TM System Malfunction in Nissan Leaf

Overview

• TM System Malfunction: A common warning in the first generation Nissan Leaf.
• Misleading: It suggests a transmission issue, but often relates to other problems.

Causes of TM System Malfunction

12V Battery Issues

• Primary Suspect: The small 12V battery, not the main EV battery.
• Symptoms: Control modules fail to determine shifter position; leads to warnings.
• Diagnosis:
  • Check battery with a load tester.
  • Charge using an external charger if necessary.
  • Replace if the battery is 4-5 years old.

Power Delivery Module (PDM)

• Secondary Suspect: If battery replacement doesn't resolve the issue.
• Role: DC-DC converter that charges the 12V battery from the EV battery.
• Failure: Results in no charging for the 12V battery when driving.
• Cost: New PDMs are expensive (~$4000).
• Solution: Consider buying a used PDM from a wrecked car with a warranty.

Factors Affecting PDM

• Thunderstorms: Charging during thunderstorms can damage the PDM.
• Recommendations: Avoid charging during thunderstorms or heavy rain.

Alternative Causes

• Wet Wiring: Can lead to TM system malfunctions.
• Challenges: Finding and drying corroded cables is complex.
• Recommendation: Seek professional help for diagnosis and repair.

Conclusion

• Proper maintenance and careful handling of the car, especially regarding the battery and charging practices, can prevent TM system malfunction warnings.