Test L: Malfunction In Average Fuel Consumption/Instantaneous Fuel Consumption/Possible Running Distance Display
WARNING: This page is about a different car, the 2003 Lexus ES 300 and 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
- Confirm that the speedometer, tachometer and fuel receiver gauge are normal, then check the circuit. See Fig 1.
- Check the combination meter assembly (TAU, TAUB, SPD):
- Disconnect the C8 connector from the combination meter assembly. See Figure. Check the voltage (TAUB signal). Turn the ignition switch to ON. Measure the voltage (10-14 volts) between terminal No. C8-12 of the combination meter assembly connector and body ground. Check the voltage (TAU signal). Turn the ignition switch ON. Measure the voltage (10-14 volts) between terminal No. C8-21 of the combination meter assembly connector and body ground. Check the signal waveform (TAU signal). Connect the oscilloscope to the terminal No. C8-21 of the combination meter assembly connector and body ground. See TERMINAL C8-21 SIGNAL WAVEFORM table. Start the engine. Check the signal waveform. See Fig 2.TERMINAL C8-21 SIGNAL WAVEFORM
Item Contents Tool Setting 10 V/ DIV, 20 ms/ DV Vehicle Condition Engine Idle Speed - If the TAUB signal is not OK, go to the next step. If the TAU signal is not OK, go to appropriate FUEL SYSTEM article. If the signals are OK, check and replace the combination meter assembly. See COMBINATION METER SAFETY PAD SUB-ASSEMBLY under REMOVAL & INSTALLATION.
- Disconnect the C8 connector from the combination meter assembly. See Figure. Check the voltage (TAUB signal). Turn the ignition switch to ON. Measure the voltage (10-14 volts) between terminal No. C8-12 of the combination meter assembly connector and body ground. Check the voltage (TAU signal). Turn the ignition switch ON. Measure the voltage (10-14 volts) between terminal No. C8-21 of the combination meter assembly connector and body ground. Check the signal waveform (TAU signal). Connect the oscilloscope to the terminal No. C8-21 of the combination meter assembly connector and body ground. See TERMINAL C8-21 SIGNAL WAVEFORM table. Start the engine. Check the signal waveform. See Fig 2.
- Inspect the continuity in the IGN fuse. If the fuse is OK, repair or replace the wiring harness or connector. If the fuse is not OK, replace the fuse.