Inspection Procedure

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

Check voltage between terminals PIG and PGND of EMPS ECU connector .
PREPARATION: Disconnect the connector from the EMPS ECU.

CHECK: Turn the ignition switch ON and measure the voltage between terminals PIG and PGND of EMPS ECU connector.

Fig 1: Locating EMPS ECU Terminals PIG & PGND
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Voltage: 9-14 V
1. OK: Check and replace EMPS ECU. See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE .
2. NG: Go to 2.
Check continuity between terminals PGND of EMPS ECU connector and body ground .
PREPARATION: Connect the connector back to the EMPS ECU.

CHECK: Measure the resistance between terminals PGND of EMPS ECU connector and body ground.

Fig 2: Locating EMPS ECU Terminal PGND
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Resistance: 1 Ohm or less
1. NG: Repair or replace harness or connector.
2. OK: Go to 3.
Check EMPS fuse .
PREPARATION: Remove the EMPS fuse from engine room R/B No. 3.

CHECK: Continuity of EMPS fuse.

Fig 3: Locating EMPS Fuse
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Continuity
1. NG: Check for short circuit in harness and all components connected to EMPS fuse. See Figure.
2. OK: Check for open and short circuit in harness and connector between EMPS ECU and battery. See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE .