What Is the P1133 Code?
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The P1133 OBD code is a manufacturer-specific code that applies to manufacturers such as GM, Chevy, Buick, Toyota, and Isuzu. It relates to your vehicle’s heated oxygen sensor (HO2S) and its functionality. The Powertrain Control Module (PCM) sets the code when it detects an insufficient number of switching cycles of the HO2S between a rich running and a lean running condition during a specified period: usually around 90 seconds. The switching sensor 1 in the code’s definition signifies the oxygen sensor located upstream or in front of the catalytic converter.
It’s important to note that heated oxygen sensors don’t switch independently. Instead, a working sensor reacts, or switches, from reporting a lean-running condition to then reporting a rich-running condition. It responds to changes that it notices in the level of oxygen found in the exhaust system. This process takes place because, for a car to maintain the optimal 14.7:1 fuel ratio, it needs the guidance of the upstream oxygen sensor. So, when you start your engine, the PCM begins a counter to measure the number of times the upstream oxygen sensor notices changes in the oxygen levels in the exhaust stream so that the PCM can then input the optimal air/fuel mixture. The oxygen sensor validates the engine combustion process, while the ECM takes in that data to maintain the correct fuel trim so that the engine doesn’t run too lean or too rich. It maintains the correct mixture when the engine starts, runs rich, or heats up more and can combust the air/fuel mixture more thoroughly. When the PCM doesn’t collect the number of switches that it’s expecting during the count, it sets the P1133 code.
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What Are the Symptoms of a P1133 Code?
The first symptom you will notice with the P1133 code is an illuminated check engine light set by the PCM. You may also notice that your vehicle cannot smoothly start and is having difficulties turning over. Rough idling also occurs during this time, and there is a good chance that your car will begin to consume more fuel during this state. If you do not address the issue for some time, then your vehicle may also experience catalytic converter damage. You may notice black smoke emitting from your exhaust tailpipe in some cases.
What Are Some Causes of a P1133 Code?
A few causes can cause the P1133 to appear in your vehicle. The first is that you may have a defective heated oxygen sensor. There could also be an open or shorted sensor harness on the bank one side of the engine, which is the side of the engine that contains the number one cylinder. If there are electrical connection issues on the bank one side of sensor one, then this will undoubtedly trigger the P1133 code. Finally, any leaks in the vacuum system will also cause the code to appear.
How Serious Is the P1133 Code?
The P1133 code could eventually become a severe code, although it doesn’t pose immediate driveability issues to your car. You may notice that your engine is running rougher because of the inability of the PCM to maintain the correct air/fuel ratio. This can eventually lead to other issues related to rich or lean running conditions and potentially leave you with higher repair bills. You generally don’t want to continue operating your car in such conditions because they aren’t ideal and can cause further stress on your vehicle’s internal components. You should take your vehicle to a certified service center sooner rather than later to keep your repair costs from skyrocketing due to further engine damage.
Can I Still Drive with a P1133 Code?
As we mentioned, you will physically be able to drive your car once the P1133 code sets, but qualified technicians do not recommend doing so for extended periods. This is because you are forcing your engine to run on inadequate air and fuel ratios that can cause further strain on your engine and its internal components. You want to isolate the issue once it arises and have a qualified technician repair any needed parts before you cause further damage to your engine.
How Easy Is It to Diagnose a P1133 Code?
The diagnostic process of the P1133 code begins with using a scanning tool to track and measure the short and long-term fuel trim values in your engine. A technician will then assess the oxygen sensor and its wiring harness because they could damage from debris or engine heat. Also, engine vibrations can cause damage to the sensor and the harness, so it’s essential to assess the actual condition of these components. The technician will also check the wiring condition leading to the heated oxygen sensor and look for any burning or corrosion. They will also check the wiring connectors to make sure that everything is plugged in as it should be and that there isn’t any visible damage. Furthermore, a technician should check for exhaust and vacuum systems leaks.
How Difficult Is It to Inspect a P1133 Code?
The inspection process of the P1133 code requires attention to detail so that you don’t end up misdiagnosing and repairing the wrong component. This is a process that requires several advanced tools and is best left in the hands of qualified technicians with the experience needed to work on these issues. With that said, undertaking this as a DIY project at home is not recommended because you could potentially cause more damage to your engine. Instead, a technician will take the time to repair any leaks in the vacuum or exhaust system that could be causing the P1133 issue. They will then repair or replace the HO2S bank one sensor harness if that is causing the problem. More than likely, though, the issue lies with the oxygen sensor itself, so this will need replacing if it’s defective. The technician will also repair any poor electrical connections leading to and from the oxygen sensor.
Need Additional Help with Your P1133 Code?
By following the guidelines we’ve set forth here, you should be able to address the P1133 code issue before it spreads and becomes a more significant issue to deal with. You’ll be able to take the proper steps to have your vehicle inspected by the right technician to get your car back into optimal running condition and back on the road.
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