The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2018 V60 Cross Country T5 Check Engine Light, reduced MPG, exhaust smell

0

Laura J. · rep 0 · May 22, 5:12 AM · 1 replies · solved · Question

Vehicle: 2018 Volvo V60 Cross Country T5

Hey everyone,

I'm looking for some advice on my 2018 Volvo V60 Cross Country T5. The Check Engine Light (CEL) came on a few days ago, and it's stayed on. Along with that, I've noticed a definite drop in my fuel economy, and occasionally, I can smell exhaust fumes, especially when the car is idling or I'm stopped at a light. It's not a strong smell, but it's definitely there.

The car seems to be driving okay otherwise, no major loss of power, but the combination of the CEL, worse MPG, and the exhaust smell has me worried. I'm thinking it might be something with the catalytic converter or an O2 sensor.

Has anyone with a V60 Cross Country or similar T5 engine experienced these symptoms? What was the cause, and what should I prepare for?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:12 AM

0

ClearTheCode admin answer:

Your 2018 Volvo V60 Cross Country T5 exhibiting a Check Engine Light (CEL), reduced fuel economy, and an exhaust smell strongly suggests an issue within the exhaust system or engine's emissions control. Your suspicion about the catalytic converter or O2 sensors is a good starting point.

Common Causes:

  1. Oxygen (O2) Sensor Failure:
    • Upstream (Pre-Cat) O2 Sensor: A faulty sensor here can send incorrect air-fuel ratio data to the ECU, leading to inefficient combustion, reduced MPG, and potentially a rich mixture that causes an exhaust smell.
    • Downstream (Post-Cat) O2 Sensor: This sensor monitors the catalytic converter's efficiency. If it detects that the converter isn't cleaning exhaust gases effectively, it will trigger a CEL.
  2. Catalytic Converter Failure: Over time, catalytic converters can become clogged or fail internally. This reduces their ability to convert harmful pollutants, leading to increased emissions, a distinct sulfur or rotten egg smell (though sometimes just a general exhaust smell), and reduced engine efficiency.
  3. Exhaust Leaks: A leak in the exhaust manifold, pipes, or muffler can allow fumes to escape, sometimes into the cabin, and can also affect O2 sensor readings.
  4. Misfires or Engine Performance Issues: While you haven't noted a major power loss, persistent misfires or other engine problems can send unburnt fuel to the catalytic converter, damaging it over time and causing the symptoms you describe.

When to See a Shop:

The CEL indicates that the Engine Control Unit (ECU) has detected a fault. The first step is to retrieve the diagnostic trouble codes (DTCs). Common codes for these symptoms include:

  • P0420: Catalyst System Efficiency Below Threshold (Bank 1) - This is a very common code indicating a failing catalytic converter.
  • P0133: O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) - Indicates a slow-responding upstream O2 sensor.
  • P0139: O2 Sensor Circuit Slow Response (Bank 1 Sensor 2) - Indicates a slow-responding downstream O2 sensor.
  • P0171/P0172: System Too Lean/Rich - Can be related to O2 sensor issues or other engine problems affecting the air-fuel mixture.

A professional technician will:

  1. Read DTCs: Confirm the specific codes stored in the ECU.
  2. Inspect Exhaust System: Visually check for leaks, damage, or signs of catalytic converter failure.
  3. Test O2 Sensors: Use a scan tool to monitor O2 sensor readings in real-time to assess their functionality.
  4. Perform Backpressure Test: If a clogged catalytic converter is suspected, a backpressure test can confirm it.

Addressing these issues promptly is important not only for fuel economy and air quality but also to prevent further damage to the engine or other emissions components.

Menu

Help & account