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DTC P050A: Cold Start Idle Air Control System Performance
 
 
 
 
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
  • Fuel system monitor
  • Vehicle speed sensor monitor <M/T>
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 between 7°C (45°F) and 41°C (106°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).
  • More than 3 seconds have elapsed from the previous monitoring.
Judgment Criterion
  • The actual idle speed is less than -100 r/min lower than the target idle speed for 10 seconds.
 
 
Check Conditions
  • Under the closed loop idle speed control.
  • The engine coolant temperature is between 7°C (45°F) and 41°C (106°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).
  • More than 3 seconds have elapsed from the previous monitoring.
Judgment Criterion
  • Actual idle speed has continued to be higher than the target idle speed by 200 r/min or more 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.
  • Throttle body assembly failed.
  • ECM failed.
 
 
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) Read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the diagnostic trouble code other than P050A set?
Refer to Diagnostic Trouble Code Chart .
Go to Step 2.
 
STEP 2. Check the intake system vacuum leak.
Are there any abnormalities?
Repair or replace it. Then go to Step 4.
Go to Step 3.
 
STEP 3. Check the throttle body. (throttle valve area)
Is the throttle valve area dirty?
Perform cleaning. Refer to Throttle Body (Throttle Valve Area) Cleaning . Then go to Step 5.
Go to Step 4.
 
STEP 4. 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 P050A set?
Replace the ECM (Refer to Removal and Installation ). Then go to Step 5.
The inspection is complete.
 
STEP 5. 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 P050A set?
Retry the troubleshooting.
The inspection is complete.