P0506

DTC P0506: Idle Control System RPM Lower Than Expected

TECHNICAL DESCRIPTION

- The amount of air taken in during idling is regulated by the opening and closing of the throttle valve.
- The ECM checks the difference between the actual engine speed and the target engine speed.

DESCRIPTIONS OF MONITOR METHODS

Difference between actual and target idle speed is over the specified value.

MONITOR EXECUTION

Continuous

MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)

- Misfire monitor
- Fuel system monitor
- Vehicle speed signal monitor
Sensor (The sensor below is determined to be normal)

- Mass airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Throttle position sensor

DTC SET CONDITIONS

Logic Flow Chart






Check Conditions

- Under the closed loop idle speed control.
- The engine coolant temperature is 41°C (105°F) or more.
- Battery positive voltage is higher than 10 volts.
- Barometric pressure is higher than 76 kPa (22.4 in.Hg).
- Intake air temperature is higher than -10°C (14°F).
- 3 seconds have elapsed from the start of the previous monitoring.
- Target air flow rate is 29 g/sec (24 L/sec) or more.
Judgement Criterion

- The actual idle speed is more than 100 r/min lower than the target idle speed for 10 seconds.

FAIL-SAFE AND BACKUP FUNCTION

- None

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 18 Monitors, Trips, Drive Cycles and Readiness Codes .

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)

- Throttle valve area is dirty.
- ECM failed.


DIAGNOSIS

Required Special Tools

- MB991958: Scan tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A

STEP 1. Using scan tool MB991958, read the diagnostic trouble code (DTC).





CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK"
(OFF) position before connecting or disconnecting scan tool MB991958.

(1)Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to the "ON" position.
(3)Set scan tool MB991958, read the DTC.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the diagnostic trouble code other than P0506 set?

YES Refer to Diagnostic Trouble Code Chart Multiport Fuel Injection (MFI).

NO Go to Step 2.

STEP 2. Check the throttle body. (throttle valve area)

Q. Is the throttle valve area dirty?

YES Perform cleaning. Refer to Throttle body cleaning Throttle Body Cleaning.
Then go to Step 4.
NO Go to Step 3.
STEP 3. Replace the throttle body assembly.

(1)Replace the throttle body assembly

(2)Carry out test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 18 Monitors, Trips, Drive Cycles and Readiness Codes.

(3)Check the diagnostic trouble code (DTC).

Q. Is DTC P0506 set?

YES Replace the ECM (Refer to, Removal and Installation Removal and Replacement).
Then go to Step 4.
NO The inspection is complete.
STEP 4. Test the OBD-II drive cycle.

(1)Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 18 Monitors, Trips, Drive Cycles and Readiness Codes.

(2)Check the diagnostic trouble code (DTC).

Q. Is DTC P0506 set?

YES Retry the troubleshooting.
NO The inspection is complete.