1998 Honda Civic Code P0505

MAZEDAVE

MEMBER
1998 HONDA CIVIC
4 CYL
2WD
AUTOMATIC
125,000 MILES

Q; I recently changed timing belt & water pump. I noticed when reassembled the car was idling at 1000-1100 rpm, a tad high. Soon after we started getting the P0505 code. Any suggestions?

Saturday, November 22nd, 2008 AT 7:19 AM

1 Reply

KHLOW2008

MECHANIC
41,814 POSTS

Hi mazedave,

DTC P0505 - IDLE CONTROL SYSTEM MALFUNCTION

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

1. 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. On Canadian models, set parking brake and ensure headlights are off. Using OBD-II scan tool, check engine speed with no loads (headlights, blower motor, rear defogger, radiator cooling fan and A/C off).
See IDLE SPEED SPECIFICATIONS.
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.

2. If engine speed is 550 RPM or less, go to next step. If engine speed is not 550 RPM or less, disconnect IAC valve connector. On A/T equipped vehicles and D16Y7 engine, if engine speed does not increase, replace IAC valve. On A/T equipped vehicles and D16Y7 engine, if engine speed increases, adjust base idle speed to specification. On D16Y5 and D16Y8 engines with M/T, if engine speed does not decrease or engine does not stall, replace IAC valve. On D16Y5 and D16Y8 engines with M/T, if engine speed decreases or engine stalls, adjust base idle speed to specification.
See ADJUSTMENTS article.
On all models, if idle speed will not adjust to specification, clean throttle body ports. If idle speed still will not adjust, replace IAC valve.

3. Remove air intake duct from throttle body. Place a finger on upper port in throttle body. If engine speed does not decrease, check for vacuum leaks and ensure throttle valve is completely closed. Repair as necessary. If idle speed decreases, adjust base idle speed to specification.

See ADJUSTMENTS article.

If idle speed will not adjust to specification, replace IAC valve.

IDLE SPEED SPECIFICATIONS
Application _____________________________RPM
D16Y5 Engine CVT - - - - - - - - - - - - - - - - - - 650-750
D16Y5 & D16Y8 Engines M/T - - - - - - - - - - - 400-500
D16Y7 & D16Y8 Engines A/T (1) - - - - - - - - - 650-750
D16Y7 M/T (1) 620-720 D16Y7 & D16Y8 (2) - - -700-800

(1) USA. (2) Canadian.

From what you have done, I suspect the timing belt hasnot been installed correctly and you should recheck the markings before proceeding with other rectifications.