07 Honda Fit Code PO420. Car missing at idle when AC is on and has trouble accelerating, especially up hills, more so with AC on
07 Honda Fit with a OBD II code PO420. Car misses at idle when AC is running. Car hesitates on acceleration especially when the AC is on. Car lacks power going uphills especially with AC on and even more so on very hot days.
My car has 310000 miles.
My car has a manual transmission.
Experienced mechanics share their insights in answering this question :
Hi there.The catalytic converter has two oxygen sensors. One oxygen sensor is positioned in front (upstream) of the catalytic converter and the other oxygen sensor is positioned at the rear (downstream). If the upstream oxygen sensor is working properly, its readings should fluctuate from when the car is at operating temperature and when running in a closed loop. When the oxygen sensors have readings that are similar to each other, it is an indication that the catalytic converter is not working as intended. If the voltage of the downstream oxygen sensor decreases, and begins to fluctuate like the upstream oxygen sensor, it means that the oxygen levels are too high and the Powertrain Control Module (PCM) will store the P0420 trouble code. This could be caused by a cracked exhaust manifold, damaged sensors or catalytic converter or electrical harness that controls the the sensors. It would be a good idea to have a professional mechanic complete an engine is misfiring inspection.
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Diagnosis: The most common cause of Honda P0420 is a bad catalytic converter, but it can be caused by anything from a faulty oxygen sensor to a rich or lean running condition, or misfires. There are many variables that could cause this code.
The P0420 code signals a low catalyst system efficiency. This code suggests that the oxygen levels are below the desired threshold (Bank 1), which most often results from problems with your car`s exhaust or fuel systems.
The most common reason for code P0420 is catalytic converter failure. There are other potential causes for this code though. It`s important to look for other codes that could explain why the converter failed. Misfires or an incorrect air-fuel ratio could be the causes of a failed converter.
Can a bad O2 sensor cause a P0420 code? Yes. A typical catalyst monitor uses the signal from the downstream oxygen sensor to determine catalyst efficiency, and the signal from the upstream sensor is a reference point. As such, failure of either the upstream or downstream oxygen sensor can cause code P0420 to set.
Can you drive with the p0420 code? In the short term, driving with a P0420 code is usually fine. The driver is not at risk because of it. This code can harm your engine and exhaust system if you drive for an extended period of time.
Code P0420 indicates that the catalytic converter is not functioning efficiently, therefore increasing the output of harmful pollutants by the vehicle.
Yes. Bad spark plugs can cause a P0420 code because when one or more spark plugs are faulty, they are not able to ignite the air and fuel mixture in the combustion chamber so the unburnt mixture, along with the Nitrogen Oxide and Carbon Monoxide from the combustion chamber will go into the catalytic converter.
A P0420 code indicates that your vehicle`s computer (PCM) has detected a problem with the catalytic converter. The catalytic converter`s function is to break down dangerous pollutants produced during the combustion cycle, lowering emissions released through the exhaust pipe.
A P0420 code is set when the upstream sensor and the downstream oxygen sensor sense the catalytic converter is not doing its job. Basically, the amount of oxygen going into the converter is not being burned, and it detects it through the downstream sensor.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
07 Honda Fit Code PO420. Car missing at idle when AC is on and has trouble accelerating, especially up hills, more so with AC on
ANSWER : Hi there.The catalytic converter has two oxygen sensors. One oxygen sensor is positioned in front (upstream) of the catalytic converter and the other oxygen sensor is positioned at the rear (downstream). If the upstream oxygen sensor is working properly, its readings should fluctuate from when the car is at operating temperature and when running in a closed loop. When the oxygen sensors have readings that are similar to each other, it is an indication that the catalytic converter is not working as intended. If the voltage of the downstream oxygen sensor decreases, and begins to fluctuate like the upstream oxygen sensor, it means that the oxygen levels are too high and the Powertrain Control Module (PCM) will store the P0420 trouble code. This could be caused by a cracked exhaust manifold, damaged sensors or catalytic converter or electrical harness that controls the the sensors. It would be a good idea to have a professional mechanic complete an engine is misfiring inspection.
when I turn my ac on my cars idle drop and stalls out and the ac is hot
ANSWER : Hello, thank you for writing in. Although the pulley is still spinning, the compressor has likely failed. If it is not properly regulating pressure in the system, one of the first signs is a warm air conditioner. Considering yours is not cooling off, the pressures are not correct. If you believe the compressor is working correctly, you may want to check for a clogged line before replacing it. Keep in mind, a blocked line has likely put extra strain on the compressor, and may cause premature failure. For more help with testing or replacing the compressor, contact our service department to schedule an appointment.
