Introduction
The B1371 diagnostic trouble code (DTC) indicates a fault within the illuminated entry relay circuit in a vehicle's electrical system. This circuit is responsible for activating interior lights when the doors are unlocked or opened, providing illumination for entering the vehicle, especially in low-light conditions. A failure in this circuit can result in the interior lights not functioning as intended, leading to inconvenience and potential safety concerns. Understanding the causes, symptoms, and troubleshooting steps for a B1371 code is crucial for proper diagnosis and repair.
Table: B1371 Illuminated Entry Relay Circuit Failure Details
| Category | Description | Potential Impact |
|---|---|---|
| Definition | Illuminated Entry Relay Circuit Failure | Interior lights fail to illuminate when doors unlock or open. |
| Common Symptoms | Interior lights not working upon door opening/unlocking; Delayed or intermittent interior light function; No interior lights at all; Battery drain (in some cases); Security system malfunctions (rare). | Inconvenience; Safety hazard in low-light conditions; Potential battery issues; Security system issues. |
| Possible Causes | Faulty illuminated entry relay; Wiring issues (shorts, opens, corrosion); Defective door switch(es); Faulty Body Control Module (BCM); Blown fuse; Grounding issues. | Electrical system malfunction; Interior lighting problems; Potential for further electrical damage. |
| Diagnostic Steps | Scan for DTCs; Visually inspect wiring and connectors; Test the illuminated entry relay; Check door switch operation; Test the Body Control Module (BCM) output; Check fuses; Check grounds; Use a multimeter to check for voltage and continuity. | Accurate identification of the root cause of the problem. |
| Potential Solutions | Replace the faulty illuminated entry relay; Repair or replace damaged wiring; Replace defective door switch(es); Reprogram or replace the Body Control Module (BCM); Replace blown fuse; Repair grounding issues. | Restoration of proper illuminated entry function. |
| Related Codes | B1370, B1372, B1373, B1374 (related to illuminated entry or other BCM functions) | Provides context and helps to narrow down the problem. |
| Tools Required | OBD-II scanner; Multimeter; Wiring diagram; Test light; Basic hand tools (screwdrivers, pliers, etc.) | Proper diagnosis and repair of the electrical circuit. |
| Difficulty Level | Moderate (requires electrical troubleshooting skills) | Determines whether professional assistance is needed. |
| Typical Repair Cost | Varies greatly depending on the cause; Relay replacement ($20-$100); Wiring repair ($50-$200); BCM replacement ($200-$1000+) | Budgeting for the repair. |
| Preventative Measures | Regular vehicle maintenance; Visual inspection of wiring and connectors; Prompt repair of any electrical issues. | Minimizing the risk of future illuminated entry circuit failures. |
Detailed Explanations
Definition: The B1371 code specifically points to a malfunction within the electrical circuit controlling the illuminated entry relay. This relay is responsible for powering the interior lights when the vehicle doors are opened or unlocked via the key fob. The Powertrain Control Module (PCM) or Body Control Module (BCM) detects an issue with the relay's operation or the circuit itself, triggering the code.
Common Symptoms: The most noticeable symptom is the failure of the interior lights to illuminate when a door is opened or the vehicle is unlocked remotely. Other symptoms include delayed or intermittent operation of the interior lights, or no interior lights at all. In some cases, a battery drain might occur if the relay is stuck in the 'on' position. While less common, a B1371 code can sometimes be associated with security system malfunctions.
Possible Causes: A faulty illuminated entry relay itself is a primary suspect. However, wiring problems, such as shorts, open circuits, or corrosion within the wiring harness, can also cause the issue. Defective door switch(es), which signal the BCM when a door is opened, can also prevent the lights from activating. In rarer cases, a faulty Body Control Module (BCM), which controls many of the vehicle's electronic functions, may be the culprit. A blown fuse protecting the circuit or a grounding issue can also lead to the B1371 code.
Diagnostic Steps: Start by using an OBD-II scanner to confirm the presence of the B1371 code. Next, perform a visual inspection of the wiring and connectors associated with the illuminated entry system, looking for any signs of damage or corrosion. Test the illuminated entry relay using a multimeter to check for proper operation. Check the door switch operation to ensure they are sending the correct signals to the BCM. If necessary, test the Body Control Module (BCM) output to verify that it is sending the correct signal to the relay. Check all relevant fuses and grounds to ensure they are in good working order. Use a multimeter to check for voltage and continuity throughout the circuit, following a wiring diagram for the vehicle.
Potential Solutions: The most common solution is to replace the faulty illuminated entry relay. If wiring damage is found, repair or replace the damaged wiring sections. If a door switch is defective, replace the defective door switch(es). If the BCM is faulty, it may need to be reprogrammed or replaced. A blown fuse should be replaced with one of the correct amperage. Repair grounding issues by cleaning and tightening ground connections.
Related Codes: Codes like B1370, B1372, B1373, and B1374 might be related to the illuminated entry system or other BCM functions. Investigating these codes in conjunction with B1371 can provide a more complete picture of the electrical system's health.
Tools Required: An OBD-II scanner is essential for reading diagnostic trouble codes. A multimeter is needed for testing voltage, continuity, and resistance. A wiring diagram for the vehicle's electrical system is crucial for tracing circuits. A test light can be used to check for power at various points in the circuit. Basic hand tools like screwdrivers, pliers, and wire strippers are also necessary.
Difficulty Level: Diagnosing and repairing a B1371 code is generally considered to be of moderate difficulty. It requires a basic understanding of automotive electrical systems and the ability to use a multimeter and wiring diagram. If you are not comfortable working with electrical circuits, it is best to seek professional assistance.
Typical Repair Cost: The repair cost can vary significantly depending on the cause of the problem. A simple relay replacement might cost between $20 and $100. Wiring repair could range from $50 to $200, depending on the extent of the damage. A BCM replacement can be the most expensive option, potentially costing $200 to $1000 or more.
Preventative Measures: Regular vehicle maintenance, including visual inspection of wiring and connectors, can help prevent future illuminated entry circuit failures. Addressing any electrical issues promptly can also help prevent them from escalating into more significant problems.
Frequently Asked Questions
What does the B1371 code mean? The B1371 code signifies a fault in the illuminated entry relay circuit, indicating a problem with the system that controls the interior lights when the doors are opened or unlocked.
How do I fix a B1371 code? Troubleshooting involves checking the relay, wiring, door switches, fuses, and the BCM; repair or replace the faulty component.
Can a bad relay cause a battery drain? Yes, if the illuminated entry relay is stuck in the 'on' position, it can continuously power the interior lights, leading to a battery drain.
Is it safe to drive with a B1371 code? While generally safe, the lack of interior lights can be a safety concern in low-light conditions, and a persistent electrical issue can potentially lead to further problems.
How do I test an illuminated entry relay? Use a multimeter to check for proper voltage and continuity across the relay's terminals, following the vehicle's wiring diagram.
Conclusion
The B1371 DTC indicates a problem with the illuminated entry relay circuit, which can cause interior lighting issues. Thorough diagnosis and repair, following the steps outlined above, are crucial for restoring proper functionality and preventing potential safety hazards.