MPG ACURA RL KA9 1996 Service Repair Manual

Idle Contro l Syste m
System Descriptio n
The idl e spee d o f th e engin e is controlle d b y th e Idl e Ai r Contro l (IAC ) Valve .
Th e valv e change s th e amoun t o f ai r bypassin g int o th e intak e manifol d i n respons e t o electri c curren t controlle d b y th e
PCM . Whe n th e IA C Valv e is activated , th e valv e open s to maintai n th e prope r idl e speed .
VARIOU S
SENSOR S
INTAK E
MANIFOL D
IDLEADJUSTIN GSCREW
1. Afte r th e engin e starts , th e IA C valv e open s fo r a certai n time . Th e amoun t o f ai r i s increase d t o rais e th e idl e spee d
abou t 15 0 - 30 0 rpm .
2 . Whe n th e coolan t temperatur e i s low , th e IA C valv e i s opene d t o obtai n th e prope r fas t idl e speed . Th e amoun t o f
bypasse d ai r i s thu s controlle d in relatio n to th e engin e coolan t temperature .
3 . Whe n th e idl e spee d is ou t o f specificatio n an d th e sca n too l doe s no t indicat e Diagnosti c Troubl e Cod e (DTC ) P050 5 o r
P1508 , chec k th e followin g items :
• Adjus t th e idl e spee d (se e pag e 11-124 )
• Ai r conditionin g signa l (se e pag e 11-116 )
• AL T F R signa l (se e pag e 11-118 )
• Starte r switc h signa l (se e pag e 11-119 )
• Transmissio n rang e signa l (se e sectio n 14 )
• PS P switc h signa l (se e pag e 11-120 )
• Brak e peda l positio n switc h signa l (se e pag e 11-122 )
• Idl e ai r contro l therma l valv e (se e pag e 11-123 )
• Hose s an d connection s
• IA C valv e an d it s mountin g O-ring s
4 . I f th e abov e item s ar e normal , substitut e a known-goo d IA C valv e an d readjus t th e idl e spee d (se e pag e 11-124 ).
I f th e idl e spee d stil l canno t b e adjuste d t o specificatio n (an d th e sca n too l doe s no t indicat e DT C P050 5 o r P1508 ) afte r
IA C valv e replacement , substitut e a known-goo d PC M an d rechec k (se e pag e 11-42 fo r immobilize r information) . I f
sympto m goe s away , replac e th e origina l PCM .
IDLEAIRCONTRO LTHERMA LVALVE
IAC VALV E
FromPGM-F IMAINRELA Y
ENGIN E COOLAN T
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