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P050B Code: Causes, Symptoms, and How to Repair It! 

  • Engine Codes
  • Gerard Stevens
  • 5 minutes

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Do you notice a significant vacuum leak? Is there a pinging sound coming from your automobile when you accelerate? Then it’s high time you scan your car to know the exact issue. It will probably show that the car activated the P050B code. How serious is this diagnostic trouble code (DTC)? 

The code refers to ‘Cold Start Ignition Timing Performance.’ Since this code is a generic trouble code, it applies to all code having an OBD-II system or to all models manufactured since 1996. It comprises cars from various manufacturers, including but not limited to BMW, Dodge, Ford, Jaguar, Jeep, Land Rover, Mazda, Mitsubishi, and Volkswagen. In addition, of course, there are differences in definitions, diagnosis, and performance from one brand and model to another. 

So, what does the P050B code mean? What are its symptoms? How can you fix it? Here’s more info on this DTC! 

What does the P050B code mean? 

If the car activates this code, it implies that the powertrain control module (PCM) identified a fault with the ignition timing control system. The drivability approach employed by the engine only at or below ambient temperature is called ‘Cold Start.’ 

Among other sensors, the PCM uses the input data from the crankshaft position (CKP) sensor, the camshaft position (CMP) sensor, the engine temperature sensor (ECT), the throttle position sensor (TPS), and the mass airflow (MAF) sensor to calculate the ignition timing strategy. The PCM is programmed to give a base timing strategy and to advance and retard ignition timing as necessary. 

The PCM delays ignition timing to prevent engine damage if the engine overheats or when knock sensors get engaged. A P050B code activates, and a malfunction indicator lamp (MIL) may illuminate if the PCM cannot control ignition timing.  

Related codes: P050A, P050C, P050D, and P050E.  

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How serious is the P050B code?  

Poor engine performance, damaged catalytic converters, and decreased fuel efficiency can all be consequences of incorrect ignition timing. So, you should treat engine error code P050B seriously, diagnose it, and do the fixes at the earliest.  

Can I drive with the P050B code?  

It is better not to drive your car after the code appears. Incorrect timing may lead to poor engine performance, damage to the catalytic converter, and lower fuel efficiency. So, visit a skilled mechanic as soon as the code appears and rectify the issue at the earliest.  

What causes a P050B code? 

These are some factors that cause the code to activate. 

  • A damaged ECT sensor.  
  • CKP or CMP sensors become faulty. 
  • High vacuum leakage. 
  • The circuits and connectors get short. 

What are the symptoms of the P050B code?  


These are typical symptoms you can observe when the P050B code activates. 

  • Extremely rich exhaust.  
  • The engine stalls at idle. 
  • There will be a pinging noise from your car when you accelerate. 
  • Presence of codes related to CKP or CMP sensors. 

How to diagnose P050B code 

Follow these steps thoroughly while diagnosing the DTC. 

  • You must have access to a trustworthy source of information for troubleshooting the P050B code, such as a diagnostic scanner with an integrated oscilloscope and a digital voltmeter/ohmmeter (DVOM).  
  • You need diagnostic flowcharts, wiring diagrams, connection face views, connector pinout charts, testing procedures, and component specifications to correctly diagnose the P050B code. Your car’s service manual will have all this info.  
  • The next step is visually verifying the parts, including the wiring joints, wiring lines, and all other associated connectors.  
  • Check for oil contamination in the CKP or CMP sensor connectors. You must initiate a professional cleaning or replacement of the sensors and connectors if needed. 
  • Put the oscilloscope in place and attempt to start the cold engine. Ensure that the scope test leads point away from the moving components. 

Common mistakes made while diagnosing the code  

  • Check the sensor’s signal circuit using the oscilloscope’s positive test lead. 
  • The sensor’s negative test lead must connect to the appropriate ground wire. 
  • Choose the appropriate voltage settings on the scope as the reference voltage for the CKP and CMP sensors is typically 5 volts. 
  • Turn on the engine and observe the waveform pattern on the scope’s display. 
  • The waveform pattern must be uniform at every RPM level with no voltage peaks or jitters. Inconsistent waveforms may indicate a malfunctioning sensor or a very poor electrical connection. 

How do I fix code P050B? 

These are the various steps you can follow to repair the code. 

  • Do a fix for the vacuum leakage.  
  • Get a replacement for the ECT sensor. 
  • Change the faulty circuits or connectors. 
  • Replace the Throttle Position Sensor. 
  • Doing a replacement for the damaged CMP sensor with a new one.  

The bottom line 

  • The code means that PCM identified a fault with the ignition timing control system.  
  • The code can lead to poor engine performance, decreased fuel efficiency, and a faulty catalytic converter.  
  • Visit a skilled mechanic to rectify the issue as soon the code appears.  

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