Test H: Speedometer Inoperative
- Using New Generation Star (NGS) or Worldwide Diagnostic System (WDS) tester, observe GEM PID VSS_GEM while driving vehicle between 0-55 MPH (0-89 km/h). If PID VSS_GEM value agrees with speedometer, go to next step. If PID VSS_GEM value does not agree with speedometer, see appropriate ANTI-LOCK article in BRAKES.
- Turn ignition switch to LOCK position. Disconnect Central Junction Box (CJB) connector C242b and instrument cluster connector C250b. Measure resistance between terminal No. 14 (Gray/Black wire) at CJB harness connector C242b and terminal No. 7 (Gray/Black wire) at instrument panel harness connector C250b. See Figure. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in Grey/Black wire and retest.
- Measure resistance between ground and terminal No. 22 (Gray/Black wire) at CJB harness connector C242b. If resistance is more than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short to ground in Gray/Black wire and retest.
- Turn ignition switch to RUN position. Measure voltage between ground and terminal No. 22 (Light Green/Black wire) at CJB harness connector C240b. If battery voltage is present, repair short to power in Light Green/Black wire and retest. If battery voltage is not present, go to next step.
- Measure resistance between ground and terminal No. 7 (Gray/Black wire) at instrument cluster wiring harness connector C250b. See Figure. If resistance is more than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short to ground in Gray/Black wire and retest.
- Disconnect 4 Wheel Anti-lock Brake System (4WABS) wiring harness connector C1040a. See Fig 1. Measure voltage between ground and terminal No. 16 (Gray/Black wire) at 4WABS harness connector C1040a. If battery voltage is present, repair short to power in Gray/Black wire and retest. If battery voltage is not present, go to next step.
- Measure voltage between ground and terminal No. 3 (Red/White wire) at instrument cluster harness connector C250b. See Figure. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Red/White wire and retest.
- Turn ignition switch to LOCK position. Check for corrosion, pushed out pins and connectors that are not connected properly. Repair any damage found and reconnect any loose connectors. Operate system. If problem does not exist, system is operating properly at this time. Clear any DTCs and retest. If problem exists, replace instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION.
Courtesy of FORD MOTOR CO.