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Speedometer & Odometer Inaccurate

  1. Ensure Vehicle Control Module (VCM) is correctly calibrated for axle ratio and tire size. If calibration does not repair problem, go to next step. If calibration repairs problem, system is okay.
  2. Drive vehicle a known distance of at least 5 miles. Use scan tool and compare scan tool indicated speed to speedometer speed. Record initial and final odometer readings and actual distance driven. If scan tool and speedometer indications are within 4 MPH of each other, speedometer is operating to specification. Go to next step. If speedometer indications are not within 4 MPH of each other, replace instrument cluster.
  3. Divide actual distance driven by indicated distance driven. If result is .96-1.04, odometer accuracy is within tolerance. If result is not between .96-1.04, replace instrument cluster.
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