my Honda Civic 10th Generation (2016-2021) has a check engine light with code P0700

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, transmission fluid dipstick.
• Safety Warnings: Disconnect the battery before working on the electrical system to avoid short circuits.

2. Check and Replace Transmission Fluid

1. Remove the Transmission Fluid Fill Cap: Locate and remove the fill cap to access the fluid.
2. Check Fluid Level: Insert the transmission fluid dipstick, remove it, and check the fluid level. If low, add fluid as necessary.
3. Inspect Fluid Condition: If the fluid is dark or has a burnt smell, prepare to replace it.
4. Drain Old Fluid: Place a drain pan under the transmission and drain the fluid by removing the drain plug.
5. Replace Fluid Filter (if applicable): Remove the transmission pan, replace the fluid filter, and install a new gasket.
6. Refill with New Fluid: Reinstall the drain plug and refill the transmission with the manufacturer-recommended fluid type and quantity.

3. Repair or Replace TCM

1. Remove TCM: Locate the TCM, disconnect the wiring harness, and unbolt the TCM from its mounting position.
2. Inspect TCM: Check for any visible damage or corrosion. If the module appears faulty, replace it with a new unit.
3. Reinstall TCM: Position the new TCM, secure it with bolts, and reconnect the wiring harness.

4. Clear Codes and Test Drive

1. Clear DTCs: Use the OBD-II scanner to clear any stored trouble codes.
2. Test Drive: Drive the vehicle to ensure proper shifting and that the check engine light does not reappear.