P050D: Cold Start Rough Idle

GM's direct-injection petrol engines (from about 2016) split the injection into two pulses and retard the ignition after a cold start to heat the catalyst. P050D counts engine cycles with incomplete combustion via the crankshaft misfire detection during this strategy; if the rate reaches the catalyst-damaging misfire threshold, the code sets – once per trip, while the strategy is active (under 45 s running, coolant up to 66 °C). Mostly MIL after two trips, some calibrations without MIL. Ford and FCA do not use P050D.

Symptoms

• Check engine light on (depending on calibration)
• Rough idle or jerking in the first seconds after a cold start
• Usually unremarkable when warm

Most likely causes

• Injector with poor spray pattern or deposits, or injector circuit fault
• Spark plug or ignition coil weak
• Engine module software or calibration
• Poor fuel or low fuel pressure

What to check, in order

Start with the simplest. You can tick off each step.

1. See whether the light is flashing: if so, reduce engine load and avoid driving
2. Inspect the spark plugs, coils, and connectors
3. Swap the coil with another cylinder and see if the misfire moves with it
4. Check the injector and look for air leaks
5. Run a compression test if everything above checks out

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P050D means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 5: Speed and idle
• 0D: Specific fault in that system

Frequently asked questions

Can I keep driving with code P050D?

Avoid driving if the light is flashing or the engine is shaking: unburned gasoline can damage the catalytic converter.

What causes code P050D?

The most common causes are: injector with poor spray pattern or deposits, or injector circuit fault; spark plug or ignition coil weak; engine module software or calibration.

Related codes

• P0300Random/Multiple Cylinder Misfire Detected
• P050ACold Start Idle Control System Performance
• P050BCold Start Ignition Timing Performance
• P02EECylinder 1 Injector Circuit Range/Performance
• P2B95Cold Start Injection Pulse Performance

Sources

• gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
• gsi.ext.gm.com: 19OBDG03D Diagnostics
• static.nhtsa.gov: MC 11011883 0001

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.