Description of the P0887 fault code.
OBD2 Error Codes

P0887 Transmission Power Relay (TCM) Control Circuit High

26.05.2022 /

P0887 – OBD-II Trouble Code Technical Description

Trouble code P0887 indicates a high signal level in the transmission power relay (TCM) control circuit.

What does the fault code mean P0887?

Trouble code P0887 indicates a high signal level on the transmission power relay (TCM) control circuit. This means that the transmission controller (TCM) is receiving too much voltage on this circuit. Typically, the TCM only receives power when the ignition switch is in the ON, Crank, or Run position. This circuit is usually equipped with a fuse, fuse link or relay. Often the PCM and TCM are powered by the same relay, albeit on separate circuits. Each time the engine is started, the PCM performs a self-test on all controllers. If the input voltage signal exceeds the normal level, a P0887 code will be stored and the malfunction indicator may illuminate. In some models, the transmission controller may go into emergency mode, which means travel is only available in 2-3 gears.

Fault code P0887.

Possible reasons

Possible reasons for DTC P0887:

  1. Malfunction in the transmission power relay (TCM Relay): Burnt contacts, corrosion, or other damage can cause the relay to malfunction, causing a high signal level in the control circuit.
  2. Wiring problems: Opens, shorts, or damage to the wiring, connections, or connectors associated with the power relay control circuit can cause a high signal level.
  3. Transmission Control Module (TCM) Problems: Faults in the TCM itself can result in unusually high voltage in its control circuit.
  4. Problems with other power system components: For example, problems with the alternator or battery can cause incorrect voltage in the electrical system, including the TCM control circuit.
  5. Malfunctions in other vehicle systems: For example, a short circuit or other problems in the ignition system or engine management system can also cause P0887.
  6. TCM/PCM Software: Rarely, an incorrect calibration or software update of the TCM or PCM can result in improper operation and therefore a high signal level in the power relay control circuit.

What are the symptoms of a fault code? P0887?

Symptoms when trouble code P0887 is present may include the following:

  • Transmission problems: You may experience incorrect gear shifting, delays in shifting, uneven shifting, or unavailability of certain gears.
  • Speed ​​and operating mode limitation: The car may be speed limited or run only in limp mode, which means only a limited number of gears are available, for example only 2nd or 3rd gear.
  • When the fault indicator appears: A malfunction indicator may come on on the instrument panel, indicating problems with the transmission control system.
  • Lost performance: The vehicle may experience loss of performance due to improper operation of the transmission, which may result in increased fuel consumption or poor performance.
  • Rough or unusual transmission behavior: In some cases, the transmission may react more harshly or unusually when shifting gears, which may be related to the P0887 code.

It is important to note that symptoms may vary depending on the specific vehicle model and operating conditions. If the above symptoms occur, it is recommended that you contact a qualified auto mechanic for diagnosis and repair.

How to diagnose a fault code P0887?

The following steps are recommended to diagnose DTC P0887:

  1. Using an OBD-II scanner: Connect the OBD-II scanner to the car and read the fault codes. Make sure the P0887 code is actually present and not random or false.
  2. Checking symptoms: Evaluate transmission performance and note any symptoms that indicate problems with the transmissions or transmission control system.
  3. Checking electrical connections: Inspect the wiring and connectors associated with the transmission power relay control circuit. Make sure all connections are secure and not damaged or oxidized.
  4. Power relay test: Check the condition of the transmission power relay, making sure it is functioning properly and activating when needed.
  5. TCM and PCM Diagnostics: Use diagnostic equipment to check the operation of the transmission control module (TCM) and engine control module (PCM). Make sure they are functioning correctly and do not require replacement or reprogramming.
  6. Checking electrical circuits: Perform a thorough inspection of electrical circuits, including wires, sensors and other components related to transmission control.
  7. Check for other possible causes: Consider the possibility of other causes, such as problems with power components or other vehicle systems, that could cause the P0887 code.
  8. Additional tests and diagnostics: If necessary, perform additional tests and diagnostics to identify other potential problems associated with the P0887 trouble code.

