B138A Code - Control Module Voltage Reference Output Circuit
Quick Answer
The B138A diagnostic trouble code (DTC) refers to a fault in the control module voltage reference output circuit. Common causes include Wiring harness damage or corrosion, Poor electrical connections or loose connectors, Faulty control module. 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
- B138A indicates Control Module Voltage Reference Output Circuit.
- Common causes
- Common causes include Wiring harness damage or corrosion, Poor electrical connections or loose connectors, Faulty control module.
- 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 B138A Description
The B138A diagnostic trouble code (DTC) refers to a fault in the control module voltage reference output circuit. This code typically indicates that there is an issue with the power supply or voltage regulation for a specific control module in the vehicle. Control modules are essential components in modern vehicles as they control various systems such as engine management, transmission, ABS, airbags, and more. The voltage reference output circuit ensures that the control module receives a consistent and accurate voltage supply for proper operation.
Common Causes of B138A
- Wiring harness damage or corrosion.
- Poor electrical connections or loose connectors.
- Faulty control module.
- Issues with the vehicle's voltage regulator.
- Damage to the control module's internal components.
Symptoms of B138A
- Dashboard warning lights, such as the Check Engine Light or ABS Light, may illuminate.
- Erratic behavior from affected systems, such as engine misfires or transmission shifting issues.
- Decreased fuel efficiency or performance.
- Inconsistent or rough idling.
- Loss of power steering assist or other power-dependent functions.
How to Fix B138A
- Begin by conducting a thorough visual inspection of the wiring harness and connectors for any signs of damage or corrosion. Repair or replace any compromised components.
- Test the voltage output from the control module to determine if it is within the specified range. If not, investigate potential issues with the voltage regulator.
- Use a multimeter to check the continuity of the circuit and ensure that all connections are secure.
- If the control module is found to be faulty, it may need to be replaced with a new unit. Ensure that the replacement module is programmed and configured correctly for the vehicle.
- Clear the DTC and conduct a test drive to verify that the issue has been resolved and that all affected systems are functioning properly.
Cost to Fix B138A
The cost of repairing the control module voltage reference output circuit can vary depending on the specific cause of the issue and the extent of the repairs needed. In general, parts for this repair could range from $100 to $500, while labor costs could add another $100 to $300. Overall, the total cost of addressing this issue could be in the range of $200 to $800. However, it's important to note that these are rough estimates, and actual costs may vary based on factors such as location, vehicle make and model, and the shop's labor rates. Be sure to consult with a qualified mechanic or repair shop for a more accurate cost assessment.
Tech Notes for B138A
DTC B138A 07: Control Module Voltage Reference Output Circuit High Voltage
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Code B138A Information for Specific Makes
- B138A Buick — Control Module Voltage Reference Output Circuit
- B138A Cadillac — Control Module Voltage Reference Output Circuit
- B138A Chevrolet — Control Module Voltage Reference Output Circuit
- B138A GMC — Control Module Voltage Reference Output Circuit
Frequently Asked Questions about B138A Code
What does the OBDII code B138A mean?
The OBDII code B138A indicates a problem with the Control Module Voltage Reference Output Circuit, which can affect the operation of various vehicle systems that depend on this voltage reference.
What are common symptoms of the B138A code?
Common symptoms may include warning lights on the dashboard, malfunctioning electronic components, or issues with vehicle systems such as the infotainment or climate control systems.
What can cause the B138A code to trigger?
Causes can include a faulty control module, a short circuit in the voltage reference wire, poor connections, or issues with the power supply to the control module.
How can I diagnose the B138A code?
To diagnose the B138A code, check the vehicle’s wiring and connectors for damage, test the voltage reference output with a multimeter, and inspect related components for faults.
What are some common repair solutions for the B138A code?
Common repairs may include repairing or replacing damaged wiring, replacing the faulty control module, or addressing any connection issues in the voltage reference circuit.
Will the B138A code clear itself after repairs?
The code may clear itself after the underlying issue is resolved and the vehicle is driven for a certain distance, but it can also be cleared manually with an OBDII scanner.
Can I drive my vehicle with the B138A code?
Driving with the B138A code is not recommended, as it can lead to further electrical issues and may affect the performance and safety of the vehicle.
Is the B138A code serious?
Yes, while it may not prevent the vehicle from running, it indicates an underlying issue with the electrical system that could lead to more severe problems if not addressed.
How much does it typically cost to fix the B138A code?
Repair costs can vary widely depending on the specific cause of the code, but they can range from a simple wiring fix to several hundred dollars for a control module replacement.
Can I fix the B138A code myself?
If you have experience with automotive electrical systems, you may be able to diagnose and repair the issue yourself. However, if you're unsure, it's best to consult a professional mechanic.
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