Diagnostic Aids
WARNING: This page is about a different car, the 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
Short-term and long-term fuel trim value should be within plus or minus 25 percent of each other at 176°F (80°C). ECM controls voltage of AFR+, AFL+, AFR- and AFL- terminals at ECM to a fixed voltage (3.3 volts at AFR+ and AFL+ terminal; 3.0 volts at AFR- and AFL- terminal). It is impossible to confirm A/F sensor output voltage without using Toyota hand-held tester or scan tool. A/F sensor output voltage on scan tool is displayed at one fifth the voltage of that displayed on a Toyota hand-held tester. Using hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.