Instrument Cluster Test 4A - Speedometer Not Operating Properly
NOTE:
Perform INSTRUMENT CLUSTER TEST 1A
before proceeding. For connector terminal ID, see CONNECTOR IDENTIFICATION
and WIRING DIAGRAM. Perform TEST VER-1A
after each repair.
CAUTION:
Always turn ignition switch to OFF position prior to disconnecting any module connector. Ensure all connectors are clean and tight.
- Using scan tool, access ELECTRO/MECH CLUSTER menu. Read cluster type (US or Metric). If cluster type does not match application, replace instrument cluster circuit board. If cluster type matches application, go to next step.
- Using scan tool, check for Powertrain Control Module (PCM) diagnostic trouble codes. If trouble code(s) exist, repair as required. See the appropriate TESTS W/CODES in the ENGINE PERFORMANCE section. For 4.0L 6-Cylinder, see: TESTS W/O CODES - 4.0L 6-CYL . For 5.2L V8, see: TESTS W/O CODES - 5.2L V8 . If no trouble code(s) exist, go to next step.
- Using scan tool, actuate speedometer gauge. If speedometer moves to it's calibration points, go to step 5). See GAUGE CALIBRATION POINTS table under INSTRUMENT CLUSTER TEST 2A. If speedometer does not move to it's calibration points, go to next step.
- Remove instrument cluster. Loosen screws holding speedometer to circuit board. Ensure screws do not touch circuit board. Using an ohmmeter, measure resistance across speedometer gauge coils No. 1 and 2. See Fig 1 . If resistance across each coil is not about 280 ohms, replace speedometer. If resistance across each coil is about 280 ohms, replace circuit board.
- Raise and support vehicle. Remove speedometer pinion gear from transmission. Count number of teeth on pinion gear and compare to specification. See SPEEDOMETER PINION GEAR APPLICATION table. Replace pinion gear if gear teeth do not match tire size and axle ratio. If correct pinion gear is installed, go to next step.
- Reinstall pinion gear. Start engine. Place transmission in gear. If speedometer moves to it's calibration points, system is operating properly at this time. If speedometer still does not move to it's calibration points, replace powertrain control module.
SPEEDOMETER PINION GEAR APPLICATION
| Tire Size | Axle Ratio | Pinion Teeth |
|---|---|---|
| P215/75R15 | 3.55 | 35 |
| P215/75R15 | 3.73 | 36 |
| P225/70R16 | 3.55 | 34 |
| P225/70R16 | 3.73 | 36 |
| P225/75R15 | 3.55 | 34 |
| P225/75R15 | 3.73 | 36 |
| P245/70R15 | 3.55 | 34 |
| P245/70R15 | 3.73 | 35 |