Introduction:
The B1336 diagnostic trouble code (DTC) indicates a problem with the door ajar circuit for the right rear (RR) door in a vehicle. This means the vehicle's computer (usually the Body Control Module or BCM) is detecting an open circuit in the wiring or components responsible for signaling whether the right rear door is properly closed. This can lead to the "door ajar" warning light remaining illuminated, even when the door is securely latched, and potentially affect other vehicle systems.
Table: B1336 Door Ajar RR Circuit Open - Causes, Symptoms, and Solutions
| Component/Symptom/Cause | Description | Potential Solution |
|---|---|---|
| Right Rear (RR) Door Ajar Switch | This is the primary component that signals the door's open/closed status to the BCM. It's a simple switch that closes or opens a circuit depending on the door latch position. | Test: Use a multimeter to check continuity when the door is open and closed. Solution: Replace the faulty switch. |
| Wiring Harness/Connectors - Right Rear Door | The wiring harness and connectors carry the signal from the door ajar switch to the BCM. Damage, corrosion, or loose connections can interrupt the circuit. | Inspect: Visually inspect the wiring harness for damage, cuts, or abrasion. Check connectors for corrosion or loose pins. Test: Use a multimeter to check for continuity and voltage along the circuit. * Solution: Repair or replace damaged wiring or connectors. Use dielectric grease on connectors after cleaning. |
| Body Control Module (BCM) | The BCM receives the signal from the door ajar switch and controls the "door ajar" warning light and potentially other related functions. A faulty BCM can misinterpret or fail to receive the signal. | Test: This requires specialized diagnostic equipment and knowledge. Consult a qualified technician. Solution: In rare cases, the BCM may need reprogramming or replacement. |
| Door Latch Assembly | The door latch assembly physically secures the door and often incorporates the door ajar switch. A malfunctioning latch can prevent the switch from operating correctly. | Inspect: Ensure the latch mechanism moves freely and engages properly. Test: The door ajar switch functionality is usually integrated into the latch. Test the switch as described above. * Solution: Replace the door latch assembly if it's damaged or malfunctioning. |
| "Door Ajar" Warning Light Stays On | This is the most common symptom. The light remains illuminated even when the right rear door is closed and latched securely. | Diagnosis: This is the symptom that leads to investigating the B1336 code. Follow the troubleshooting steps for the other components. Solution: Address the underlying cause of the open circuit. |
| Dome Lights Stay On | The door ajar circuit often controls the dome lights. If the circuit is open, the dome lights may remain illuminated even when the door is closed. | Diagnosis: This symptom further points to a problem with the door ajar circuit. Solution: Address the underlying cause of the open circuit. |
| Vehicle Security System Issues | In some vehicles, the door ajar signal can affect the vehicle's security system. It might prevent the system from arming or trigger false alarms. | Diagnosis: This symptom is less common but possible, especially in vehicles with integrated security systems. Solution: Address the underlying cause of the open circuit. |
| Corrosion | Corrosion can build up on electrical contacts, especially in areas exposed to moisture and the elements. This can create resistance and interrupt the circuit. | Inspect: Carefully inspect all connectors and terminals for signs of corrosion. Solution: Clean corroded contacts with a wire brush or contact cleaner. Apply dielectric grease to prevent future corrosion. |
| Broken Wire Inside Insulation | Wires can break internally without any visible external damage to the insulation. This can be difficult to diagnose. | Test: Use a multimeter to check for continuity while wiggling the wiring harness. This can help identify intermittent breaks. Solution: Repair or replace the damaged section of the wiring harness. |
| Grounding Issues | Although the code refers to an "open" circuit, a poor ground can sometimes mimic an open circuit condition. | Inspect: Check the grounding points for the door ajar circuit and ensure they are clean and secure. Solution: Clean and tighten grounding points. Add additional grounding if necessary. |
| Aftermarket Accessories | Improperly installed aftermarket accessories (e.g., alarms, remote starters) can sometimes interfere with the door ajar circuit. | Inspect: Check for any recently installed aftermarket accessories and ensure they are properly wired and not interfering with the door ajar circuit. Solution: Disconnect or properly wire the aftermarket accessory. |
| Water Intrusion | Water leaks into the vehicle can damage wiring and electrical components, leading to corrosion and circuit problems. | Inspect: Check for signs of water intrusion in the door area, such as dampness, mold, or water stains. Solution: Repair the water leak and dry out the affected area. Replace any damaged wiring or components. |
Detailed Explanations:
Right Rear (RR) Door Ajar Switch: This small, often plunger-style switch is the primary sensor. When the door is closed and the latch engages, it presses the switch, signaling to the BCM that the door is secure. When the door is open, the switch is released, indicating an open door. A faulty switch will not accurately report the door's status.
