P0505 obd2 code and how to check your idle speed control valve circuits

Checking P0505 code requires checking the idle control valve circuits and its wirings. Browse also our check engine codes list below so you will know the description of the obd2 codes

P0505     Engine Idle Air Control Fault

This code can be tested by using some basic test like testing for vacuum leaks to see if it is the source of erratic idle speed control valve malfunction. Take note that your iac control motor is the device that stabilizes your engine idle speed and if you have a vacuum leak, the iac motor will try to compensate for the leak. If you recall, vacuum leak will cause your engine rpm to rev up and it is the job of the iac motor to bring it down after being monitored by the ecm. However, if there is no leak, it is obviuos it is not a vacuum related problem but the iac motor itself. To test, disconnect the iac wiring connections and see if there is a change on the idle rpm. If not, replace the iac motor but do forget to follow the code resetting so the iac motor speed can go to the "relearn mode".

Servicing the idle speed control valve:

When servicing the idle speed control valve, remove any carbon soot and make sure the cone seal area is clean and in good condition by using a bit of fine steel wool on the cone. The carburetor cleaner can be sprayed into the port and a large Phillips head screwdriver wrapped in a rag to clean and remove a good amount of carbon soot from the port. To measure the pintle on the new IAC valve, make sure it is longer than 1 in. The common strategy is to open the idle air-bypass valve electrically to let some more air in for better cleaning.

Before reinstalling the idle control valve, measure the distance that the IAC valve is extended from the motor housing to the end of the IAC cone. It should not exceed 1-1/8" (or contact ATS for proper specs for different engines) or damage to the IAC valve may occur when installed again.

iac motor

This servicing assumes that the IAC motor has been checked for proper electrical resistance. (Shown in the picture on the left above is an IAC valve for FORD engine).

CODE     Meaning or Description

P046D     EGR Sensor A
P046E     EGR Sensor B
P046F     EGR Sensor B
P0470     Engine Exh press Sensor Ckt
P0471     Engine Exh press Sensor Ckt
P0472     Engine Exh press Sensor Ckt
P0473     Engine Exh press Sensor Ckt
P0474     Engine Exh press Sensor ckt
P0475     Engine Exh press Cntl Valve
P0476     Engine Exh press Cntl Valve
P0477     Engine Exh press Cntl Valve
P0478     Engine Exh press Cntl Valve
P0479     Engine Exh press Cntl Valve
P047A     Engine Exh Press Sensor Ckt
P047B     Engine Exh Press Sensor Ckt
P047C     Engine Exh Press Sensor Ckt
P047D     Engine Exh Press Sensor Ckt
P047E     Engine Exh Press Sensor Ckt
P047F     Engine Exh Press Control Valve
P0480     Engine Fan 1 Cntl ckt
P0481     Engine Fan 2 Cntl ckt
P0482     Engine Fan 3 Cntl ckt
P0483     Engine Fan Performance
P0484     Engine Fan Current
P0485     Engine Fan Power-Ground
P0486     EGR Sensor B Ckt
P0487     EGR Sensor A Ckt
P0488     EGR Sensor TPS A Ckt
P0489     EGR cntl Ckt
P048A     EGR cntl valve kt
P048B     EGR cntl valve ckt
P048C     EGR cntl valve ckt
P048D     EGR cntl valve ckt
P048E     EGR cntl valve ckt
P048F     EGR cntl valve ckt
P0490     EGR cntl ckt
P0491     Engine Air Injection System Flow (Bank 1)
P0492     Engine Air Injection System Flow (Bank 2)
P0493     Engine Fan Overspeed
P0494     Engine Fan Speed
P0495     Engine Fan Speed
P0496     Engine Evap Emission Purge Flow
P0497     Engine Evap Emission Purge Flow
P0498     Engine Evap Emission Control Ckt
P0499     Engine Evap Emission Control Ckt
P049A     EGR B Flow
P049B     EGR B Flow
P049C     EGR B Flow
P049D     EGR B Flow
P049E     EGR cntl position
P0500     Engine Vehicle speed
P0500     Engine Vehicle Speed
P0501     Engine Vehicle Speed Sensor
P0502     Engine Vehicle Speed Sensor
P0503     Engine Vehicle Speed Sensor
P0504     Vehicle Brake Switch variation
P0505     Engine Idle Air Cntl
P0506     Engine Idle Air cntl

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