This vehicle was traveling at 60 mph, and the engine suddenly stopped producing power. The driver coasted to the side of the road, switched the engine off, restarted the vehicle, and continued driving. However, the minimal power problem soon happened again. We quickly diagnosed and repaired the problem.
Diagnosis
Our Jeep technician test-drove the vehicle and confirmed the problem of the engine computer going into "limp" mode with minimal engine power when it reached operating temperature. Back at our shop, the technician scanned the vehicle for engine computer error codes and found one related to catalytic converter efficiency. This error code can indicate a plugged catalytic converter.
This Jeep has two different catalytic converters: a primary converter and a secondary converter with two oxygen O2 sensors, an upstream O2 sensor before the primary converter, and a downstream O2 sensor after the second catalytic converter. Unfortunately, there is no oxygen O2 sensor between the two catalytic converters. A middle oxygen O2 sensor would inform the technician which catalytic converter was defective. Without an oxygen sensor in the middle the technician must manually inspect each catalytic converter to discover which one is defective.
The technician used a remote scope camera to view inside the exhaust system and visually confirmed the primary catalytic converter was clogged. The technician recommended replacing the primary #1 catalytic converter.
Cause
Do Jeeps have catalytic converter problems?
Unfortunately, a failed primary Catalytic Converter is a common problem with the Jeep Patriot 4-cylinder engines. Most failures happen on vehicles mainly used for short-distance driving in city stop-and-go traffic conditions. The catalytic converter does not become hot enough to clean itself and becomes plugged.
Can an oxygen sensor cause a Catalytic Converter failure?
No, but the oxygen sensor can trigger a check engine warning light and error code regarding the catalytic converter. The oxygen sensor is just responding to a catalytic converter that is not working correctly.
The oxygen sensors measure the level of emissions in the exhaust gases going into and exiting the catalytic converter. When the oxygen sensors detect that the catalytic converter is not "cleaning" the exhaust gases enough to meet vehicle emissions specifications, a catalytic converter efficiency error code is set.
What will cause a false catalytic converter warning light?
Two engine problems can cause a false catalytic converter warning error code. Before replacing a catalytic converter, a technician should check for engine cylinder misfires. A rough-running engine is a strong indicator of an engine misfire.
Second, the technician needs to check for exhaust system leaks. A rapid, repeating "tick-tick-tick" or "puff-puff-puff" sound that changes with engine speed is usually a good indication of an exhaust leak. Exhaust leaks will be more pronounced when the engine is cold. Two common exhaust leaks are a cracked exhaust manifold or a leaking exhaust manifold gasket.
If the engine runs smoothly, and there are no exhaust leaks, the catalytic converter usually has failed. To confirm a plugged catalytic converter, the technician can remove the exhaust pipes downstream of the catalytic converter and do an interior visual inspection of the catalytic converter. The technician can also use an optical camera scope to inspect the internal condition of the catalytic converter.
Can driving conditions cause a Catalytic Converter failure?
Yes. Extended engine idling and repeated short trips in cold weather can damage catalytic converters. For catalytic converters to reach their optimum operating temperature, they need approximately 20 minutes of highway driving to clean and regenerate the catalyst. Vehicles that get intermittent use commonly have plugged catalytic converter problems.
Repair
2012 Jeep Patriot catalytic converter replacement. The primary catalytic converter on this Jeep model is a maniverter assembly, which includes the catalytic converter, exhaust manifold, and exhaust outlet pipe. The technician disconnected the lower secondary catalytic converter from the maniverter. Next, the technician unbolted the lower sub-frame from the engine and lowered the entire engine assembly to allow for the unbolting and removal of the maniverter. They then installed the new maniverter, a new manifold gasket, and a new upstream O2 oxygen sensor before putting the engine back into position and reattaching the sub-frame. Next, the technician cleared the computer error codes with a diagnostic scanner, test-drove the vehicle, and confirmed the repair was successful.
Repair Cost
The following repair price is a US national average and will vary depending on your location.
A national 2012 Jeep Patriot Catalytic Converter replacement cost example is $2,450. This price breaks down into 36% labor and 64% parts for a new, quality primary catalytic converter, exhaust pipe flange gasket, exhaust bolt and spring, oxygen sensor, and exhaust manifold gasket set. Note: this price does not include the diagnostic fee, shop supplies fee, environmental disposal fee, and taxes.
Catalytic Converter Price
Be careful comparing part prices for the 2012 Jeep Patriot 4-cylinder 4x4. First, this vehicle uses two different catalytic converters, a primary converter and a secondary converter, both of which have very different prices. Also, many low-cost, budget catalytic converters are of poor quality, will not meet Jeep emissions standards, often do not work out of the box, or will quickly fail. A reputable auto repair shop will use quality parts and provide a full guarantee.
Tips
How can you prevent a Jeep catalytic converter from failing?
If your Jeep has a check engine light on, have it inspected and repaired as soon as possible. A rough-running engine, engine misfiring, engine burning oil, or exhaust leaks can damage the catalytic converter. Quickly fixing these problems will extend the life of your Jeep catalytic converter.
If the vehicle is used mostly for short trips or stop-and-go city driving, it is recommended to drive the vehicle on the highway for at least 20 minutes every 100 miles.
What Causes Catalytic Converters to Fail?
Bad Spark Plugs or Bad Spark Plug Wires. Spark plugs that don't fire or misfire force unburnt fuel into the exhaust system. This excess fuel ignites inside the hot catalytic converter, causing it to overheat and eventually fail.
Another cause for Jeep Catalytic Converter failure is fuel injector malfunction. The problem can be a fuel injector failure, an injector wiring problem, an engine temperature sensor failure, or an engine management computer failure. Fuel injectors can leak, resulting in excess fuel delivery and catalytic converter overheating and failure. Plugged fuel injectors can cause engine misfires and fuel mixture control problems that lead to catalytic converter damage.
Unburnt fuel or engine oil entering the catalytic converter causes uncontrolled interior heat. This excessive heat inside the catalytic converter melts the internal catalyst honeycomb support, often causing a rattle from the converter and eventually restricting the exhaust flow, choking the engine.
Another common catalytic converter contaminant is engine coolant, which enters the catalytic converter through the exhaust from a leaking intake manifold gasket or a leaking head gasket. The burnt coolant residue builds up inside the catalytic converter, plugging the internal catalyst honeycomb and eventually blocking exhaust flow through the catalytic converter.
The restricted exhaust flow results in a loss of engine power, decreased fuel mileage, engine overheating, and triggering a check engine light.
Recommended Jeep Repair Shop Near Ann Arbor, MI
Contact State Street Auto Service for all Jeep service and repair in the Ann Arbor, Michigan area. Our Jeep technicians have the skill and experience to diagnose and repair your Jeep Patriot problems correctly. We are Jeep service specialists.