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DTC P050B: Ignition Timing Retard Insufficient
 
 
 
 
TECHNICAL DESCRIPTION
  • After starting the engine in the cold state, the ECM retards the ignition timing to early activate the catalyst by letting out the high temperature exhaust gases.
  • The ECM monitors whether the retard ignition timing control is normal or not.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • After starting the engine in the cold state, the retard ignition timing control is abnormal, which is caused by a decrease in idle speed and so on.
 
 
MONITOR EXECUTION
  • Once per driving cycle
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
DTC SET CONDITIONS
Logic Flow Chart
 
 
Check Conditions
  • Under the ignition timing retard control.
  • Engine coolant temperature is between 7°C (45°F) and 41°C (106°F).
Judgment Criteria
  • For 10 seconds, the difference between the basic ignition timing and the target/specified ignition timing is 3°CA or less on average during the retard control.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • None
 
 
OBD-II DRIVE CYCLE PATTERN
  • Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 .
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be stored are: )
  • Dirtiness around throttle valve.
  • 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. 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 3.
Repair it. Then go to Step 2.
 
STEP 2. 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) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC P050B stored?
Replace the ECM (Refer to Removal and Installation ). Then go to Step 3.
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
 
STEP 3. Test the OBD-II drive cycle.
(1) Carry out test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P050B stored?
Retry the troubleshooting.
The inspection is complete.