When I turn on my AC the radiator fans do not turn on. The fans do come on when the car warms up so I know they are working and the fuses are good. The AC compressor does come on and the air blows ice cold when the car is moving. Car is a 2006 Chrysler Sebring Sedan 2.7l v6.
ANSWER : The control circuit for the fans needs to be checked. For example, there is usually a condenser fan relay in the A/C electrical controls. There could be a fault with that relay and/or wiring problems, perhaps even just a loose connection, blown or loose fuse, and so forth. To resolve something like this, the recommended service is an electrical component diagnostic. If you request that diagnostic service, the responding certified mechanic will get the problem pinpointed and resolved. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
I have a engine miss codes po174 po420 are on now I had code multiple cylinder miss fire. I changed spark plug wires and plugs l
ANSWER : Hi there. Your issue might be caused by a faulty O2 sensor. You might want to read this article about the P0174 OBD-II trouble code as it will show you possible causes, symptoms and solutions to resolve the problems.
car shakes when idle and accelerating
ANSWER : It is very possible that you have a valve cover gasket or spark plug tube seal leak on your vehicle. These type of leaks will allow oil to leak onto the spark plugs causing misfires. When the engine misfires due to oil getting on the spark plug, the engine oil will burn. Since oil and tires are both petroleum products, they will both smell similar when they are burning. I would recommend having an oil leak inspection performed by a qualified professional to determine if there is an oil leak. Consider YourMechanic as an Oil/Fluid leak inspection can be peformed at your home or office.
Can i retrieve CEL code from car … forgot what code it hade in my car .. put headgasket sealer and i erase the code ..
ANSWER : Once a trouble code is erased, it cannot be retrieved. The engine controller does not have a "recycle bin" like they have on Windows. If the car still has a problem, the code will come back up after some driving. However, the controller will not turn on the CEL until it has seen the malfunction on two separate "trips." A "trip" is a driving cycle where the car is started cold, driven until it is fully warm and through a certain number of accelerations, and shut down. So you might not see the CEL for a couple of days. As for the "head gasket sealer," I wouldn’t hold out too much hope of that solving a problem. At the very best it might put off the symptoms for a short while. If you need help interpreting codes that come up, or solving a head gasket issue, contact Your Mechanic. They can send a technician to your home or office to read the codes on your car and help you decide what to do.
Car vibrates in idle and trouble accelerating after stopped
ANSWER : Hi there, thanks for writing in about your 2003 Subaru Baja. There are dozens of potential causes for the symptoms you are having. It could be an engine performance problem, such as a bad sensor. It could also be a bad motor mount or internal transmission problem. If the Check Engine Light is on, (I’m guessing it is), the first step is to retrieve the stored diagnostic trouble codes. These codes serve as a starting point for an further diagnostics. I suggest having a professional, such as one from YourMechanic, diagnose the vibrating issue firsthand to verify what repairs are needed.
High idling, jumping while idling, idle air control valve code
ANSWER : Hi there. This can be caused by the issues that you mentioned or a number of other things. You need to make sure all of the connectors are making good contact. I would then need to know what codes are in the computer to know if this is a circuit issue or not. Most of the time, it is not the circuit but instead a vacuum leak.
If there is a vacuum leak, then the vehicle will act like this and the computer cannot control the idle. Most of the time it is a bad hose or an EGR valve that is stuck open. That is the most common cause for this. I typically remove the EGR to check it to feel the diaphragm on the bottom of it to see if it is moving correctly. If you need to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair your car’s idling issue.
