Pinpoint Test A - Speedometer Inaccurate

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

   Indicated Speed	Seconds
   40 km/h	82-100
   60 km/h	55-65
   80 km/h	42-49
   100 km/h	35-39
   30 MPH	111-132
   40 MPH	85-98
   50 MPH	68-78
   60 MPH	57-65

2. If speedometer is accurate, ensure speedometer accuracy is checked under conditions at 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. Install odometer sticker on driver door pillar to indicate speedometer replacement. If measured time for specified speeds is always high or low, go 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 differential. Ensure tire size is correct for axle ratio. See Figure.
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 Fig 1.
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. Install odometer sticker on driver door pillar to indicate speedometer replacement.

Fig 1: Determining Tire Size, Axle Ratio & Drive Gear Application