Wiring Harness/Connectors - Right Rear Door: The wiring harness is a bundle of wires that connect the door ajar switch to the BCM. The connectors are the points where the wiring harness plugs into the switch and the BCM. Damage to the wiring (cuts, abrasions, breaks) or corrosion/loose connections in the connectors can interrupt the electrical signal, creating an open circuit.
Body Control Module (BCM): The BCM is the central computer responsible for controlling various body-related functions in the vehicle, including the door ajar warning system. It receives input from the door ajar switch and activates the warning light and other related functions. While less common, a faulty BCM can misinterpret the signal or fail to process it correctly. Diagnosing a BCM issue often requires specialized diagnostic tools and expertise.
Door Latch Assembly: The door latch assembly not only secures the door but also often houses the door ajar switch. If the latch mechanism is damaged or misaligned, it may not properly engage the switch, leading to an inaccurate reading. Sometimes the switch is integrated into the latch, making replacement of the entire assembly necessary.
"Door Ajar" Warning Light Stays On: This is the most obvious and frustrating symptom. The warning light remains illuminated on the dashboard even when the right rear door is securely closed. This indicates that the system believes the door is still open, triggering the warning.
Dome Lights Stay On: The door ajar circuit often controls the dome lights. If the circuit is open, the BCM thinks the door is open and keeps the dome lights illuminated, potentially draining the battery if left unattended for extended periods.
Vehicle Security System Issues: In some vehicles, the door ajar signal is integrated with the vehicle's security system. An incorrect door ajar signal can prevent the system from properly arming or even trigger false alarms, leading to inconvenience and potential security vulnerabilities.
Corrosion: Corrosion is a common enemy of electrical connections. It forms on metal surfaces, especially in areas exposed to moisture and the elements, creating resistance and hindering the flow of electricity. Corroded connectors and terminals can prevent the door ajar switch signal from reaching the BCM.
Broken Wire Inside Insulation: This is a particularly challenging problem to diagnose because the wire may appear intact from the outside. However, the internal copper conductor may be broken due to stress, vibration, or repeated bending. This can create an intermittent open circuit that is difficult to pinpoint. Wiggling the wiring harness during testing can sometimes reveal the break.
Grounding Issues: While the B1336 code indicates an "open" circuit, a poor or missing ground connection can sometimes mimic this condition. A weak or corroded ground can prevent the door ajar switch signal from properly returning to the BCM, resulting in an inaccurate reading.
Aftermarket Accessories: Improperly installed aftermarket accessories, such as alarms, remote starters, or aftermarket lighting, can sometimes interfere with the door ajar circuit. These accessories may tap into the vehicle's wiring harness and disrupt the signal, leading to false readings.
Water Intrusion: Water leaks into the vehicle, particularly in the door area, can cause significant damage to wiring and electrical components. Water can accelerate corrosion, short circuits, and other electrical problems, including issues with the door ajar circuit.
Frequently Asked Questions:
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What does the B1336 code mean? It means there's an open circuit in the door ajar system for the right rear door, indicating the system isn't receiving the correct signal.
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Can I fix the B1336 code myself? Depending on your mechanical skills, you may be able to fix it by inspecting and repairing wiring, connectors, or replacing the door ajar switch. However, diagnosing BCM issues requires specialized equipment.
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How much does it cost to fix a B1336 code? The cost varies depending on the cause. Replacing a switch might be inexpensive, while addressing wiring harness damage or BCM issues could be more costly.
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Will driving with a B1336 code damage my car? Driving with a B1336 code is generally safe, but it can drain your battery if the dome lights stay on and can affect your security system.
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Where is the door ajar switch located? It's usually integrated into the door latch assembly on the right rear door.
Conclusion:
The B1336 code indicates a fault in the right rear door ajar circuit, typically caused by a faulty switch, damaged wiring, or corroded connectors. Thorough troubleshooting is key to identifying and resolving the underlying issue, ensuring proper operation of the door ajar warning system and related vehicle functions.