Low Data Rate System (LDR)

2009 Lincoln Navigator 4WDSECTION Low Data Rate System (LDR)

The LDR misfire monitor uses a low data rate CKP signal which indicates one position reference at 10 degrees before top dead center (BTDC) for each cylinder event. The PCM uses the CKP signal to calculate the crankshaft speed and acceleration for each cylinder. The crankshaft acceleration is then processed to detect a sporadic, single-cylider misfire patterns or multi-cylinder misfire patterns. The changes in overall engine RPM are removed by subtracting the median engine acceleration over a complete engine cycle. The resulting deviant cylinder acceleration values are used in evaluating misfire. Refer to the GENERIC MISFIRE PROCESSINGΒ  for more information.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.