"C" & "K" Series
- Check rear axle ratio and rear tire size. If rear axle ratio and tire size are the same as when vehicle was manufactured, check vehicle speed sensor circuit. See VEHICLE SPEED SENSOR TEST in this article.
- If rear axle ratio and/or tire size are different than when vehicle was manufactured, check digital ratio adapter programming clip. See INSTRUMENT PANEL CALIBRATION SPECIFICATIONS at end of this article.
- Check for brake Code 9 and inoperative speedometer/odometer or ECM Code 24 with correctly operating speedometer/odometer. If ECM code 24 is set and speedometer/odometer operate, check vehicle speed sensor buffer output. See, in this article BUFFER OUTPUT DIAGNOSIS .
- If brake Code 9 is set and speedometer/odometer are inoperative, check vehicle speed sensor buffer power input. See, in this article, BUFFER POWER DIAGNOSIS . Also check vehicle speed sensor circuit. See VEHICLE SPEED SENSOR TEST in this article.