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Check Engine, VDC, and Cruise Control Lights Flashing on 2020 Forester

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Diana O. · rep 0 · May 22, 3:13 AM · 1 replies · solved · Question

Vehicle: 2020 Subaru Forester Premium

Hello Subaru community,

I'm experiencing a common but frustrating issue with my 2020 Subaru Forester Premium. The Check Engine Light, VDC (Vehicle Dynamics Control) light, and the Cruise Control indicator are all flashing simultaneously. This happened suddenly while driving on the highway.

I pulled over, turned the car off and on, and the lights remained. I checked the gas cap, tightened it, but no change. The car seems to be driving normally, no noticeable loss of power or strange noises. I don't have my own scanner handy right now.

Is this a common 'limp mode' type of warning for a specific issue? What should I be looking for? Any quick fixes or common culprits for this combination of lights on a newer Forester?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:13 AM

0

ClearTheCode admin answer:

The combination of a flashing Check Engine Light (CEL), VDC light, and Cruise Control light is a very common diagnostic indicator in modern Subarus, including your 2020 Forester. This isn't necessarily a 'limp mode' in the traditional sense, but rather the vehicle's system disabling related functions (like VDC and Cruise Control) as a safety precaution when the CEL is triggered.

Common Causes for this Combination of Lights:

  1. Loose or Faulty Gas Cap: This is surprisingly common. Even if you've tightened it, sometimes the seal can be compromised, or the cap itself might be faulty. A small EVAP leak can trigger the CEL.
  2. Minor Engine Misfire: A slight misfire that might not be immediately noticeable while driving can trigger the CEL. The ECU detects an anomaly in combustion, and as a precaution, disables systems that rely on precise engine operation.
  3. Oxygen Sensor Issues: A failing O2 sensor can cause incorrect air-fuel ratio readings, leading to a CEL.
  4. EVAP System Leaks: Beyond the gas cap, other components of the Evaporative Emission Control System (EVAP) can develop leaks, triggering the CEL.
  5. Catalytic Converter Issues: Similar to the P0420 code, an inefficient catalytic converter can also cause this light combination.
  6. Mass Air Flow (MAF) Sensor: A dirty or failing MAF sensor can send incorrect air intake readings, affecting fuel mixture and triggering the CEL.

Troubleshooting Steps:

  1. Get the Codes Read: The absolute first step is to get the diagnostic trouble codes (DTCs) read. Most auto parts stores offer this service for free. The specific code(s) will narrow down the problem significantly.
  2. Check Gas Cap Again: Ensure it's tightened until it clicks several times. Sometimes it takes a few drive cycles for the system to reset after a gas cap issue.
  3. Visual Inspection: Briefly check for any obvious loose hoses, especially around the air intake or vacuum lines.

When to See a Shop:

  • Immediately after getting the codes read, if you're unsure how to interpret them or if they point to a complex issue.
  • If the car starts exhibiting noticeable driveability issues (rough idle, loss of power, stalling).
  • If the codes indicate a serious engine or transmission problem (e.g., P030X for persistent misfires, P0700 for transmission control issues).
  • If the lights persist after checking the gas cap and you don't have access to a scanner or the tools to diagnose further.

While this light combination often points to a relatively minor issue, it's always best to get the codes read promptly to prevent potential damage or ensure safe operation.

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