OBD II scan tool (excluding hand held tester):

WARNING: This page is about a different car, the 2004 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.

Check voltage between terminals VPA and EPA, and VPA2 and EPA2 of ECM connector.

PREPARATION:

Remove the glove compartment (see COMPONENTS ).
Turn the ignition switch ON.

CHECK:

Measure the voltage between terminals VPA and EPA, and VPA2 and EPA2 of the ECM connector.

OK:

ACCELERATOR PEDAL VOLTAGE

Accelerator Pedal	Voltage
Accelerator Pedal	VPA - EPA	VPA2 - EPA2
Released	0.5 to 1.1 V	1.5 to 2.9 V
Depressed	2.5 to 4.6 V	3.9 to 5.5 V

Fig 1: Checking Voltage Between Terminals VPA (+) And EPA (-), And VPA2 (+) And EPA2 (-)

OK : Replace ECM (see COMPONENTS ).
NG : Go to next step.

Check for open and short in wire harness in VCPA, VCP2, VPA, VPA2, EPA and EPA2 circuits between ECM and accelerator pedal position sensor (see HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE in INTRODUCTION article).
1. OK : Repair or replace.
2. NG : Replace accelerator pedal assembly (see SFI article).