Last updated: November 9, 2026 – By Eddie Brennan

November 2026 update: reconfirmed exhaust leak, O2 sensor, muffler, and catalytic converter cost ranges.

Exhaust and emissions guide 2026: the system runs manifold, O2 sensors, catalytic converter, resonator, muffler, tailpipe. Installed repair costs: exhaust leak or gasket $100 to $400, oxygen sensor $200 to $500 each, muffler $150 to $500, resonator or mid-pipe $150 to $600, catalytic converter $900 to $2,500 and up to $5,000-plus on luxury. Warning signs include a check engine light, loud roar, rotten-egg smell, exhaust smell in the cabin, weak acceleration, and worse fuel economy.

The exhaust system carries burned gases out of the engine and cleans them up on the way, and its costs range from a $100 leak repair to a $2,500-plus catalytic converter. Front to back it runs from the manifold through the oxygen sensors and catalytic converter, then the resonator, muffler, and tailpipe. Most exhaust problems announce themselves – a check engine light, a growing roar, a rotten-egg smell, or a drop in power and fuel economy. Catching them early matters, because a cheap exhaust leak left alone can foul the oxygen sensors or overwork the catalytic converter, turning a $150 fix into a four-figure one. These are estimated ranges that vary by vehicle, so confirm your specific car locally.

Emissions work was a big part of my day in Columbus – half the check-engine lights that rolled in traced back to this system. What I want you to take away is the pecking order of cost: leaks and sensors are cheap, the catalytic converter is the one that hurts, and the cheap problems are often what damage the expensive part. So this guide covers what each piece does, the warning signs, and what the common repairs cost, with links to detailed pages.

What the exhaust system does

Two jobs, really. First, it routes hot exhaust gas away from the engine and quiets it down – the manifold collects it, pipes carry it back, and the resonator and muffler tune and muffle the noise so your car isn’t deafening. Second, and just as important, it cleans up emissions. The oxygen sensors measure how much oxygen is in the exhaust so the computer can fine-tune the fuel mixture, and the catalytic converter chemically converts harmful gases into less harmful ones before they leave the tailpipe.

That emissions role is why exhaust problems so often trigger a check engine light rather than just noise. A bad oxygen sensor throws off the fuel mixture, hurting economy and power; a failing catalytic converter sets emission codes and can clog, choking the engine. The parts also depend on each other – an unfixed leak lets in extra air that confuses the sensors and can overheat the converter. Understanding that chain is what keeps a small exhaust problem from cascading into a big one.

Repair costs, cheapest to most expensive

Here’s the rough installed cost for the common exhaust and emissions repairs, cheapest first. Treat these as estimated ranges, since parts and access vary a lot by vehicle.

Repair Typical installed cost Detailed estimate
Exhaust leak / gasket $100–$400 Exhaust leak repair cost
Oxygen (O2) sensor $200–$500 each O2 sensor signs
Muffler $150–$500 Varies by material and fit
Resonator / mid-pipe $150–$600 Depends on the section
Catalytic converter $900–$2,500+ Catalytic converter signs

The catalytic converter is the outlier, and on some luxury and performance vehicles it can climb past $5,000 because the part itself is expensive – it contains precious metals, which is also why converter theft has been a problem. A muffler or a leak is a modest bill; the converter is the one to protect. That protection is mostly about fixing the cheap stuff early, which brings us to the warning signs.

Straight From the Invoice: the cheap fix that saved the expensive one

These are jobs I either did myself or watched come through the bay – a small leak, a sensor, and a converter that a leak helped kill.

Invoice #1 – 2015 Honda Civic, exhaust leak caught early, Columbus OH

Small manifold gasket leak fixed for a couple hundred dollars before it could foul the downstream sensor or converter. Landed at the low end of the leak range. Lesson: an exhaust leak is cheap now and dangerous to ignore, because it feeds the expensive failures downstream.

