OBD scan tool (excluding hand-held tester):

Check VSV for ACIS (See INSPECTION ).
1. NG: Replace VSV for ACIS.
2. OK: Go to next step.
Check voltage between terminal ACIS of ECM connector and body ground.
PREPARATION:
1. Remove the engine room ECM cover.
2. Turn the ignition switch ON.
CHECK:

Measure the voltage between terminals ACIS of the ECM connector and body ground.

Fig 1: Measuring Voltage Between Terminals ACIS Of ECM Connector & Body Ground
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK:

Voltage: 9 to 14 V
1. NG: Go to step 4 .
2. OK: Go to next step.
Check for open and short in harness and connector between EFI main relay (Marking: EFI) and ECM (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).
1. NG: Repair or replace harness or connector.
2. OK: Go to next step.
Check vacuum hose.
CHECK:
1. Check that the vacuum hoses are connected correctly.
2. Check that the vacuum hoses are not loose or disconnected.
3. Check the vacuum hoses for cracks, holes or damage.
1. NG: Repair or replace vacuum hose.
2. OK: Go to next step.
Check intake air control valve (See ACOUSTIC CONTROL INDUCTION SYSTEM (ACIS) ).
1. NG: Replace intake air control system.
2. OK: Replace ECM (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE .)