P0506

DTC P0505 / P0506 / P0507: Idle Air Control (IAC) System Malfunction / RPM Lower than Expected / RPM Higher than Expected

System / Wiring Diagram










DTC Detecting Condition and Trouble Area (DTC P0505)






DTC Confirmation Procedure

NOTE:

Check to make sure that the following conditions are satisfied when using this DTC confirmation procedure.

- Intake air temp.: Between -14 °C and 70 °C (6.8 °F and 158 °F)
- Altitude (barometric pressure): 2020 m, 6650 ft or less (540 mmHg, 72 kPa or more)
- Transmission gear shift lever is shifted in "Neutral" for M/T (in "P" position for A/T)
- Electric load (lighting, heater blower, rear defogger, etc.) and A/C are turned OFF.

1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and warm up to normal operating temperature (80 °C - 110 °C, 176 °F - 230 °F).
4) Run engine at idle speed (600 - 1000 r/min.) for 5 min. or more.
5) Check DTC and pending DTC.

DTC Troubleshooting

1.
Was "Engine System Check" performed?
YES
Go to Step 2.
NO
Go to Engine System Check Engine System Check.

2. Idle speed check

Check idle speed / idle air control duty referring to Adjustments Idle Speed / Idle Air Control (IAC) Duty Inspection and Adjustment.

Is check result as specified?
YES
Go to Step 3.
NO
Go to Step 4.

3. Vehicle speed sensor signal check

Is vehicle speed displayed on scan tool when driving vehicle?
YES
Intermittent trouble.
If OK, substitute a known-good ECM and recheck.
NO
Go to Step 4 in DTC P0500 diag. flow table.

4. Air intake system check

Check air intake system for clog and air inhaling.
Check fast idle plunger length referring to Fast Idle Control System On-Vehicle Inspection Fast Idle Control System On-Vehicle Inspection.

Are the check result satisfactory?
YES
Go to Step 5.
NO
Repair or replace.

5. Idle air control valve operation check

Check idle air control valve for operation referring to Idle Air Control (IAC) Valve Operation Check Idle Air Control (IAC) Valve Operation Check.

Is check result satisfactory?
YES
Go to Step 7.
NO
Go to Step 6.

6. Idle air control valve check

Check idle air control valve for resistance and operation referring to Initial Inspection and Diagnostic Overview Idle Air Control (IAC) Valve Inspection.

Is check result satisfactory?
YES
"BLK/RED" or "GRN/RED" circuit open or short.
If wire and connections are OK, substitute a known-good ECM and recheck.
NO
Clean or replace idle air control valve.

7. Check parts or system which can cause engine low or high idle.

- EGR valve malfunction (leakage)
- EVAP system malfunction
- Accessory engine load
- Engine mechanical (Engine compression)

Are they in good condition?
YES
Go to Step 8.
NO
Repair or replace.

8. Idle air adjusting screw check

Adjust idle speed and idle air control duty referring to Adjustments Idle Speed / Idle Air Control (IAC) Duty Inspection and Adjustment.

Are specified idle speed and idle air control duty obtained?
YES
Idle air adjusting screw maladjusted.
NO
Clog of idle air passage.
If OK, substitute a known-good ECM and recheck.