P0847 Transmission fluid pressure sensor "B" circuit low

P0847 – OBD-II Trouble Code Technical Description

Trouble code P0847 indicates a low transmission fluid pressure sensor B circuit.

What does the fault code mean P0847?

Trouble code P0847 indicates a low signal in the transmission fluid pressure sensor “B” circuit. This means that the vehicle's control system has detected that the signal from the transmission fluid pressure sensor is below the expected level.

Automatic transmission vehicles use solenoid valves to regulate the hydraulic pressure needed to shift gears and lock up the torque converter. These valves are controlled by the transmission control module (PCM), which determines the required transmission fluid pressure based on various parameters such as engine speed, throttle position and vehicle speed. If the actual pressure does not match the required value due to a low signal in the sensor “B” circuit, this results in a P0847 code.

Possible reasons

Some possible reasons for the P0847 trouble code:

• Defective transmission fluid pressure sensor: The sensor itself may be damaged or miscalibrated, resulting in a low signal level in its circuit.
• Problems with wiring or connections: An incorrect connection or break in the wiring between the pressure sensor and the transmission control module can cause a low signal level and, as a result, P0847.
• Insufficient transmission fluid level: If the transmission fluid level is too low, it may cause insufficient pressure, which will be reflected in the sensor signal.
• Transmission fluid leak: Fluid leak problems can reduce system pressure, which can also cause a low sensor signal.
• Problems with the electrical system: Faults in the vehicle's electrical system, such as a short circuit or open circuit in the sensor circuit, may result in an insufficient signal.
• Malfunction of the automatic transmission control module (PCM): In rare cases, the problem may be due to a malfunction of the control module itself, which may not correctly interpret the signal from the sensor.

To accurately diagnose and fix the problem, it is recommended to contact a qualified auto mechanic or car service center.

What are the symptoms of a fault code? P0847?

The symptoms that may occur when the P0847 trouble code appears can vary depending on the specific problem and vehicle model, some of the possible symptoms are:

• Gear shifting problems: There may be delays, jerks or unusual noises when shifting gears.
• Incorrect behavior of the automatic transmission: The automatic transmission may shift into limp mode while remaining in one or more gears, which may reduce vehicle performance and controllability.
• Dashboard error: An error light or warning light may appear on the instrument panel indicating a problem with the transmission or transmission fluid pressure.
• Increased fuel consumption: Improper functioning of the gearbox can lead to increased fuel consumption due to ineffective gears.
• Unusual sounds or vibrations: Unusual sounds or vibrations may occur due to unstable pressure in the transmission system.

If you notice one or more of these symptoms, it is recommended that you contact a qualified auto mechanic to diagnose and repair the problem associated with the P0847 trouble code.

How to diagnose a fault code P0847?

The following approach is recommended to diagnose DTC P0847:

1. Check your dashboard: Check for any error lights or warning signs on the instrument panel related to transmission performance.
2. Use a diagnostic scanner: Connect the diagnostic scanner to your car's OBD-II port and read the error codes. If the P0847 code is confirmed, it indicates a problem with the transmission fluid pressure sensor.
3. Check the level and condition of the transmission fluid: Make sure the transmission fluid level is within the manufacturer's recommendations and is not contaminated or thickened. Low fluid level or contamination may be the cause of P0847.
4. Check wiring and connections: Inspect the wiring and connectors connecting the transmission fluid pressure sensor to the transmission control module. Make sure they are not damaged, broken or oxidized.
5. Check the pressure sensor itself: Check the transmission fluid pressure sensor for damage or leaks. You may also need to test its resistance or measure the voltage using a multimeter.
6. Additional diagnostics: If there are no obvious problems with the sensor and wiring, a more in-depth diagnosis may be required using specialized equipment or the assistance of a qualified auto mechanic.

After identifying the cause of error P0847, you should begin to eliminate it. This may include replacing the sensor, repairing or replacing damaged wires, and checking and servicing the transmission system.

