The B1552 diagnostic trouble code (DTC) indicates a problem within the deck lid (trunk) release circuit of a vehicle. This code signifies an "open" circuit, meaning there's a break or interruption in the electrical pathway that allows the trunk to open electronically. Diagnosing and resolving this issue is crucial for restoring full functionality and convenience to the vehicle.
The presence of a B1552 code suggests a fault that prevents the signal from the control module (often the Body Control Module or BCM) from reaching the deck lid release actuator. This can lead to frustration and inconvenience, especially when carrying groceries or luggage. Understanding the potential causes and troubleshooting steps is essential for addressing this problem effectively.
| Component/Symptom | Description | Possible Cause |
|---|---|---|
| B1552 Code | Deck lid release circuit open. | Interruption in the electrical circuit preventing trunk release. |
| Deck Lid Release Actuator | Solenoid or motor that physically opens the trunk latch. | Faulty actuator, open circuit, corrosion at connector. |
| Wiring Harness/Connectors | Electrical wires and connectors connecting the BCM to the deck lid release actuator. | Damaged wires (cut, frayed, corroded), loose or corroded connectors. |
| Body Control Module (BCM) | Computer module that controls various electrical functions, including trunk release. | BCM malfunction (less common, but possible), internal failure. |
| Fuse | Protective device in the circuit. | Blown fuse due to short circuit or overload. |
| Switch/Button | Trunk release button (inside the car or on the key fob). | Faulty switch, internal damage, corrosion. |
| Key Fob | Remote control for locking/unlocking and trunk release. | Low battery, fob malfunction, programming issue. |
| Symptom: Trunk Won't Open Electronically | The primary symptom of the B1552 code. | Any of the above causes can prevent the trunk from opening electronically. |
| Symptom: Intermittent Trunk Opening | Trunk opens sometimes, but not always. | Loose connection, intermittent wiring fault, failing actuator. |
| Multimeter Readings | Used to test voltage, continuity, and resistance in the circuit. | Inconsistent or absent readings indicate a fault. |
| Scan Tool Data | Provides diagnostic information and trouble codes. | Shows the B1552 code and potentially other related codes. |
| Ground Connection | The return path for the electrical current. | Corroded or loose ground connection affecting the circuit. |
| Circuit Diagram | Visual representation of the electrical circuit. | Essential for tracing the circuit and identifying components. |
| Actuator Resistance | Electrical resistance of the actuator coil. | Out-of-range resistance indicates a faulty actuator. |
| Battery Voltage | Voltage supplied to the circuit. | Low voltage can affect the actuator's performance. |
| CAN Bus Communication | Communication network between vehicle modules. | Fault in CAN bus can affect BCM communication. |
| Manual Override | Mechanical way to open the trunk (usually a key or lever inside the trunk). | If manual override works, the issue is likely electrical. |
| Short to Ground | Electrical circuit fault where a wire touches the vehicle chassis. | Can cause a blown fuse and trigger the B1552 code. |
| Short to Voltage | Electrical circuit fault where a wire touches a positive voltage source. | Can damage components in the circuit. |
| Corrosion | Buildup of oxidation on electrical connections. | Reduces conductivity and can cause intermittent failures. |
| Rodent Damage | Wires chewed by rodents. | Can cause open circuits and short circuits. |
| Aftermarket Accessories | Added accessories that interfere with the electrical system. | Improperly installed accessories can cause electrical problems. |
| Water Intrusion | Water entering the electrical system. | Can cause corrosion and short circuits. |
Detailed Explanations
B1552 Code: This is the core indicator of the problem. The B1552 code specifically means the vehicle's computer has detected an open circuit in the electrical path responsible for activating the trunk release. This open circuit prevents the electrical signal from reaching the actuator, thus preventing the trunk from opening electronically. The code is typically stored in the BCM.
Deck Lid Release Actuator: The deck lid release actuator is the electromechanical component responsible for physically releasing the trunk latch. It's usually a solenoid or a small electric motor. When the BCM sends a signal, the actuator energizes, pulling a lever or cable that unlatches the trunk. A faulty actuator won't respond to the signal, even if the circuit is otherwise functional.
Wiring Harness/Connectors: The wiring harness and connectors form the electrical pathways connecting the BCM to the trunk release actuator, as well as the switch and ground. Damage to the wiring, such as cuts, frays, or corrosion, can break the circuit. Similarly, loose or corroded connectors can interrupt the flow of electricity.
Body Control Module (BCM): The BCM is a central computer module that manages various electrical functions within the vehicle, including the deck lid release. The BCM receives the signal from the trunk release button and sends a signal to the actuator. While less common, a BCM malfunction can prevent it from sending the correct signal.
