P0845 Malfunction of the electrical circuit of the transmission fluid pressure sensor “B”

P0845 – OBD-II Trouble Code Technical Description

Trouble code P0845 indicates a malfunction in the transmission fluid pressure sensor "B" circuit.

What does the fault code mean P0845?

Trouble code P0845 indicates that the automatic transmission control module (PCM) has detected abnormal voltage readings from the transmission fluid pressure sensor B. This error code is often accompanied by other codes related to torque converter lockup, shift solenoid valve, gear slippage, gear ratio or lockup. Various sensors are used to determine the required pressure for the transmission to operate. If the fluid pressure sensor does not detect pressure correctly, it means that the required transmission fluid pressure cannot be achieved. In this case, error P0845 occurs.

Possible reasons

Some possible reasons for the P0845 trouble code:

• Defective or damaged transmission fluid pressure sensor.
• Incorrect or damaged wiring, connections or connectors associated with the pressure sensor.
• Malfunction in the transmission hydraulic system.
• Problems with the engine control module (PCM) itself.
• Incorrect transmission fluid pressure due to various reasons such as a leak, clogged filter or defective hydraulic components.

What are the symptoms of a fault code? P0845?

Symptoms for DTC P0845 may include the following:

• Uneven or jerky gear shifting.
• Difficult gear shifting.
• Loss of power.
• The Check Engine indicator appears on the instrument panel.
• Limitation of transmission operation in emergency mode.
• Changes in transmission performance characteristics.

How to diagnose a fault code P0845?

To diagnose trouble code P0845, follow these steps:

1. Check connections and wiring: First of all, check the condition of all electrical connections and wires associated with the transmission fluid pressure sensor. Make sure that all contacts are securely connected and show no signs of corrosion or oxidation.
2. Check the transmission fluid pressure sensor: Use a multimeter to check the resistance and voltage at the transmission fluid pressure sensor. Make sure it functions correctly and produces the correct signals.
3. Check the level and condition of the transmission fluid: Make sure the transmission fluid level is within the recommended range and check for contamination or impurities.
4. Error scanning: Use an OBD-II scanner to check for other error codes in the engine management system. Additional codes may provide additional information about the problem.
5. Check vacuum lines and valves: Check the condition and efficiency of the vacuum lines and valves associated with the transmission control system.
6. Check the engine control module (PCM): If all other components and systems appear fine, the problem may be with the PCM itself. In this case, professional diagnosis and repair may be required.

Diagnostic errors

When diagnosing DTC P0845, the following errors may occur:

• Misinterpretation of symptoms: Some symptoms, such as changes in transmission performance, may be incorrectly interpreted as problems with the transmission fluid pressure sensor. This may result in the sensor being replaced unnecessarily.
• Wiring problems: The error may be due to improper operation of the electrical system or wiring. Undetected damaged wires or faulty contacts can lead to incorrect diagnostic conclusions.
• Malfunction of other components: Such symptoms can be caused not only by a faulty transmission fluid pressure sensor, but also by other problems in the transmission or engine management system. For example, problems with valves, gaskets, or the transmission itself can present with similar symptoms.
• Incorrect interpretation of scanner data: Inexperienced technicians may misinterpret the scanner data, which may result in incorrect diagnosis and replacement of faulty components.
• Problems with the PCM itself: In rare cases, the error may be caused by a faulty engine control module (PCM) or other electronic components associated with the transmission control system.

How serious is the fault code? P0845?

Trouble code P0845 indicates a problem with the transmission fluid pressure sensor. While this problem is not critical to immediate driving safety, it can cause serious problems with the transmission's performance, which can ultimately lead to vehicle failure. Therefore, it is recommended that you take immediate action to diagnose and repair the problem after the P0845 code appears to avoid further transmission damage and related problems.

What repair will help eliminate the code? P0845?

Troubleshooting trouble code P0845 involves the following steps:

1. Checking the transmission fluid pressure sensor: Start by checking the sensor itself for damage, corrosion, or corrosion. Check its connections for short circuit or open signals.
2. Inspect Wiring and Connectors: Check the wiring from the transmission fluid pressure sensor to the PCM for damage, opens, or shorts. Carefully inspect and check the condition of all connectors.
3. Sensor Replacement: If the transmission fluid pressure sensor is found to be faulty, replace it with a new one.
4. Checking and replacing transmission fluid: Check the level and condition of the transmission fluid. Replace it if necessary and make sure the level is correct.
5. Checking and Reprogramming the PCM: If all of the above measures do not resolve the problem, the PCM may need to be checked and, if necessary, reprogrammed.
6. Additional Tests: In some cases, additional tests may need to be performed to identify other transmission-related problems.

After completing these steps, it's worth resetting the trouble code and doing a thorough test drive to make sure the problem is resolved. If the code does not appear again and the transmission operates properly, the problem is considered resolved.

How to Diagnose and Fix P0845 Engine Code - OBD II Trouble Code Explain

P0845 – Brand-specific information

Code P0845 can be found on various brands of cars, some of them with their decodings:

• Ford: Transmission fluid pressure sensor/switch "B" circuit malfunction.
• Chevrolet: Transmission fluid pressure sensor/switch "B" circuit malfunction.
• Dodge: Transmission fluid pressure sensor/switch "B" circuit malfunction.
• Honda: Transmission fluid pressure sensor/switch “B” – circuit malfunction.
• Toyota: Transmission fluid pressure sensor/switch “B” – circuit malfunction.

Consult the specific repair manuals or service books for your vehicle brand to get more detailed information about which specific sensor or sensor corresponds to the P0845 code in your specific case.