DTC P0505: Idle Control System Malfunction

NOTE: If DTC P1508 or P1509 is set, trouble shoot DTC P0505 last.

Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Allow engine to idle. Check engine speed with no loads (headlights, blower motor, rear defogger, radiator cooling fan and A/C off). See IDLE SPEED SPECIFICATIONS table. If engine speed is not within specification, go to next step. If engine speed is within specification, problem is intermittent. System is okay at this time.
If engine speed is 550 RPM or less, go to next step. If engine speed is more than 550 RPM, turn ignition off. Remove intake air duct from throttle body. Start engine and allow it to idle. Place finger on lower port in throttle body. If engine speed does not decreased, check for vacuum leaks and ensure throttle valve is completely close. Repair as necessary. If engine speed decreases, adjust base idle speed to specification. See ON-VEHICLE ADJUSTMENTS article. If idle speed will not adjust to specification, replace IAC valve.
On D16Y7 engine with A/T, disconnect 3-pin connector from IAC valve. If engine speed does not increase, replace IAC valve. If idle speed increases, adjust base idle speed to specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS article. If idle speed will not adjust to specification, clean throttle body ports. On all except D16Y7 engine with A/T, disconnect 2-pin connector from IAC valve. If engine speed does not decrease or engine does not stall, replace IAC valve. If idle speed decreases or engine stalls, adjust base idle speed to specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS article. If idle speed will not adjust to specification, clean throttle body ports.

IDLE SPEED SPECIFICATIONS

Application			RPM
D16A2
USA			650-750
Canadian			700-800
D16Y5
A/T Or CRV			650-750
M/T			620-720
D16Y7 & D16Y8
USA
A/T Or CRV			650-750
M/T			620-720
Canadian			700-800