how to fix P0700 code on 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 the repair.
• Ensure the vehicle is parked on a level surface and the engine is turned off.
• Disconnect the battery to prevent any electrical shorts.

2. Fluid Check and Replacement

1. Check Fluid Level: Remove the transmission dipstick and check the fluid level; add fluid if necessary.
   • Tools Required: Transmission dipstick, funnel.
2. Inspect Fluid Condition: If the fluid is dark or smells burnt, proceed to replace it.
3. Fluid Replacement:
   • Drain the old transmission fluid by removing the drain plug.
   • Replace the transmission filter if applicable.
   • Reinstall the drain plug and refill with new transmission fluid according to manufacturer specifications.
   • Tools Required: Socket set, oil catch pan.

3. Electrical Inspection

1. Inspect Wiring: Check all wiring harnesses connected to the TCM for fraying, corrosion, or loose connections.
   • Repair any damaged wiring or connectors found.
2. Test Solenoids: Use a multimeter to check solenoid resistance; replace any solenoids that do not meet specifications.
   • Tools Required: Multimeter.

4. TCM Reprogramming or Replacement

1. Reprogram TCM: If no hardware issues are found, check for available software updates for the TCM and reprogram it using a compatible scan tool.
2. Replace TCM: If the TCM is found to be faulty, remove the old unit and install a new TCM.
   • Tools Required: Socket set, torque wrench (use manufacturer specifications for torque values).