What is CID 645 & How to Solve It?

What is CID 645:

CID 645 refers to an issue with the vehicle's transmission system, particularly with the transmission control module (TCM). The ECM detects that the TCM is malfunctioning, which can lead to poor shifting, loss of acceleration, or failure to engage gears properly.

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Why This Happens:

• Faulty transmission control module (TCM).
  
• Shorted or damaged wiring in the TCM circuit.
  
• Low transmission fluid levels.
  
• Loose or corroded connectors.
  
• ECM failure to properly interpret TCM data.
  
  

How to Fix It:

1. Inspect the TCM for faults or damage.
   
2. Check wiring and connectors for visible damage or corrosion.
   
3. Ensure proper transmission fluid levels and condition.
   
4. Reprogram or replace the TCM if necessary.
   
5. Perform a full system diagnostic check to ensure proper transmission operation.
   
   

How to Avoid It Before It Happens:

• Perform regular transmission system checks.
  
• Inspect transmission fluid levels regularly.
  
• Keep connectors clean and secure.
  
• Perform routine diagnostics to monitor TCM health.
  
• Clue’s fleet management software helps monitor transmission systems and prevent shifting or performance issues.