Invoice #2 – 2013 Ford F-150, single O2 sensor, Ohio

Check engine light for a lazy oxygen sensor; one sensor replaced in the $200-to-$300 range, and fuel economy came back. Lesson: an O2 sensor code is usually a few-hundred-dollar fix, not a catalytic converter – get the code read before assuming the worst.

Invoice #3 – 2012 Subaru Outback, converter killed by neglect, Ohio

A long-ignored misfire and rich running fouled the catalytic converter until it clogged; the replacement ran well over a thousand. The underlying engine issue was cheap; the converter it destroyed wasn’t. Lesson: converters usually don’t fail on their own – an unfixed engine or leak problem takes them out, so address the root cause fast.

Warning signs and what they point to

The exhaust system is good about warning you. A check engine light is the most common signal, since the oxygen sensors and catalytic converter are monitored by the computer. A loud roar or rumble that grows over time usually means a leak or a rusted-through muffler or pipe. A rotten-egg, sulfur smell points at the catalytic converter, and any exhaust smell inside the cabin is a safety issue to address promptly, because exhaust contains carbon monoxide.

Performance symptoms matter too. Weak acceleration and worse fuel economy can come from a clogged catalytic converter choking the engine or a bad oxygen sensor throwing off the fuel mixture. Black, blue, or white smoke from the tailpipe each point at different problems – fuel, oil, or coolant – that are worth diagnosing. If you notice signs of an exhaust leak or a check engine light, get the code read early, while the fix is still cheap. Our check engine light guide covers reading those codes.

Shop Talk

When you get a “catalytic converter” code (like P0420), don’t let anyone sell you a converter on that code alone. Nine times out of ten the converter didn’t fail by itself – it was killed by a misfire, an oil-burning problem, or an exhaust leak, and if you replace the converter without fixing that, the new one fouls too. A good shop diagnoses why the converter went bad first. Also, before you spend big on a converter, ask whether an aftermarket, CARB-compliant unit fits your car and state rules – it can cost far less than the dealer part, though some states and some vehicles require an exact match, so confirm before buying.

What Gets Misdiagnosed

The costliest exhaust misdiagnosis is replacing a catalytic converter that was fouled by something else. A converter code tells you the converter isn’t working, not why – and the “why” is usually a misfire, an oil or coolant leak into the cylinders, or an exhaust leak upstream. Swap the converter without fixing the cause and the new one clogs the same way, so you’ve spent four figures and bought yourself a repeat. A proper diagnosis finds the root cause first, which often turns a converter scare into a much cheaper repair.

The other frequent mix-up is treating every check engine light in this family as a converter. An oxygen-sensor code, an EVAP leak, or a small exhaust leak can produce similar symptoms and lights but cost a fraction of a converter. Reading the specific code separates a $250 sensor from a $1,500 converter. So don’t accept a converter quote off a dashboard light alone – get the code, get the cause, and you’ll usually find the real fix is smaller than feared. That’s the whole game with emissions repairs.

The Real Number

Exhaust repairs run cheap to expensive: an exhaust leak is $100 to $400, an oxygen sensor $200 to $500 each, a muffler $150 to $500, and a catalytic converter $900 to $2,500 and up – all estimated ranges by vehicle. The converter is the one that hurts, and it usually doesn’t fail on its own, so a converter code means find the root cause (a misfire, a leak, oil burning) before spending. Fix leaks and sensor codes early while they’re cheap, because neglect is what sends the bill to the converter. And never buy a converter off a dashboard light alone – get the specific code read first.

Frequently Asked Questions

How much does exhaust repair cost?

It depends heavily on the part. An exhaust leak or gasket repair runs $100 to $400, an oxygen sensor $200 to $500 each, a muffler $150 to $500, and a resonator or mid-pipe $150 to $600. The big one is the catalytic converter at $900 to $2,500 and up, reaching $5,000-plus on some luxury vehicles because the part contains precious metals. These are estimated ranges that vary by vehicle. Because the converter is so much pricier than the rest, getting the specific diagnostic code read is worth it – it separates a few-hundred-dollar sensor or leak from a four-figure converter before you commit to any repair.

