LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 1997 >> LS 400 >> Repair and Diagnosis >> Electrical >> Gauges >> Instrument Panel >> System Testing >> Test 7: Speedometer Does Not Work
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test 7: Speedometer Does Not Work

  1. Backprobe ECM connector terminal SPDM. See Fig 1. Check frequency while driving vehicle. Frequency should be 42.5 Hz at 32 MPH (60 KM/H), and 68.4 Hz at 60 MPH (88 KM/H). Output wave can be verified using oscilloscope. If frequency is not as specified, go to step 4). If frequency is as specified, turn ignition off. Check continuity between connector "E" terminal No. 11 and No. 12 of ECM and connector "D" terminal No. 8 of instrument panel. Repair as needed. Go to next step.
  2. Check continuity of instrument panel power source unit. See Fig 2. Continuity should exist between A and b6, B and a13, C and b5. Replace instrument panel power source unit if continuity does not exist.
  3. Disconnect all instrument panel connectors. Check resistance between D8 and F5. See Fig 3. If resistance is 6300-6800 ohms, replace speedometer. If resistance is not 6300-6800 ohms, replace power source unit.
  4. Check VSS circuit resistance between terminal No. SP2+ and SP- of ECM. See Fig 1. Resistance should be 560-680 ohms. If resistance is okay, replace ECM. If resistance is not as specified, go to next step.
  5. Check VSS resistance between terminal No. 1 and No. 2. Resistance should be 560-680 ohms. Replace as needed. If VSS is okay, repair wiring between ECM and VSS.
Fig 1: Identifying ECM Terminals
G97C07309Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Identifying Instrument Panel Circuit Plate Terminals
G97E07310Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 3: Identifying Power Source Unit Terminals
G97G07311Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002