Toyota Celica 2005 Repair Manual page 460

4 Check engine idle speed.
PREPARATION:
(a) Warm up the engine to the normal operating temperature.
(b) Switch off all the accessories.
(c) Switch off the A/C.
(d) Shift the lever into the neutral position.
(e) Connect the hand−held tester to the DLC3.
(f) Enter the following menus: DIAGNOSIS / ENHANCED OBD ll / ACTIVE TEST / ISC DUTY RATIO.
CHECK:
Check that the engine RPM varies when changing the ISC duty ratio.
OK:
Engine PRM fluctuates up and down in response to the ISC duty ratio variation.
NG
5 Check A/C signal circuit.
OK
6 Check blockage of IAC valve and passage to bypass throttle valve.
OK
2005 CELICA (RM1131U)
DIAGNOSTICS − ENGINE (1ZZ−FE)
OK Check for intermittent problems (See page
DI−3).
NG Repair or replace A/C signal circuit.
NG Replace IAC valve.
459
DI−261