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Summary
  • The diagnostic trouble code (DTC) P050B indicates “Cold Start Ignition Timing Performance.”
  • Your vehicle’s computer sets this code if it detects a malfunction in the ignition timing control system.
  • Common causes of the P050B code are a faulty engine coolant temperature sensor, a severe vacuum leak, and open or shorted circuits or connectors.
  • The symptoms of a P050B code can range from an illuminated check engine light and stalling while idling to a pinging sound during acceleration.

Ignition timing determines when the spark plug fires during the compression stroke. This is measured in relation to the degree of the crankshaft’s position before the piston reaches the top dead center (TDC). If the powertrain control module (PCM) detects a malfunction in the ignition timing control system, the vehicle’s computer will log a P050B code on a scan tool.

What Does the P050B Code Mean?

Diagnostic trouble code P050B stands for “Cold Start Ignition Timing Performance.” This generic powertrain code can apply to modern vehicles with OBD-II.

A “cold start” describes an engine drivability strategy that’s used when the engine is at or below ambient temperature. Ignition timing is slightly advanced when the engine is cold to make up for the lower temperature of the combustion chamber.

car temperature gauge
The code P050B stands for “Cold Start Ignition Timing Performance.” A “cold start” is described as an engine drivability strategy that’s used when the engine is at or below ambient temperature.

The PCM uses 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 will store a P050B if the ignition timing can’t be controlled. This code must be cleared right away to prevent any damage to the engine.

Note: The definition of code P050B might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P050B Code?

What are the Common Symptoms of the P050B Code?

automotive coolant temperature sensor
A faulty engine coolant temperature sensor can result in a registered P050B code.

How to Diagnose the P050B Code

Diagnostic steps can vary depending on your vehicle’s make and model. It’s important to review your vehicle’s repair manual before diagnosing this DTC to avoid costly mistakes.

However, if you aren’t confident in diagnosing your vehicle, you should leave this part to a mechanic. They can find the underlying causes of your DTC and perform the necessary repairs.

How to Fix the P050B Code

Clearing a DTC is no walk in the park. You must find the underlying causes of this code to determine the appropriate fix. Fortunately, there are many OBD-II resources available online that can assist you in diagnosing and fixing your vehicle’s problems. Chilton repair manuals and other similar manuals are helpful, but an ALLDATA subscription is preferable. For DIYers looking for comprehensive factory repair information, ALLDATA offers single-vehicle subscriptions.

Getting a New Coolant Temperature Sensor

Aside from triggering the P050B code, a damaged coolant temperature sensor can wreak all kinds of havoc on the engine. It can activate the check engine light and cause the engine to overheat or idle rough. In some cases, a damaged sensor can even prevent your car from starting. Save yourself from all that trouble by getting a brand-new coolant temperature sensor from CarParts.com today.

As a one-stop shop for the best aftermarket parts, CarParts.com offers a wide selection of high-quality coolant temperature sensors. Easily browse through our catalog using our built-in vehicle selector and search filters. We’re dedicated to making your shopping experience as hassle-free as possible by providing accurate and detailed fitment information for each part. That way, you can take the guesswork out of shopping and get the coolant temperature sensor that best fits your vehicle.

Don’t wait until your engine overheats before replacing your coolant temperature sensor. Check out our catalog of high-quality coolant temperature sensors at CarParts.com and order one today!

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Contact Center Manager and Technical Reviewer at CarParts.com

William “Bill” Guzenski has produced hundreds of how-to videos for the automotive community. He’s an ASE Certified Master Automobile Technician, and is affiliated with the Specialty Equipment Market Association (SEMA). He loves attending race events and car shows throughout the country, as well as traveling in his 40-foot motorhome, exploring abandoned mines and ghost towns.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

File Under : OBD-II Trouble Codes
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