P0802 Open circuit for the automatic transmission control system warning lamp request
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P0802 – OBD-II Trouble Code Technical Description
Trouble code P08 indicates an open circuit in the automatic transmission control system warning lamp request circuit.
What does the fault code mean P0802?
Trouble code P0802 indicates an open in the automatic transmission control lamp request circuit. This means that the powertrain control module (PCM) has received a malfunction signal from the transmission control system (TCS), which requires the Malfunction Indicator Lamp (MIL) to turn on.
Possible reasons
Some of the possible causes of the P0802 trouble code are:
- Broken or damaged wiring: The problem may be caused by an open or damaged wiring connecting the powertrain control module (PCM) to the malfunction indicator lamp (MIL).
- Malfunction lamp defect or malfunction: If the Malfunction Indicator Lamp (MIL) itself is not functioning correctly due to a defect or malfunction, it may cause the P0802 code.
- Problems with the powertrain control module (PCM): A malfunction in the PCM, such as software corruption or failure, can also cause this DTC to appear.
- Transmission Control System (TCS) Problems: Malfunctions in the transmission control system, such as solenoids or sensors, can cause an erroneous trouble signal that results in a P0802 code.
- Problems with electrical connections: Poor connections or corrosion on the electrical connections between the PCM and the malfunction indicator lamp can cause this error.
These reasons may vary depending on the specific vehicle and its design. For an accurate diagnosis, it is recommended that you consult a repair manual or a qualified mechanic.
What are the symptoms of a fault code? P0802?
For trouble code P0802, symptoms may include the following:
- Malfunction indicator lamp (MIL) is on or flashing: This is one of the most obvious signs of a problem. When the P0802 code appears, the MIL on the instrument panel may illuminate or flash, indicating a problem with the transmission control system.
- Gear shifting problems: Difficulty shifting may occur, including delays, jerking, or incorrect shifting.
- Poor transmission performance: The transmission may be operating less efficiently due to the problem that caused the P0802 code to appear.
- Other fault codes appear: Sometimes the P0802 code may be accompanied by other trouble codes related to the transmission control system or electrical components.
These symptoms may manifest differently depending on the specific problem and the characteristics of the vehicle.
How to diagnose a fault code P0802?
To diagnose DTC P0802, follow these steps:
- Checking the Malfunction Indicator Lamp (MIL): First, make sure that the malfunction indicator lamp (MIL) on the instrument panel is working properly. If the MIL does not illuminate when the ignition is turned on or does not flash when a trouble code appears, this may indicate a problem with the lamp itself or its connections.
- Using the Diagnostic Scanner: Use the vehicle's diagnostic scanner to scan the transmission control system (TCS) and PCM for trouble codes. If a P0802 code is detected, you should proceed with more detailed diagnostics.
- Checking electrical connections and wiring: Inspect all electrical connections and wiring connecting the PCM and the malfunction indicator lamp. Make sure the connections are tight and there is no damage to the wires or corrosion on the contacts.
- Checking solenoids and sensors: Check the condition of the solenoids and sensors in the transmission control system. Make sure they work correctly and have no problems.
- PCM diagnostics: If necessary, perform additional diagnostics on the PCM to ensure it is operating properly. This may include checking the PCM software and its connections.
- Additional tests: Depending on the specific circumstances and nature of the problem, additional tests and inspections may be required, such as voltage and resistance testing, and inspection of transmission mechanical components.
If you are unsure of your automotive repair skills or experience, it is recommended that you contact a qualified mechanic or auto repair shop for professional diagnosis and repair.
Diagnostic errors
When diagnosing DTC P0802, the following errors may occur:
- Skipping the malfunction indicator lamp test: Sometimes the technician may not check the Malfunction Indicator Lamp (MIL) functionality, which can lead to misinterpretation of the problem.
- Insufficient checking of electrical connections and wiring: If the technician does not sufficiently inspect the electrical connections and wiring, a problem due to broken or damaged wiring may be missed.
- Skipping PCM and other component diagnostics: Certain components such as the PCM or sensors may also cause the P0802 code. Failure to diagnose these components may result in an incorrect determination of the cause of the problem.
- Incorrect interpretation of scanner data: Incorrectly reading data from the diagnostic scanner or incorrectly interpreting it can lead to erroneous conclusions about the causes of the P0802 code.
- Wrong repair strategy: If a technician chooses the wrong repair strategy based on an incorrect diagnosis, it may result in unnecessary component replacements or problems that remain faulty.
- Skipping additional tests and checks: Some additional tests and inspections may be necessary to fully identify the cause of the P0802 code. Omitting them can lead to incomplete diagnosis and incorrect repairs.
To avoid these errors, it is important to follow the correct diagnostic procedure and conduct a comprehensive analysis of all possible causes.
How serious is the fault code? P0802?
Trouble code P0802 is not directly safety critical, but it does indicate problems with the automatic transmission control system. Although the vehicle may continue to drive, the presence of this fault may cause transmission instability and poor vehicle performance.
If the P0802 code is not detected and corrected promptly, it can lead to further transmission degradation and other serious vehicle problems. In addition, the presence of a malfunction can affect fuel consumption and the overall operating economy of the vehicle.
Therefore, although a P0802 code is not an immediate safety concern, it is recommended that you have a qualified mechanic or auto repair shop diagnose and repair it to avoid further problems and ensure normal transmission operation.
What repair will help eliminate the code? P0802?
Resolving the P0802 trouble code depends on the specific issue causing it, but there are a few general repair steps that may help resolve the code:
- Checking and replacing the Malfunction Indicator Lamp (MIL): If the problem is related to the indicator lamp itself, it can be replaced.
- Checking and repairing wiring and electrical connections: Inspect the wiring and electrical connections between the PCM and the malfunction indicator lamp. Any breaks, damage or corrosion found must be repaired or replaced.
- Diagnosis and PCM replacement: If the problem is with the PCM receiving incorrect data, it may require diagnosis or replacement.
- Checking and repairing transmission components: Certain transmission problems, such as faulty solenoids or sensors, can also cause a P0802 code. Check their functionality and, if necessary, replace faulty components.
- Programming or updating PCM software: Sometimes the problem may be related to the PCM software. Check for available software updates or perform PCM programming if necessary.
- Additional tests and checks: Depending on your specific situation, additional tests and inspections may be required to identify and correct the problem.
It is important to have the problem professionally diagnosed and repaired to avoid further problems with your vehicle. If you are not confident in your skills, it is better to contact a qualified mechanic or auto repair shop.
P0802 – Brand-specific information
Trouble code P0802 can have different meanings depending on the specific make of the car, several possible meanings for different brands:
- Ford: P0802 may stand for “Transmission Control System MIL Request Circuit Open.”
- Chevrolet / GMC: P0802 can be interpreted as “Transmission Control System MIL Request Circuit Open.”
- Toyota: For Toyota, code P0802 may mean “Transmission Control System MIL Request Circuit Open.”
- Honda: On Honda, P0802 may stand for “Transmission Control System MIL Request Circuit Open.”
- BMW: For BMW, P0802 may mean “Transmission Control System MIL Request Circuit Open.”
Please refer to the specifications and documentation for your specific vehicle make and model for a more accurate interpretation of the P0802 trouble code.
