how to troubleshoot a P0700 code on my GMC Sierra T1XX (2019-Present)

Learn how to troubleshoot and fix P0700 transmission issues in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the vehicle is on a flat surface and secured with wheel chocks.

2. Inspect and Replace Transmission Fluid

• Sub-steps:
  • Remove the transmission fluid dipstick and check fluid level.
  • If the fluid is low, add the appropriate type of transmission fluid (refer to the owner's manual).
  • If the fluid is dark or smells burnt, proceed to replace the fluid.
• Tools Required: Socket set, transmission fluid pump, funnel, new transmission fluid.

3. Examine Wiring and Connectors

• Sub-steps:
  • Locate the TCM and visually inspect the connectors and wiring harness for any signs of wear or corrosion.
  • Disconnect the connectors and clean them with electrical contact cleaner if needed.
  • Reconnect and ensure a secure fit.
• Tools Required: Multimeter, electrical contact cleaner.

4. Test Transmission Solenoids

• Sub-steps:
  • Identify solenoids based on vehicle service manual specifications.
  • Use a multimeter to measure resistance across solenoid terminals.
  • Compare readings to manufacturer specifications; replace any solenoids that are out of range.
• Tools Required: Multimeter, socket set.

5. Reprogram TCM (if necessary)

• Sub-steps:
  • Connect a compatible OBD-II scanner capable of TCM reprogramming.
  • Follow the on-screen prompts to update or reprogram the TCM as needed.
  • Clear all error codes after reprogramming.
• Tools Required: OBD-II scanner.