What is CID 977 & How to Solve It?

What is CID 977:

cid 977 refers to a problem in the crankshaft position sensor circuit. the ecm detects missing or erratic signals, affecting ignition timing and overall performance.

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Why This Happens:

• defective crankshaft position sensor.
  
• broken or shorted wiring.
  
• corroded connectors near the crank pulley.
  
• damaged reluctor ring.
  
• poor ecm signal grounding.
  
  

How to Fix It:

1. inspect the crankshaft sensor and reluctor wheel.
   
2. test voltage and waveform output.
   
3. clean connectors and recheck grounding.
   
4. replace sensor if resistance is out of range.
   
5. retime engine if necessary.
   
   

How to Avoid It Before It Happens:

• maintain clean sensor areas free of debris.
  
• perform diagnostic waveform checks during maintenance.
  
• ensure proper grounding of ecm circuits.
  
• clue’s equipment maintenance services track sensor reliability and reduce unexpected engine stalls.