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P050D Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P050d is an OBD-II Code that refers to Cold Start Rough Idle


A P050d code is caused by an ECM (Engine Control Module) receiving a signal from the PCM that the engine started and is running extremely rough at idle. The PCM monitors the crankshaft position sensor input for a certain number of revolutions before it tells the ECM that the engine has started. If the engine does not reach this minimum threshold, then P050D will set.


Common causes for this code include:

  • Shorted or open circuits, contacts, or connections
  • Low fuel pressure or volume
  • Vacuum or air leaks
  • ECT sensor error
  • Ignition coils, spark plugs, or plug boots may be faulty


The symptoms of a P050D code are:

  • Lean Code
  • Rough Idle
  • Hard Start
  • Lack of Power
  • Hesitation or Stalling
  • Poor Performance and Fuel Economy
  • If the vehicle has a manual transmission, it will not shift properly. If the vehicle is an automatic, then slippage may be present. The engine may idle very roughly at times too. You can have other


To diagnose a P050d DTC code, a technician would:

  1. Scan for codes and check the freeze frame data
  2. Inspect for vacuum leaks using a smoke machine
  3. Inspect ignition components such as coils, plug boots, and spark plugs 
  4. Inspect ECT sensor connections for poor electrical connections 
  5. Perform a fuel pressure test to ensure proper pressure is being supplied to the engine. 
  6. If it is low, check the fuel pump and filter. They may be clogged with contaminants or damaged internally requiring replacement of these parts. 
  7. Also make sure there are no open circuits in the wiring harness related to the fuel system.
  8. Clear code and test drive vehicle

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P050D code:

  • Not checking for a battery drain
  • Misdiagnosing the PCM as the ECM
  • Resetting systems and not clearing codes from all modules before driving
  • Failure to start with a known good spark plug wire, distributor cap, rotor, and ignition coil
  • Not replacing parts that have been verified as defective by a state of tune or equivalent

How serious is this?

A P050D code can cause major issues that can lead to expensive repairs, so it is important that the code be diagnosed and fixed as soon as possible.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Repair vacuum leaks
  • Replace faulty spark plugs, ignition coils, or plug boots
  • Fix shorted or open circuits or connectors
  • Check for fuel in the tank
  • Switch ECT sensor

Related codes

A P050D is related to and may be accompanied by the following codes:

P050B – Cold Start Injector 1 Performance

P050C – Cold Start Injector 2 Performance

P051A – Warm-Up Regulator Performance

P052A – Engine Oil Temperature Sensor Circuit Low Voltage


In conclusion, the P050d code is a generic trouble code that means the computer has detected an issue with the Cold Start Rough Idle system on your engine. This code can be caused by several different problems. However, these are all fairly simple issues that can be fixed relatively quickly and easily. If you have this code, check around the engine first to see if you notice any commonalities between the problem(s) that caused it. You may find a vacuum hose or wire off or just need to replace some worn spark plugs, etc., which will cause the P050D code go away for good.