When diagnosing engine issues, the OBD-II code P0685 is a significant indicator that requires immediate attention. This code pertains to the power relay circuit that supplies voltage to the Engine Control Module (ECM) or Powertrain Control Module (PCM).
What Does the P0685 Code Mean?
OBD-II Code P0685 is defined as an ECM/PCM Power Relay Control Circuit/Open. This code indicates that the engine computer (PCM) has detected a problem with the power relay that supplies battery voltage to itself.
What Causes the P0685 Code?
Several factors can trigger the P0685 code, including:
- Failure of the Powertrain Control Module (PCM)
- Failure of the PCM power relay
- Wiring issues or poor connections
What Are the Symptoms of the P0685 Code?
The most common symptoms associated with the P0685 code include:
- Engine may not start
- Hard or no start, especially in cold weather
How Serious Is the P0685 Code?
The P0685 code is classified as urgent. It indicates a significant malfunction that can lead to severe damage to the vehicle or pose a risk to the driver and passengers. Immediate action is necessary to avoid further complications.
How to Diagnose the P0685 Code
To diagnose the P0685 code, follow these steps:
- Utilize an OBD-II scanner to confirm the presence of the P0685 code.
- Inspect the power relay and associated wiring for signs of damage or corrosion.
- Test the PCM for proper operation and ensure it is receiving the correct voltage.
- Check for any additional trouble codes that may indicate related issues.
Common Repairs for the P0685 Code
If you encounter the P0685 code, the following repairs may be needed:
- Replacing the Powertrain Control Module (PCM)
- Replacing the PCM power relay
- Repairing or replacing damaged wiring and connectors
How Much Does It Cost to Fix the P0685 Code?
The cost to fix the P0685 code can vary significantly based on the underlying issue. Repairs may range from $100 to $1000, depending on whether you need to replace the PCM or the power relay.
Can I Fix the P0685 Code Myself?
While some DIY enthusiasts may be able to troubleshoot wiring issues or replace a relay, dealing with the PCM typically requires professional expertise. It’s essential to understand the risks involved and consider consulting a professional mechanic for a thorough diagnosis and repair.
