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Speedometer Inaccurate

  1. Verify condition, drive vehicle at a specified speed and measure time required to drive one mile. Determine if speedometer is accurate in accordance with time required to travel a measured mile. See SPEEDOMETER ACCURACY SPECIFICATIONS table.
    SPEEDOMETER ACCURACY SPECIFICATIONS

    Indicated Speed Time
    40 km/h 81-98 Sec.
    60 km/h 55-64 Sec.
    80 km/h 42-47 Sec.
    100 km/h 33-37 Sec.
    30 MPH 109-130 Sec.
    40 MPH 83-95 Sec.
    50 MPH 67-75 Sec.
    60 MPH 56-62 Sec.
  2. If speedometer is accurate, ensure speedometer accuracy is checked under conditions which problem reportedly occurred. If measured time at specified speed is inconsistent (low in one speed and high in another), replace speedometer. Adjust odometer mileage on replacement speedometer and install odometer sticker on driver-door pillar to indicate speedometer replacement. If measured time for specified speeds is always high or low, proceed to step 3).
  3. Checking tire size & rear axle ratio, ensure both tires are the same size and are properly inflated. Adjust tire size and pressure if necessary.
  4. If both tires are the same size and properly inflated, check axle ratio. Axle ratio is stamped on metal tag attached to rear differential. Ensure tire size is correct for axle ratio. See DETERMINING TIRE SIZE, AXLE RATIO & DRIVE GEAR APPLICATION.
  5. If axle ratio and tire size are correct, proceed to step 6). If tire size is not correct for axle ratio, adjust tire size and repeat step 1).
  6. Checking drive gears, ensure transmission and speed sensor gears contain correct number of teeth and color code in accordance with axle ratio. See DETERMINING TIRE SIZE, AXLE RATIO & DRIVE GEAR APPLICATION.
  7. If drive gears are incorrect, replace drive gears and repeat step 1). If drive gears are correct, replace speedometer and recheck speedometer accuracy. Adjust odometer mileage on replacement speedometer and install odometer sticker on driver-door pillar to indicate speedometer replacement.
DETERMINING TIRE SIZE, AXLE RATIO & DRIVE GEAR APPLICATION

Tire Size Axle Size No. Teeth (1) Color (2) No. Teeth
P215/70R15 2.73 17 Green 8
P215/70R15 3.08 17 Green 7
P215/70R15 3.27 18 Gray 7
P215/70R15 3.55 19 Tan 7
225/70HR15 2.73 17 Green 8
225/70HR15 3.08 19 Tan 8
225/70HR15 3.27 20 Orange 8
225/70HR15 3.55 19 Tan 7
(1) The number of teeth on the drive gear on the transmission.
(2) The number of teeth on the drive gear on the speed sensor.
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