What Codes Will This Page Cover?
This page will cover the following diagnostic codes and the issues they represent:
- P0841 Transmission Fluid Pressure Sensor/Switch “A” Circuit
- P0842 Transmission Fluid Pressure Sensor/Switch “A” Circuit Low
- P0843 Transmission Fluid Pressure Sensor/Switch “A” Circuit High
- P0844 Transmission Fluid Pressure Sensor/Switch “A” Circuit Intermittent
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What Is the P0841 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
Diagnostic codes P0841 to P0844 refer to issues within a vehicle’s transmission fluid pressure sensor or switch “A” circuit. These issues can range from a lack of ability to sense transmission fluid pressure to sensors picking up very high, low, or intermittent pressure in transmission fluid. These issues primarily impact a vehicle’s ability to properly shift gears but can lead to other problems if left unchecked.
More Information on P0841, P0842, P0843, and P0844 Diagnostic Codes
Diagnostic codes P0841, P0842, P0843, and P0844 refer specifically to problems with a vehicle’s transmission fluid pressure sensor/ switch “A” circuit. Newer cars manufactured after 1996 often have multiple transmission oil switches, and when one fails, it will register one of these codes or simply check the check engine light. Here’s what each code indicates in particular:
- P0841 Transmission Fluid Pressure Sensor/Switch “A” Circuit
P0841 indicates there is an issue with the transmission fluid pressure sensor or switch “A” circuit’s performance. More specifically, this code indicates that the sensor has found out-of-range pressure or abnormalities in the transmission fluid pressure within that sensor’s circuit.
- P0842 Transmission Fluid Pressure Sensor/Switch “A” Circuit Low
P0842 indicates issues within the transmission fluid pressure sensor or switch “A” circuit’s performance. In particular, it indicates low system operating pressure or low voltage transmission mainline pressure within the system.
- P0843 Transmission Fluid Pressure Sensor/Switch “A” Circuit High
P0843 indicates issues with transmission fluid pressure picked up by the sensors or the switch “A” circuit. More specifically, this code indicates that the sensor has picked up the signal of a high-voltage reading.
- P0844 Transmission Fluid Pressure Sensor/Switch “A” Circuit Intermittent
P0844 is an error code that indicates issues within the transmission sensor of switch “A” circuit. Specifically, it indicates that the system input is unable to consistently match the normal operating voltages recorded in the memory of the vehicle’s PCM/TCM.
These error codes are generic trouble codes that apply to all vehicles in the OBD-II system, in particular those made after 1996. These vehicles include but are not limited to, Chevrolet, GM, Toyota, Honda, and Ford models.
What Are the Symptoms of a P0841 Code?
The symptoms associated with these error codes can vary depending on which code your vehicle displays. However, since the transmission of a vehicle uses hydraulic pressure that is controlled by solenoids and, in turn, the PCM to provide torque and shift gears, issues with shifting are the most common symptom associated with these codes. As well as displaying the check engine light, a car displaying a P0841, P0842, P0843, or P0844 code may experience:
- Loss of shifting capabilities
- Slipping transmission
- Decreased fuel efficiency
- Harsh gear shifting
- Disengagement or lack of engagement from torque converter clutch
These symptoms are more likely once the issue has progressed; however, the first sign is likely to be the activation of the check engine light.
What Are Some Causes of a P0841 Code?
The most common causes of codes P0841, P0842, P0843, and P0844 are:
- Dirty or contaminated transmission fluid
- Low transmission fluid
- Mechanical transmission failures
- A faulty PCM or TCM (uncommon)
How Serious Is the P0841 Code?
These codes indicate the presence of a very serious problem that should be addressed quickly. If left to grow unchecked, then transmission issues will make a vehicle unsafe and, eventually, completely undrivable.
Can I Still Drive with a P0841 Code?
Driving a car that is showing a P0841, P0842, P0843, or P0844 code may be fine at first, but transmission issues will make it increasingly difficult and dangerous to operate the car as it struggles to change gears or generate torque. As such, you should remedy the underlying causes of these codes as soon as possible and only drive the car as much as is necessary to have it repaired.
How Easy Is It to Diagnose a P0841 Code?
It is fairly easy to identify whether there may be some issues with a car’s transmission as the color and consistency of the transmission fluid often changes. The most common mistakes made when diagnosing transmission issues based on these codes include replacing the high-pressure pump rather than the electrical components, sensors, or solenoids.
How Difficult Is It to Inspect a P0841 Code?
Beyond checking the physical transmission fluid, the inspection process becomes more complex. Inspecting the electrical and physical components can be more difficult. Many of the components in the transmission system are small and delicate.
Need Additional Help with Your P0841 Code?
Transmission fluid is incredibly important to the proper and safe functioning of a vehicle; issues with the pressure sensors and switches can cause serious mechanical damage and malfunction quickly. If you want to make sure such a sensor issue doesn’t escalate, then it is a good idea to investigate and repair the underlying causes.
If you are unable to address transmission issues personally, then it is advisable to find a reputable repair shop in your local area with the help of Kelley Blue Book. Experts have all the tools that they need to diagnose, identify, and repair transmission issues.
If you are committed to a DIY approach, however, then the KBB OBD-II database is a reliable and informative source that will give you insight into what is happening within your car. This resource can also aid in identifying secondary and tertiary issues that may arise.
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