how to fix P0700 code in GMC Sierra T1XX (2019-Present)

Learn how to diagnose and fix P0700 transmission control system malfunction in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Transmission Fluid

• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Remove the transmission fluid pan using a socket set.
  3. Drain the old fluid into a suitable container.
  4. Replace the transmission filter if applicable.
  5. Reinstall the transmission pan with a new gasket, tightening to manufacturer specifications.
  6. Fill the transmission with the recommended fluid type (check the owner’s manual for specifications).

3. Repair or Replace TCM

• Sub-steps:
  1. Locate the transmission control module, usually found under the dashboard or near the transmission.
  2. Disconnect the wiring harness from the TCM.
  3. Remove the TCM by unscrewing it from its bracket.
  4. If testing indicates a faulty TCM, install a new one, ensuring it matches the vehicle's specifications.
  5. Reconnect the wiring harness securely.

4. Check and Replace Transmission Control Solenoids

• Sub-steps:
  1. Identify the location of the transmission control solenoids, usually accessible through the transmission pan.
  2. Remove any necessary components to gain access.
  3. Use a multimeter to test each solenoid for proper operation.
  4. Replace any faulty solenoids with new ones, following manufacturer specifications for installation.

5. Final Assembly

• Sub-steps:
  1. Reinstall any components that were removed during the procedure.
  2. Reconnect the battery and ensure all electrical connections are secure.
  3. Start the vehicle and check for any leaks around the transmission area.