Test E Speedometers and/or Odometer(S) Are Inaccurate

TEST E: SPEEDOMETER IS INACCURATE

1. Plug a Tech 1 scan tool into the ALDL Connector at lower left of lip near steering column. With scan tool on and set to proper mode (RPM/Speed), operate vehicle at constant speeds. Observe the speedometer and scan tool display.

^ If they are in agreement + 2 mph, the Speedometer is good. Check for correct tire size and inflation, and axle ratio gear calibration

If all are correct, replace the VSS Buffer.

^ If scan tool and speedometer are not in agreement + 2 mph, go to Step 2.

2. Remove I/P Cluster. Connect a J 33431-B Signal Generator and instrument Panel Tester to printed circuit on underside of lip Cluster using a J 33431-9 Speedometer Edgeboard Connector. With the tester plugged in and set to ON, 54 mph, and 60 Hz, the Speedometer should read 54 mph + 2 mph.

^ If the Speedometer does not indicate properly, the Speedometer is to be sent to an approved A/C Repair Center for repair.

^ if the Speedometer operates properly, replace the VSS Buffer.