how to diagnose P0700 code in my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, fluid pump.
• Disconnect the negative battery cable to prevent electrical shorts.
• Allow the vehicle to cool down if the engine has been running.

2. Inspect and Replace Transmission Fluid

• Sub-steps:
  1. Locate the transmission fluid dipstick or fill plug.
  2. Remove the dipstick or fill plug and check fluid levels; add fluid if low.
  3. If fluid is dark or has a burnt smell, drain the fluid using a fluid pump.
  4. Replace with the manufacturer-recommended transmission fluid (Toyota ATF WS).
  5. Reinstall the dipstick or fill plug and ensure it is secure.

3. Repair or Replace Wiring/Connectors

• Sub-steps:
  1. Inspect the wiring harness leading to the TCM and transmission for frays or breaks.
  2. Clean any corroded connectors using electrical contact cleaner.
  3. Repair any damaged wires using solder and heat-shrink tubing.
  4. If connectors are severely damaged, replace them with OEM parts.

4. Test and Replace TCM (if necessary)

• Sub-steps:
  1. Using a multimeter, check the voltage at the TCM connector according to specifications from the service manual.
  2. If voltage is incorrect, trace the issue back to wiring or fuses.
  3. If TCM is faulty, remove it by unscrewing the mounting bolts and disconnecting the wiring harness.
  4. Install a new TCM by reversing the removal steps, ensuring all connections are secure.

5. Final Check

• Reconnect the negative battery cable.
• Clear the P0700 code using the OBD-II scanner.
• Test drive the vehicle to ensure proper operation.