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 RLY and PGND of EMPS ECU connector .
PREPARATION: Remove the EMPS ECU with connectors still connected.

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

Fig 1: Locating EMPS ECU Terminals RLY & PGND
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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 EMPS relay .
PREPARATION: Remove the EMPS relay from the engine room R/B No. 3.

CHECK: The continuity between each terminal of the EMPS relay.

OK: See Fig 3.

Fig 2: Testing EMPS Relay
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Fig 3: EMPS Relay Specifications (W/O Power Applied)
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CHECK
1. Apply battery positive voltage between terminals 1 and 2. See Fig 3.
2. Check the continuity between the terminals.
OK: Terminals 3 and 5 have continuity .
1. NG: Replace EMPS relay.
2. OK: Go to 3.
Check ECU-B fuse .
PREPARATION: Remove the ECU-B fuse from instrument panel J/B.

CHECK: the continuity of ECU-B fuse.

Fig 4: Locating ECU-B Fuse
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OK: Continuity
1. NG: Check for short in harness and all components connected to ECU-B fuse. See Figure.
2. Go to .
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 .