DTC Advanced Diagnostics: P050B
DTC P050B:Cold Start Ignition Timing Control System Performance Problem

General Description



The quick warm system increases air flow and retards ignition timing to accelerate the warm-up of the catalyst on cold engine start. If the ignition timing is excessively advanced, the powertrain control module (PCM) detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration*1
6.0 seconds or more
Duration*2
5.0 seconds or more
DTC Type
Two drive cycles, MIL on
*1: CVT
*2: M/T

Enable Conditions
Condition
Minimum
Maximum
Duration of quick warm-up system operation after engine start-up
–
40 seconds
Engine coolant temperature [ECT SENSOR 1]
50 °F (10 °C)
122 °F (50 °C)
Fuel feedback
Closed loop
Throttle valve
Fully closed
Accelerator pedal position
Released
Other
Vehicle stopped
[ ]: HDS Parameter

Malfunction Threshold
The ignition timing is excessively advanced.

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
Intake air duct breakage
Intake air duct misinstalled
Air cleaner breakage
Air cleaner damage
Air cleaner clogged
Throttle body clogged
Intake air system clogged
Mass airflow (MAF) sensor failure
Intake air temperature (IAT) sensor failure
Engine coolant temperature (ECT) sensor 1 failure
Air fuel ratio too rich
Air fuel ratio too lean
Ignition system failure

Confirmation Procedure
Operating Condition
1.
Leave the vehicle until the engine coolant temperature [ECT SENSOR 1] lowers to 122 °F (50 °C) or less.
2.
Start the engine, and let it idle for at least 6 seconds*1 (5 seconds)*2.

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.