Diagnostic errors

When diagnosing DTC P0847, the following errors may occur:

• Misinterpretation of symptoms: Similar symptoms may be associated with other transmission problems, so it is important to correctly interpret the symptoms and associate them with the P0847 trouble code.
• Faulty pressure sensor diagnosis: If the problem is not with the pressure sensor, but it is replaced without further diagnostics, this may result in unnecessary waste of time and money.
• Ignoring other problems: Trouble code P0847 can be caused not only by a faulty pressure sensor, but also by other problems such as a transmission fluid leak or an electrical problem. Ignoring these problems may result in the error reappearing.
• Incorrect calibration or setup: After replacing the pressure sensor, it may need to be calibrated or adjusted. Incorrect calibration may lead to incorrect readings and, as a result, the error will reappear.
• Insufficient diagnostics of wiring and connections: Wiring and connections can also be the source of the problem. Failure to properly diagnose their condition may result in a problem being missed or components being replaced unnecessarily.

To avoid these errors, it is important to carry out a thorough and systematic diagnosis and seek help from a qualified auto mechanic or transmission specialist if necessary.

How serious is the fault code? P0847?

Trouble code P0847 should be considered serious because it is related to the transmission fluid pressure sensor, several reasons why this trouble code can be considered serious:

• Potential transmission damage: Low transmission fluid pressure can cause unstable transmission operation. This can cause wear or damage to internal transmission components such as clutches, solenoids, and valves.
• Deterioration in vehicle performance: Transmission problems can result in incorrect gear shifting, jerking or delays when changing speeds. This may reduce the overall performance and driving comfort of the vehicle.
• Emergency risk: Improper functioning of the transmission can lead to unpredictable road conditions, which increases the risk of an accident for both the driver and others.
• Expensive repairs: Repairing or replacing transmission components can be expensive. Failure to properly manage the problem can result in increased repair costs and increased time spent rebuilding the transmission.

Overall, the P0847 trouble code should be taken seriously and diagnosed and repaired as soon as possible to prevent more serious transmission problems and ensure the safety and reliability of your vehicle.

What repair will help eliminate the code? P0847?

Troubleshooting DTC P0847 may require the following steps:

1. Replacing the transmission fluid pressure sensor: If the pressure sensor is faulty or giving incorrect readings, replacing it may solve the problem. Make sure the new sensor meets the manufacturer's specifications and is installed correctly.
2. Checking and repairing wiring and connections: Check the wiring and connectors connecting the transmission fluid pressure sensor to the transmission control module. Replace or repair damaged or broken wires and ensure that connectors are properly connected.
3. Checking and replacing transmission fluid: Make sure the transmission fluid level is within the manufacturer's recommendations and is not contaminated or thickened. Replace fluid if necessary.
4. Diagnose and repair other transmission problems: If the problem is not a sensor or wiring issue, other transmission components such as solenoids, valves, or hydraulic passages may need additional diagnosis and repair.
5. Programming and setupNote: After replacing a sensor or wiring, programming or tuning of the transmission control system may be required for the new components to operate correctly.

It is recommended that you have the P0847 code repaired and diagnosed by a qualified auto mechanic or transmission specialist to ensure that all necessary procedures are followed correctly and the problem is resolved.

How to Diagnose and Fix P0847 Engine Code - OBD II Trouble Code Explain

P0847 – Brand-specific information

List of interpretations of the P0847 fault code for various car brands:

1. Chevrolet:
   • P0847 – Transmission Fluid Pressure Sensor/Switch “B” Circuit Low.
2. Ford:
   • P0847 – Transmission Fluid Pressure Sensor/Switch “B” Circuit Low.
3. Toyota:
   • P0847 – Transmission Fluid Pressure Sensor/Switch “B” Circuit Low.
4. Honda:
   • P0847 – Transmission Fluid Pressure Sensor/Switch “B” Circuit Low.
5. Nissan:
   • P0847 – Transmission Fluid Pressure Sensor/Switch “B” Circuit Low.
6. BMW:
   • P0847 – Transmission Fluid Pressure Sensor/Switch “B” Circuit Low.
7. Mercedes-Benz:
   • P0847 – Transmission Fluid Pressure Sensor/Switch “B” Circuit Low.
8. Volkswagen:
   • P0847 – Transmission Fluid Pressure Sensor/Switch “B” Circuit Low.

These transcripts describe that the cause of the P0847 trouble code is a low signal in the transmission fluid pressure sensor or switch “B” circuit.