It is important to remember that diagnosing and repairing vehicle electrical systems requires experience and knowledge, so if you do not have experience in this area, it is recommended that you contact a professional auto mechanic for diagnosis and repair.

Diagnostic errors

When diagnosing DTC P0887, the following errors may occur:

  • Skip checking electrical connections: Insufficient inspection of the wiring, connectors, and connections in the power relay control circuit can result in undiagnosed electrical component problems.
  • Faulty power relay: Ignoring the possibility of a faulty transmission power relay may result in an incorrect diagnosis. It is important to check the operation of the relay and make sure it is working properly.
  • Misinterpretation of symptoms: Some symptoms, such as improper shifting or limited operation, may be related to other transmission or electrical system problems other than P0887.
  • Incorrect interpretation of OBD-II scanner data: Failure to correctly interpret the data received from the OBD-II scanner may lead to an incorrect determination of the cause of the P0887 code or incorrect actions to resolve it.
  • Skipping additional diagnostic tests: Not performing all of the necessary additional tests or diagnostic checks may result in other problems associated with the P0887 code being missed, which may make it more difficult to resolve.
  • Wrong solution to the problem: Ruling out the possibility of other causes than electrical problems for P0887 may result in replacing undamaged components or making unnecessary repairs.

It is important to keep in mind that diagnosing the P0887 code requires a careful and methodical approach, as well as a good understanding of the vehicle's electrical systems.

How serious is the fault code? P0887?

Trouble code P0887 is serious because it indicates a high signal level in the transmission power relay (TCM) control circuit. This problem can lead to improper transmission operation, limited vehicle performance, and potentially dangerous driving conditions. If this DTC is ignored or left unresolved, it can lead to serious consequences such as:

  • Limitation of vehicle functionality: The transmission may be limited to only operating in certain gears, which may make it difficult to control and affect vehicle performance.
  • Loss of control of the vehicle: Changing gears incorrectly or not having certain gears available can cause you to lose control of your vehicle while driving, increasing the risk of an accident.
  • Increased wear of parts: Improper operation of the transmission can lead to increased wear on parts, which in turn may require costly repairs or replacement.
  • Increased fuel consumption: Improper shifting of gears or constant operation in limited mode can result in increased fuel consumption, which will negatively affect fuel economy.

Based on this, the P0887 trouble code should be considered a serious problem that requires immediate attention and diagnosis by a qualified auto mechanic to prevent possible consequences and ensure safe operation of the vehicle.

What repair will help eliminate the code? P0887?

Troubleshooting the P0887 trouble code depends on the specific causes of this error. The following are possible repair methods:

  1. Checking and replacing the power relay: If the reason lies in a malfunction of the transmission power relay, it is necessary to check its condition and, if necessary, replace it with a new, working one.
  2. Checking and repairing electrical connections: Inspect the wiring, connectors, and connections associated with the power relay control circuit. Identify and repair breaks, corrosion, or other damage that could result in high signal levels.
  3. TCM or PCM Diagnosis and Replacement: If the problem is due to a faulty transmission control module (TCM) or engine control module (PCM), these modules may need to be replaced or reprogrammed.
  4. Checking and replacing electrical components: It's possible that some other electrical components, such as sensors, fuses, or wires, may also be damaged and require replacement.
  5. Diagnostics of other vehicle systems: Perform additional tests and diagnostics to rule out problems in other vehicle systems that could cause the power relay control circuit to be high.
  6. Programming or software update: In rare cases, the problem can be resolved by reprogramming or updating the TCM or PCM software.

It is important to remember that successfully resolving the P0887 code requires proper diagnosis and determination of the source of the problem. If you do not have experience working with vehicle electrical systems, it is recommended that you contact a qualified auto mechanic or service center for diagnosis and repair.

How to Diagnose and Fix P0887 Engine Code - OBD II Trouble Code Explain

P0887 – Brand-specific information

Trouble code P0887 can occur on various brands of cars, a list of some of them with their meanings:

As with the previous list, it is important to note that the transcripts above may vary slightly depending on the specific model and year of the vehicle. For more accurate information, it is recommended to consult the repair or service manual for your specific vehicle.

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