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I have a 1994 Jeep Cherokee with a 4.0L, 6 cylinder engine. I just took it to emissions and it failed the Nox portion. I've read that it could be the catalytic converter or EGR valve. Could you let me know what could be causing it to fail emissions?
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Welcome to 10w40.com. I have
Welcome to 10w40.com. I have listed the causes of a failed emissions test below. Oxygen (O2) Sensor -
A failed O2 sensor can cause the engine to run rich and raise carbon monoxide (CO) emissions.
Fuel Pressure Regulator -
A failed fuel pressure regulator can cause the engine to run rich and raise carbon monoxide (CO) emissions.
Manifold Absolute Pressure (MAP) Sensor -
A low vacuum signal to the MAP sensor or high signal voltage can cause the engine to run rich and raise carbon monoxide (CO) emissions.
Engine Coolant Temperature (ECT) Sensor -
A failed ECT sensor can cause the engine to run rich and raise carbon monoxide (CO) emissions.
Catalytic Converter -
The catalytic converter may fail to reduce carbon monoxide (CO) emissions. Good luck be sure to contact us @10w40.com.