If you’re experiencing transmission shift point issues or engagement quality problems, it might be necessary to clear the memory in your PCM (Powertrain Control Module) completely. In this guide, I’ll show you the steps to do it effectively.
Start by disconnecting the negative cable from the battery and insulate it to prevent contact. Then, remove the positive cover and use a jumper wire with alligator clips to connect the positive terminal to the body and the engine components. Make sure the negative cable remains disconnected and insulated throughout this process. Leave the setup for about five to ten minutes to drain the capacitors in the PCM.
After the waiting period, remove the jumper wire, reconnect the negative cable, and proceed to relearn the shift points or fuel trims in the PCM.
It is important to note that simply disconnecting the negative cable or using a scan tool may not completely clear the PCM memory, making the capacitor draining process essential.
Once the memory is cleared, it’s recommended to learn the idle values. Reconnect the negative cable, turn the key on, and wait for about 10 seconds before starting the vehicle. Let it idle for five to ten minutes with all accessories turned off to ensure the idle values are learned properly.
When going for a test drive, shift through the gears from 1st to 5th at a light acceleration to allow the PCM to learn the shift points effectively. Additionally, after the initial learning process, avoid aggressive driving behaviors for the next few days to ensure proper relearning of shift points.
By following these steps, you can effectively clear the memory in your PCM and relearn shift points or fuel trims from scratch, allowing for smoother transmission performance and resolving related issues.
How can I clear the memory in my PCM completely?
To clear the memory in your PCM completely, you will need to disconnect the negative terminal and then drain the capacitors in the PCM. After disconnecting the negative terminal, unscrew it to 8 mil, pull it aside, and put a rag or insulator around it. Next, pull the positive cover off and take a jumper wire with alligator clips, making sure the negative is off and insulated. Place one end of the jumper wire on the positive terminal and the other end on the terminal that goes to the body and the engine. After 5 to 10 minutes, remove the jumper wire, reconnect the negative terminal, and proceed to learn the shift points or fuel trims from scratch.
What should I do after clearing the PCM memory?
After clearing the PCM memory, you should reconnect the negative cable, turn the key on for 10 seconds to learn the stop value of the throttle body, and then start the car and let it idle for 5 to 10 minutes with all accessories off. Following this, go on a test drive to ensure proper learning of the shift points.
When should I conduct the test drive after clearing the PCM memory?
The test drive should involve shifting through the gears 1st through 5th with light acceleration, allowing the transmission to learn the shift points properly. It is advisable to conduct the test drive after completing the initial learning process as per the instructions provided.