 3 Feedback Circuit Range/Performance?
- Repair steps may include replacing the air flow sensor, repairing or replacing damaged wiring/connectors, fixing any vacuum leaks, or reprogramming/resetting the PCM.
6. Can a dirty air filter cause OBDII code B3748 to trigger?
- While a dirty air filter can affect engine performance, OBDII code B3748 is more commonly related to issues with the air flow sensor, wiring, or vacuum leaks.
7. How much does it typically cost to repair OBDII code B3748?
- The cost of repairing OBDII code B3748 can vary depending on the specific cause of the issue, but it may range from $100 to $500 or more, including parts and labor.
8. Will disconnecting the battery reset OBDII code B3748?
- Disconnecting the battery may temporarily clear the code, but it is recommended to diagnose and repair the underlying issue to prevent the code from reoccurring.
9. Can a DIY enthusiast with basic automotive knowledge fix OBDII code B3748?
- Depending on the cause of the code, a DIY enthusiast with basic automotive knowledge may be able to address simpler issues like checking and cleaning connectors or replacing the air flow sensor.
10. Is it necessary to visit a mechanic for OBDII code B3748, or can I ignore it?
- It is advisable to address OBDII code B3748 promptly to prevent potential engine damage and ensure optimal vehicle performance. Consulting a mechanic for diagnosis and repair is recommended.
Discuss the causes and fixes for B3748 OBDII Code
Code B3748 comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
