What is CID 988 & How to Solve It?

What is CID 988:

cid 988 refers to a fault in the engine speed sensor (rpm sensor) circuit. the ecm detects irregular or missing signals, affecting timing, fuel injection, and idle performance.

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Why This Happens:

• defective engine speed sensor.
  
• damaged or shorted wiring harness.
  
• dirty or metallic debris on sensor tip.
  
• loose connectors.
  
• failed ecm processing.
  
  

How to Fix It:

1. clean debris from the sensor tip.
   
2. check voltage and waveform during engine crank.
   
3. inspect connectors for corrosion or loose fits.
   
4. repair or replace damaged wiring.
   
5. replace the sensor if faulty.
   
   

How to Avoid It Before It Happens:

• keep sensor areas clean and dry.
  
• inspect rpm sensors during oil changes.
  
• perform diagnostic waveform checks periodically.
  
• clue’s equipment maintenance services track rpm sensors to ensure accurate timing and fuel delivery.