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

MONITOR EXECUTION

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).

Judgement 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.

OBD-II DRIVE CYCLE PATTERN

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. Check the throttle body. (throttle valve area)

Q. Is the throttle valve area dirty?

	Perform cleaning. Refer to Throttle body (throttle valve area) cleaning . Then go to Step 3.

	Go to Step 2.

STEP 2. 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)After the DTC has been deleted, read the DTC again.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is DTC P050B set?

Replace the ECM. When the ECM is replaced, register the ID code. Refer to GROUP 42B, Diagnosis - ID Code Registration Judgment Table <Vehicles with KOS>

or GROUP 42C, Diagnosis - ID Codes Registration Judgment Table <Vehicles with WCM>

. 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 19

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

Q. Is DTC P050B set?

	Retry the troubleshooting.

	The inspection is complete.