B1379

What Does Code B1379 Mean?

The diagnostic trouble code B1379 indicates an “Oil Change Reset Button Circuit Short To Ground.” This code is typically set by a body control module (BCM), instrument cluster (IC), or a specific dedicated control module responsible for managing driver information systems and maintenance reminders. The oil change reset button is an input device, usually located on the instrument cluster, a multi-function stalk, or the dashboard, allowing the operator to reset the vehicle’s oil life monitoring system after an oil change service. The control module monitors the voltage or resistance on this specific input circuit. Under normal conditions, when the button is not pressed, the circuit is designed to be in an open state, presenting a high impedance or a specific pull-up voltage. When the button is pressed, it typically momentarily closes the circuit, pulling the signal voltage low (to ground) or changing its resistance to signal the reset command. Code B1379 is triggered when the control module continuously detects a low voltage or a near-zero resistance on this circuit, characteristic of a direct short to ground, even when the button is not being actuated. This sustained short prevents the module from accurately receiving an open-circuit signal and correctly interpreting button presses, thereby compromising the functionality of the oil life reset feature.

Common Symptoms

• Inability to reset the oil life monitor: This is the primary and most direct symptom. Even after an oil change, the system will not allow the oil life percentage or indicator to be reset.
• Persistent “CHANGE OIL SOON” or “SERVICE OIL” messages: The instrument cluster or driver information display may continuously show warnings related to overdue oil maintenance, even if the oil has been recently changed.
• Malfunction Indicator Lamp (MIL) or Service Engine Soon light: While not universally tied to B-codes, some vehicle manufacturers may illuminate the MIL for certain BCM-related faults that affect driver-facing functionality.
• Oil life monitor displaying a stuck or incorrect value: The system might consistently show 0% oil life, or a very low percentage, or potentially a constantly high percentage if the short is misinterpreted as a continuous reset signal by some system designs (less common for a ‘short to ground’).

What Causes the Code B1379?

• Damaged wiring harness: The wiring connecting the oil change reset button to its respective control module (BCM/IC) may be chafed, pinched, or abraded, causing the conductor to make continuous contact with the vehicle’s chassis or another ground source.
• Faulty oil change reset button/switch: The internal contacts within the button or switch assembly itself may be physically stuck in a closed (grounded) position, or moisture/debris may be creating a conductive bridge between the contacts, leading to a permanent short to ground.
• Corrosion in electrical connectors: Water intrusion or severe corrosion within the electrical connectors for the button, the instrument cluster, or the BCM can create an unintended conductive path to ground, mimicking a short.
• Internal short within the instrument cluster or control module: Although less common, an internal fault or component failure within the instrument cluster or the BCM responsible for monitoring this input circuit could cause it to falsely detect a short to ground.

How to Diagnose and Troubleshoot

A systematic approach using appropriate diagnostic tools is crucial for resolving B1379:

1. Perform a Thorough Visual Inspection: Begin by visually inspecting the oil change reset button assembly and its surrounding area. Check for any obvious physical damage, loose connections, or signs of water intrusion. Trace the wiring harness from the button to the primary control module (BCM/IC) where possible, looking for chafed, pinched, or corroded wires and connectors.
2. Retrieve Wiring Diagrams: Obtain the vehicle-specific wiring diagram for the oil life reset circuit. This will be indispensable for identifying the signal wire, power supply, and ground points at both the button and the control module connectors. Note the specific pinouts.
3. Disconnect and Test the Button Circuit for Short to Ground:
   • Locate and disconnect the electrical connector directly at the oil change reset button/switch.
   • Using a digital multimeter (DMM) set to ohms (resistance) mode, measure the resistance between the signal pin of the harness side connector (the part leading back to the control module) and a known good chassis ground point.
   • If the DMM reads near 0 ohms or a very low resistance value (e.g., less than 50 ohms), this confirms a short to ground exists within the wiring harness between this connector and the control module. Proceed to trace and repair the wiring.
   • If the DMM reads infinite resistance (OL or open circuit), the wiring harness itself is likely not shorted, suggesting the fault lies within the button/switch or the control module.
4. Test the Oil Change Reset Button/Switch Component:
   • With the button’s connector still disconnected, use the DMM in continuity or resistance mode across the terminals of the button component itself (if it’s a standalone switch).
   • When the button is NOT pressed, the resistance should be infinite (open circuit).
   • When the button IS pressed, the resistance should drop to near 0 ohms (closed circuit/continuity).
   • If the button consistently shows near 0 ohms regardless of whether it’s pressed or not, the button assembly is faulty and internally shorted.
5. Check for Voltage at the Module (Advanced): If the wiring and button test normal, the issue might be internal to the control module. With the key in the ON position (engine OFF), carefully backprobe the signal wire at the control module’s connector. Compare the measured voltage to the expected ‘unpressed’ state voltage (typically battery voltage or a stable pull-up voltage). A persistent low voltage (near 0V) at this point, despite the button being unpressed and the wiring testing good, suggests an internal module fault.
6. Utilize a Diagnostic Scan Tool: Connect an advanced diagnostic scan tool and access the live data stream for the BCM or instrument cluster. Look for a parameter related to the “Oil Life Reset Button” status or input. If the scan tool consistently displays “Pressed,” “Active,” or “Short to Ground” when the button is not being pressed, it corroborates the diagnostic findings and points to the location of the short.

Recommended Repairs and Solutions

Once the source of the short has been accurately identified, implement the following repairs:

• Repair or Replace Damaged Wiring: If the diagnostic process identified a short within the wiring harness, the damaged section must be repaired. Use appropriate automotive-grade wire, solder connections, and seal with heat-shrink tubing to ensure a durable and waterproof repair. If the damage is extensive or involves multiple conductors, it may be more practical to replace the entire affected segment of the wiring harness. Ensure all repaired wiring is properly routed and secured to prevent future chafing or damage.
• Replace the Faulty Oil Change Reset Button/Switch: If the internal testing confirmed that the button itself is shorted, it must be replaced. This replacement can range from a standalone button to part of a larger assembly, such as a multi-function stalk, a bezel component on the dashboard, or even an integral part of the instrument cluster. Consult the vehicle’s service manual for specific removal and installation procedures.
• Clean or Replace Corroded Connectors: If corrosion was found to be the cause of the short, carefully clean the affected terminals using an electrical contact cleaner and a small bristle brush. Ensure all corrosion is completely removed and the connection is dry. If the corrosion has caused significant damage to the terminals (e.g., pitting, deformation), the connector housing and/or individual terminals should be replaced to ensure a reliable electrical connection.
• Control Module Replacement (Last Resort): Only after thoroughly verifying that the wiring harness, connectors, and the reset button itself are functioning correctly and free of shorts, and if all signs still point to an internal module fault, should replacement of the BCM or instrument cluster be considered. This is generally a less common cause for B1379. Be aware that module replacement often necessitates reprogramming or “coding” the new module to the vehicle’s specific configuration using a factory-level scan tool.
• Post-Repair Verification: After completing any repair, clear the DTC B1379 using a scan tool. Turn the key ON, then OFF, and attempt to reset the oil life monitor several times to confirm proper functionality. Re-check for DTCs to ensure the code does not return. Monitor the scan tool’s live data for the oil life reset button input to confirm it now correctly reflects the button’s pressed and unpressed states.