What are the signs of an exhaust problem?

The most common is a check engine light, since the oxygen sensors and catalytic converter are monitored by the computer. You may also hear a loud roar or rumble that grows over time, which usually means a leak or a rusted muffler or pipe. A rotten-egg sulfur smell points at the catalytic converter, and any exhaust smell inside the cabin should be addressed promptly because exhaust contains carbon monoxide. Weak acceleration, worse fuel economy, and colored smoke from the tailpipe are other signs. Catching these early matters, because a cheap leak left alone can damage the expensive catalytic converter downstream.

Why is my catalytic converter bad?

A catalytic converter rarely fails on its own – it’s usually killed by another problem feeding it. A misfire dumps unburned fuel into the converter and overheats it; an engine burning oil or coolant coats and clogs it; and an unfixed exhaust leak or rich fuel mixture degrades it over time. That’s why replacing a converter without fixing the underlying cause just fouls the new one. When you get a converter code, the right move is to diagnose why it went bad first. Often the root cause is a much cheaper repair, and fixing it protects whatever converter you install. See our catalytic converter signs guide.

Can I drive with an exhaust leak?

A small exhaust leak may not strand you, but it’s not something to ignore, for two reasons. First, safety: a leak ahead of the cabin can let exhaust fumes, including carbon monoxide, reach the interior, which is dangerous, so any exhaust smell inside the car means fix it now. Second, cost: a leak lets in extra air that confuses the oxygen sensors and can overheat the catalytic converter, so a cheap leak left alone can lead to expensive downstream damage. A leak is one of the cheaper exhaust repairs at $100 to $400, and fixing it early protects the pricier parts. Don’t let it linger.

How do I know if it’s the oxygen sensor or the catalytic converter?

The reliable way is to read the diagnostic code, because the symptoms overlap but the cost doesn’t. An oxygen-sensor code points at a $200-to-$500 sensor, while a converter-efficiency code like P0420 points at the converter – though even that code can be triggered by a bad sensor or a leak rather than the converter itself. A scan tool and a proper diagnosis sort it out, sometimes with live sensor data. This is exactly why you shouldn’t accept a converter quote off a dashboard light alone: the difference between the two repairs is often more than a thousand dollars, and reading the code is cheap or free at many parts stores.

Is a muffler delete or straight pipe worth it?

A muffler delete makes the car much louder and is popular for that reason, but weigh the downsides. It can violate local noise and emissions laws, may fail inspection, can trigger drone on the highway, and on many modern cars it doesn’t add meaningful power. Removing emissions equipment like the catalytic converter is a separate and more serious matter – it’s illegal for street use in the US and will fail emissions testing. If you just want a better sound, an aftermarket performance muffler is the legal route. Consider your state’s rules and inspection requirements before modifying the exhaust, since undoing it later costs money too.

Why does my exhaust smell like rotten eggs?

A rotten-egg or sulfur smell almost always points at the catalytic converter. The fuel contains small amounts of sulfur, and a properly working converter processes it; when the converter is failing or overwhelmed – often because the engine is running rich or misfiring – that sulfur comes through as the distinctive smell. So the odor is a sign to have the converter and the engine’s fuel mixture checked. Because the converter is expensive, it’s worth diagnosing the cause: sometimes it’s a fuel-mixture or sensor problem making a healthy converter smell, which is far cheaper to fix than the converter itself. Don’t ignore it, as it signals the emissions system isn’t working right.

Sources

Exhaust and emissions repair cost ranges verified against 2026 industry cost reporting on November 9, 2026. Figures are estimated ranges that vary widely by vehicle; confirm with a shop for your specific car.

Related Guides

Eddie Brennan

Eddie Brennan spent 11 years as an ASE Master Certified technician at an independent shop in Columbus, OH, where half the check-engine lights traced back to the exhaust and emissions system – his A6 electrical/electronic certification covers the sensor diagnostics behind those codes. He takes no referral fees and drives a 250,000-mile 2015 Subaru Outback and a 2020 Ford F-150.