PPS ECU Inspection

1. Raise and support vehicle.
2. On ES 250 models, remove safety pad as outlined under DASH PANEL.
3. On LS 400 models, remove instrument panel No. 1 as outlined under DASH PANEL.
4. Start engine.

Fig. 21 Power Steering ECU Inspection:

5. Measure voltage of ECU using a suitable voltmeter between ECU terminals SOL - and GND, Fig. 21.
6. Standard voltage is 0.32-0.44 volts on ES 250 and LS 400, 0.43-0.56 volts on ES 300 and 0.3-0.5 volts on SC 300 and SC 400.
7. Place transmission in gear and while running at 37 mph, measure voltage between ECU terminals SOL - and GND.
8. Standard voltage is voltage measured in step 5 minus 0.04-0.18 volts on ES 250 and LS 400, 0.08-0.22 volts on ES 300, 0.05-0.18 volts on SC 300 and 0.07-0.2 volts on SC 400. If sum equals zero volts, try another ECU.