P1686 – OBD-II DTC

OBD-II DTC P1686 – Metering Oil Pump Malfunction

DTC P1686 meaning

DTC P1686 refers to a malfunction in the metering oil pump, which is responsible for regulating the flow of oil in the engine. This code indicates that the Engine Control Module (ECM) has detected an issue with the oil pump’s operation, potentially affecting engine performance and lubrication.

DTC P1686 symptoms

Common symptoms associated with DTC P1686 may include:

• Illuminated check engine light
• Decreased engine performance
• Unusual engine noises
• Increased oil consumption
• Engine stalling or misfiring

DTC P1686 causes

Several factors can lead to the triggering of DTC P1686, including:

• Faulty metering oil pump
• Wiring issues or damaged connectors
• Low oil levels or poor oil quality
• Faulty ECM or software issues
• Oil pressure sensor malfunction

DTC P1686 seriousness

DTC P1686 is considered a serious issue as it can lead to inadequate lubrication of engine components. This can result in increased wear and tear, potential engine damage, and ultimately, engine failure if not addressed promptly.

How to diagnose DTC P1686

To diagnose DTC P1686, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P1686 code.
2. Check for any additional trouble codes that may provide more context.
3. Inspect the oil level and quality, ensuring it meets manufacturer specifications.
4. Examine the wiring and connectors related to the metering oil pump for damage or corrosion.
5. Test the metering oil pump operation using a multimeter or appropriate diagnostic tool.
6. Check the oil pressure sensor for proper functionality.
7. Evaluate the ECM for any software updates or faults.

How to fix DTC P1686 step-by-step instructions

To fix DTC P1686, follow these steps:

1. Ensure the engine is off and the vehicle is on a level surface.
2. Check and top off the engine oil if it is low.
3. Replace the oil filter and change the oil if it is dirty or degraded.
4. Inspect and repair any damaged wiring or connectors related to the metering oil pump.
5. Replace the metering oil pump if it is found to be faulty.
6. Test the oil pressure sensor and replace it if necessary.
7. Reprogram or replace the ECM if it is determined to be faulty.
8. Clear the DTC using an OBD-II scanner and take the vehicle for a test drive to ensure the issue is resolved.

How to erase DTC P1686

To erase DTC P1686, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Access the trouble codes menu on the scanner.
4. Select the option to clear or erase trouble codes.
5. Confirm the action and wait for the scanner to complete the process.
6. Disconnect the scanner and start the engine to verify that the check engine light is off.

Recommended tools for OBD-II diagnostics

Explore our expert picks: The Best OBD2 Scanners for 2025

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.