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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 set in memory for the item monitored below)
  • Misfire monitor
  • Exhaust gas recirculation (EGR) system monitor
  • Fuel system 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 more than 41°C (105°F).
  • 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 more than 33 g/sec (28 L/sec).
Judgment Criterion
  • The actual idle speed is less than the target idle speed by -100 r/min or less for 10 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • None
 
 
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 18 .
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
  • Throttle valve area is dirty.

 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle Communication Interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite Main Harness A
  • MB992747: V.C.I.-Lite USB Cable Short
  • MB992748: V.C.I.-Lite USB Cable Long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Using scan tool (M.U.T.-III), read the diagnostic trouble code (DTC).
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
(1) Connect scan tool (M.U.T.-III). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) .
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool (M.U.T.-III), read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the diagnostic trouble code other than P0506 set?
Refer to Diagnostic Trouble Code Chart .
Go to Step 2.
 
STEP 2. Check the throttle body. (throttle valve area)
Is the throttle valve area dirty?
Perform cleaning. Refer to Throttle body cleaning . Then go to Step 4.
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 .
(3) Check the diagnostic trouble code (DTC).
Is DTC P0506 set?
Replace the ECM (Refer to Removal and Installation ). Then go to Step 4.
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 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P0506 set?
Retry the troubleshooting.
The inspection is complete.