Speedometer/Odometer Inaccurate
- Ensure Vehicle Speed Sensor Buffer is correctly calibrated for axle ratio and tire size. If axle ratio and tire size are okay, test drive vehicle over a known distance of at least 5 miles. Using scan tool, compare scan tool displayed speed to speedometer. Record initial and final odometer readings and actual distance driven.
- If scan tool and speedometer are within 4 MPH of each other, accuracy is within specification. Go to next step. If scan tool and speedometer are not within 4 MPH of each other, replace IPC.
- Divide actual distance driven by indicated distance driven. If calculated result is .96-1.04, odometer accuracy is within specification. If calculated result is not .96-1.04, replace IPC.
NOTE:
Before performing following test, ensure no problems exist in vehicle speed sensor, vehicle speed sensor buffer. See appropriate ENGINE PERFORMANCE and/or BRAKE SYSTEM - ANTI-LOCK article.