What Is the P0845 Code?
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The P0845 code definition is “Transmission Fluid Pressure Sensor/Switch B Circuit.” If you see this code, it means that your vehicle’s powertrain control module (PCM) or engine control module (ECM) has identified an issue of some kind inside your transmission fluid pressure sensor switch (TFPS switch or TFPS sensor). This code often comes along with another code that specifies more of the issue with the electrical signal, such as whether the voltage is high, low, or intermittent. This generic powertrain code can show up in any OBD-II-equipped vehicle.
More About the P0845 Code
Transmission fluid pressure is a critical component of automatic transmission. In an automatic transmission, transmission fluid helps your vehicle shift in and out of gear and manage the lockup within the torque converter. The transmission fluid pressure sensor is what allows for correct transmission operating pressure; your PCM, ECM, or transmission control module (TCM) provides commands to the transmission fluid pressure sensor, which turns them into actions. When you see this code, it means there’s an issue with the circuit for switch “B,” although the specific issue can vary. It doesn’t mean there’s necessarily something wrong with the sensor itself or the transmission fluid, but instead, the circuit is operating outside of normal operating voltage.
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What Are the Symptoms of a P0845 Code?
In general, you can expect that the first symptom of diagnostic trouble code (DTC) P0845 is your check engine light turning on. The other symptoms of this engine code can vary significantly depending on the underlying cause and the severity of the problem but often have to do with mechanical issues related to transmission shifting. You may see general rough shifting or transmission slipping. If the problem continues to increase in severity, you can see high temperatures within the transmission and a decrease in fuel economy.
What Are Some Causes of a P0845 Code?
There are many causes possibly related to the P0845 diagnostic trouble code. While your most common issue is a failed TFPS sensor, there are a wide variety of possible causes of the P0845 code. This isn’t a complete list, but it can be a start:
- Intermittent open, short-to-ground, or short-to-voltage signal circuit
- Other wiring issues, including electrical connection corrosion problems
- Dirty transmission fluid, contaminated transmission fluid, or low transmission fluid level
- Internal leaks of transmission fluid
- General faulty sensors and faulty solenoid
- Blockage within the hydraulic lines
- Internal mechanical transmission issue or other internal transmission malfunction
- Faulty PCM or ECM, although this is uncommon
It’s especially important to realize that this is a fairly wide umbrella code and doesn’t even include whether the code is sending a high voltage, low voltage, or intermittent voltage. You’ll need to do further investigation to determine the core issue.
How Serious Is the P0845 Code?
DTC P0845 can be fairly serious. Any codes that have to do with your transmission will generally be important to manage earlier rather than later, as neglecting a transmission code can easily cause the code to turn into a serious problem. Transmission fixes tend to be quite expensive and difficult, but if you fix this problem early on, you’re more likely to only pay for a few hours of labor and the cost of a replacement part. If you handle the power-related fault code early, you’ll be less likely to create a serious issue for yourself down the line.
Can I Still Drive with a P0845 Code?
In many cases, code P0845 causes the vehicle to enter Limp Mode, also called Limp Home Mode or Limp-In Mode, which can cause the vehicle to start in second or third gear, then limit its speed to a specific low upper limit and shut off specific “unnecessary” systems like your air conditioning systems. This can make it frustrating to drive and impossible to drive long distances. Even if your vehicle isn’t in the Limp Mode, however, you should still avoid driving with this code active. When you have a transmission issue, continuing to drive with it can result in a faulty transmission. Get help from a professional mechanic to avoid internal transmission failure.
How Easy Is It to Diagnose a P0845 Code?
The diagnosis process of the P0845 fault code is quite difficult most of the time. This is because code diagnosis can require quite a bit of knowledge surrounding your transmission, knowledge that most DIYers just don’t have. You may need to use a diagnostic flow chart, have access to technical service bulletins, and be able to look at a repair manual. These extra tools can make the diagnostic process more complex and add hours to diagnosis time. Rely on the qualifications of experts; get help from an automotive diagnostician for a more effective fix.
How Difficult Is It to Inspect a P0845 Code?
The inspection process, as with the diagnostic process, is often quite difficult. Again, this is an issue having to do with your transmission, which means you likely don’t have a lot of experience with it. If you’re in any way uncertain about your ability to manage the inspection process for the P0845 error code, don’t risk it. Answers from sites online probably won’t help; you should take your issue to a qualified professional to ensure that you get a solid fix.
Need Additional Help with Your P0845 Code?
Engine code P0845 is quite difficult to manage, so it’s very common to need additional help with this code. If you’re looking for assistance, you deserve to find an effective expert who can fix the problem you’re dealing with.
Your first step should be to find an auto repair shop in your area. Especially if you’re seeing issues with Limp Mode, a local auto repair shop is a great way to get a fix from highly-rated, verified experts without having to go too far out of your way.
You should also check out the OBD-Il database at KBB.com. This code regularly comes with other codes that can shine a light on the core issue, and this database can give you information about codes on your scan tool before you bring your vehicle in for assistance.
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