P0787 – OBD-II DTC

OBD-II DTC P0787 – 3-4 Shift Malfunction

DTC P0787 meaning

DTC P0787 refers to a malfunction in the transmission system, specifically indicating a problem with the 3-4 shift. This code is triggered when the Engine Control Module (ECM) detects that the transmission is not shifting from third gear to fourth gear as expected. The issue may arise from various factors affecting the transmission’s performance.

DTC P0787 symptoms

Common symptoms associated with DTC P0787 include:

• Delayed or harsh shifting between gears
• Slipping transmission
• Check Engine Light illuminated
• Inability to shift into higher gears
• Unusual noises during shifting

DTC P0787 causes

Several factors can lead to the triggering of DTC P0787, including:

• Faulty transmission control module (TCM)
• Worn or damaged transmission components
• Low transmission fluid levels or fluid contamination
• Electrical issues such as short circuits or open circuits in wiring
• Faulty shift solenoids

DTC P0787 seriousness

DTC P0787 is considered a serious issue as it can affect the vehicle’s drivability and safety. If left unaddressed, it may lead to further transmission damage, resulting in costly repairs. It is advisable to diagnose and resolve the issue promptly to avoid potential breakdowns or accidents.

How to diagnose DTC P0787

To diagnose DTC P0787, follow these steps:

• Use an OBD-II scanner to confirm the presence of the code.
• Check for any additional DTCs that may provide more context.
• Inspect the transmission fluid level and condition.
• Examine the wiring and connectors related to the transmission control module.
• Test the shift solenoids for proper operation.
• Perform a road test to observe shifting behavior.

How to fix DTC P0787 step-by-step instructions

To fix DTC P0787, follow these step-by-step instructions:

1. Check and top off the transmission fluid if low.
2. Inspect the transmission fluid for contamination and replace if necessary.
3. Examine the wiring and connectors for damage or corrosion.
4. Test the shift solenoids and replace any that are faulty.
5. Replace the transmission control module if it is determined to be defective.
6. Clear the DTC using an OBD-II scanner and perform a road test to ensure the issue is resolved.

How to erase DTC P0787

To erase DTC P0787, follow these steps:

• Connect an OBD-II scanner to the vehicle’s diagnostic port.
• Turn on the ignition without starting the engine.
• Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
• Confirm the action to clear the codes.
• Disconnect the scanner and start the vehicle to check if the code reappears.

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