Diagnostic Instructions
DTC Descriptors
DTC P050D: Cold Start Rough Idle
Circuit Description
This diagnostic is performed when converter light off is enabled or when the converter light off is disabled due to idle instability. Converter light off refers to the transition of the converter from a cold start condition to the state when the converter
has warmed up enough to begin catalytic conversion (Closed Loop). In order to help the converter heat up as quickly as possible and reduce emissions, the spark retard is modified under cold start conditions. This diagnostic monitors the enable and disable conditions
of converter light off spark retard. The fail/pass determination is based on the monitoring for multiple key cycles and fueling cycles.
Conditions for Running the DTC
• | DTCs P0106, P0107, and P0108 are not set. |
• | The engine has been running between 5-150 seconds. |
• | The engine coolant temperature (ECT) is between -5 to +45°C (+23 to +113°F). |
• | The fuel level is greater than 5 percent. |
• | The barometric pressure (BARO) is greater than 72 kPa. |
• | The calculated valve train temperature is less than 333°C (631°F). |
• | The converter Light-off spark conditions are met. |
• | The vehicle has been refueled at least once after the DTC set. |
• | This DTC runs once per ignition cycle once the above conditions are met. |
Conditions for Setting the DTC
The ECM detects Converter Light-off spark retard is disabled due to idle instability.
Action Taken When the DTC Sets
DTC P050D is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P050D is a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine running, observe the DTC information with a scan tool. DTC P050D should not set.
⇒ | If DTC P050D is set, Inspect for the following conditions: |
• | Vacuum leaks at the intake manifold, throttle body, and injector O-rings. |
• | Leaking crankcase ventilation system. |
• | Splits, kinks, or improper connections at the vacuum hoses |
• | The air intake duct for being collapsed or restricted possibly by a restricted air filter. |
- If all conditions test normal, test the engine for a mechanical condition. Refer to
Symptoms - Engine Mechanical.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.