Fuse: Fuses are protective devices designed to break an electrical circuit if there's an overload or short circuit. A blown fuse in the deck lid release circuit will interrupt the power supply, preventing the actuator from working. Always replace a blown fuse with one of the same amperage rating.
Switch/Button: The trunk release switch, located inside the car or on the key fob, initiates the trunk opening process. A faulty switch can fail to send the signal to the BCM, preventing the trunk from opening. Internal damage or corrosion can render the switch inoperable.
Key Fob: The key fob uses a radio frequency to communicate with the vehicle's security system and can activate the trunk release. A low battery in the fob, a fob malfunction, or a programming issue can prevent the trunk from opening remotely.
Symptom: Trunk Won't Open Electronically: This is the most obvious symptom. The trunk will not open using the interior button, key fob, or exterior button (if equipped). This symptom directly correlates with the B1552 code, indicating a problem in the electrical circuit.
Symptom: Intermittent Trunk Opening: Sometimes the trunk opens, and other times it doesn't. This suggests a loose connection, an intermittent wiring fault, or a failing actuator. These intermittent issues can be challenging to diagnose.
Multimeter Readings: A multimeter is an essential tool for diagnosing electrical problems. It can be used to test voltage, continuity (whether a circuit is complete), and resistance in the circuit. Inconsistent or absent readings indicate a fault, such as a broken wire or a faulty component.
Scan Tool Data: A scan tool can retrieve diagnostic trouble codes (DTCs) stored in the vehicle's computer, including the B1552 code. It can also provide live data from various sensors and modules, which can help pinpoint the source of the problem.
Ground Connection: A good ground connection is essential for completing the electrical circuit. A corroded or loose ground connection can increase resistance, preventing the actuator from receiving sufficient power.
Circuit Diagram: A circuit diagram (wiring diagram) is a visual representation of the electrical circuit. It shows the location of all components, the wiring connections, and the flow of electricity. A circuit diagram is invaluable for tracing the circuit and identifying potential problem areas.
Actuator Resistance: The electrical resistance of the actuator coil can be measured with a multimeter. An out-of-range resistance reading (either too high or too low) indicates a faulty actuator.
Battery Voltage: The battery voltage needs to be within a certain range for the electrical system to function properly. Low battery voltage can affect the actuator's performance and trigger the B1552 code.
CAN Bus Communication: The Controller Area Network (CAN) bus is a communication network that allows various modules in the vehicle to communicate with each other. A fault in the CAN bus can affect communication between the BCM and other modules, potentially triggering the B1552 code.
Manual Override: Most vehicles have a manual override for opening the trunk, usually a key or a lever inside the trunk. If the manual override works, it suggests the problem is likely in the electrical system rather than the latch mechanism itself.
Short to Ground: A short to ground occurs when a wire in the circuit accidentally touches the vehicle's chassis (ground). This creates a low-resistance path to ground, causing a large current flow and potentially blowing a fuse.
Short to Voltage: A short to voltage occurs when a wire in the circuit accidentally touches a positive voltage source. This can damage components in the circuit and cause unpredictable behavior.
Corrosion: Corrosion is the buildup of oxidation on electrical connections, often caused by moisture. Corrosion increases resistance, reducing conductivity and potentially causing intermittent failures.
Rodent Damage: Rodents can chew on wires, causing open circuits and short circuits. Inspect the wiring harness for any signs of rodent damage.
Aftermarket Accessories: Improperly installed aftermarket accessories can interfere with the electrical system and cause various problems, including the B1552 code.
Water Intrusion: Water entering the electrical system can cause corrosion and short circuits. Check for signs of water intrusion in the trunk area and around electrical connectors.
Frequently Asked Questions
What does the B1552 code mean? The B1552 code indicates an open circuit in the deck lid (trunk) release circuit, preventing the trunk from opening electronically. This means there is a break in the electrical path.
How do I fix a B1552 code? Troubleshooting involves checking fuses, wiring, connectors, the deck lid release actuator, and the BCM. Use a multimeter to test for continuity and voltage.
Can a bad fuse cause the B1552 code? Yes, a blown fuse in the deck lid release circuit can interrupt the power supply and trigger the B1552 code. Always replace with the correct amperage.
Is the B1552 code serious? While not a critical safety issue, it prevents the trunk from opening electronically, causing inconvenience. Addressing the problem is recommended to restore functionality.
Can a faulty key fob cause the B1552 code? Potentially, a key fob with a dead battery or a malfunctioning trunk release button can mimic the symptoms of a B1552 code. Try a spare key fob to rule this out.
Conclusion
The B1552 code indicates an open circuit in the deck lid release system, often leading to the inability to open the trunk electronically. Thorough diagnostics, including checking fuses, wiring, connectors, and the actuator, are crucial for identifying and resolving the root cause of the problem. Addressing the B1552 code will restore the convenience of electronic trunk release.