P050B Cold start ignition timing performance: the engine is not reaching the expected spark timing during the cold-start warm-up

Cold start ignition timing performance

Monitor

KBB says you may drive with the code but it is not advisable, since drivability and the catalytic converter could be affected.

It gets more serious if:

  • Inspect soon: Get it inspected soon if the engine stalls at idle, misfires or pings, since KBB lists those with this code.

Source: how we rate severity

P050B in short

P050B means the computer sees poor ignition timing control during a cold start. A faulty coolant sensor, vacuum leak, clogged air filter, crank or cam sensor fault or low battery voltage can cause it. Chrysler and Land Rover bulletins say software or calibration was the cause on some models.

During a cold start the computer holds the spark timing late to warm the catalytic converter quickly. P050B sets when the timing does not follow that plan within limits.

KBB lists a faulty coolant temperature sensor, a severe vacuum leak, a clogged air filter, crank or cam sensor faults, electrical connections and battery voltage. Symptoms include stalling at idle, pinging and poorer economy.

Chrysler bulletin 18-002-13 covers the 2013 Dart with a computer software flash, and Land Rover says an OBD calibration error set P050B-92 and -93 on the 2014-2015 Evoque with no hardware fault found. A Land Rover LR2 owner reports the dealer doing an ECM update for P050B.

Most likely causes

  1. Faulty coolant temperature sensor

    Common general cause
    Why it ranks here
    KBB lists a faulty engine coolant temperature sensor first.
    What would change this
    Rises if the sensor reading is off against real temperature. Falls if it tracks correctly.
    How to test the engine coolant temperature (ect) sensor

  2. Vacuum leak or clogged air filter

    Common general cause
    Why it ranks here
    KBB lists a severe vacuum leak and a clogged air filter; Chrysler's Dart bulletin sets P050B with a high airflow/vacuum leak code P2173.
    What would change this
    Rises if other airflow or lean codes are stored. Falls if the intake system is sealed and clean.
    How to test the vacuum hoses and intake leaks

  3. Crankshaft or camshaft position sensor fault, or poor electrical connections

    Possible — needs testing
    Why it ranks here
    KBB lists defective crank or cam position sensors, electrical connection faults and battery voltage.
    What would change this
    Rises if crank or cam codes are stored too. Falls if those sensors are normal.

  4. Software or calibration error (Dart, Compass, Patriot, Evoque)

    Supported by vehicle data
    Why it ranks here
    Chrysler 18-002-13 Rev A is a software flash on the 2013 Dart and FCA 1807014 covers cold start improvements with P050B on 2015 Compass and Patriot; Land Rover LTB00799NAS1 names an OBD calibration error on the Evoque; an LR2 owner reports an ECM update.
    What would change this
    Rises on a listed vehicle with no hardware fault found. Falls if a hardware cause is confirmed.
    How to test the engine control module (ecm / pcm)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read all stored codes and freeze-frame data and note other codes stored with P050B.

    Low riskTool: OBD-II scan tool

    • IfAirflow, vacuum or lean codes are stored too

      It meansCheck for a vacuum leak.

      Go to step 2

    • IfCoolant or crank/cam sensor codes are stored too

      It meansTest those sensors.

      Go to step 2

    • IfOnly P050B is stored on a listed vehicle

      It meansAsk about the software bulletin.

      Go to step 3

  2. Inspect the air filter and intake hoses for leaks, compare the scan tool coolant temperature with real temperature on a cold engine, and have the battery tested.

    Low riskTool: scan tool, flashlight, battery tester

  3. Ask a dealer whether a software or calibration update applies to your VIN.

    Best left to a shop

    Warning:This needs specialist tools and vehicle service information. Leave it to a shop.

Symptoms

  • Check engine light on
  • Stalling at idle Gets more serious: stop and have it checked.
  • Pinging or misfire Gets more serious: stop and have it checked.
  • Poor fuel economy

How to fix

  1. Check that the air filter is clean.

  2. Have the battery tested.

Parts and cost context

  • Engine coolant temperature (ECT) sensor:The sensor is cheap but only replace it if its reading is wrong. Get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Dodge

  • 2013 · Dart

    Supported by vehicle data

    Chrysler 18-002-13 Rev A names P050B as cold start ignition timing performance and gives a software flash. Whether the bulletin is still current is not verified.

  • 18-002-13 Rev AStatus unverified

    MIL with P000B, P050B and P2173

    2013dart · NHTSA 10189381

    The repair is a computer software flash with drivability and transmission enhancements.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Land Rover

  • 2014–2015 · Range Rover Evoque

    Supported by vehicle data

    Land Rover LTB00799NAS1 attributes P050B-92 and -93 to an OBD calibration error. Whether the bulletin is still current is not verified.

  • LTB00799NAS1Status unverified

    MIL with P050B-92, P050B-93 and misfire codes

    2014–2015range-rover-evoque · NHTSA 10105739

    No hardware fault is found; the cause is stated as an OBD calibration error.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Jeep

  • 2015 · Compass

    Supported by vehicle data

    FCA 1807014 lists P050B with P219A under cold start improvements. Whether the bulletin is still current is not verified.

  • 1807014Status unverified

    MIL, P219A, P050B and cold start improvements

    2015compass, patriot · NHTSA 10232007

    The NHTSA flat file gives the title only.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P2173The engine computer has seen more airflow into the engine that the throttle position can't account for, which usually means air is leaking in somewhere

    Shares causes Supported by vehicle data

    Chrysler bulletin 18-002-13 lists P050B with P2173 (high airflow or vacuum leak) on the 2013 Dart.

  • P000BExhaust camshaft slow to respond to the computer (bank 1)

    Shares causes Supported by vehicle data

    Chrysler bulletin 18-002-13 lists P050B with P000B on the 2013 Dart.

  • P219AThe engine computer has detected that the cylinders on bank 1 are running at noticeably different air-fuel ratios from each other

    Shares causes Supported by vehicle data

    FCA bulletin 1807014 lists P219A with P050B on 2015 Compass and Patriot.

All Ignition and engine position sensors codes

P050B questions

Is P050B a hardware problem?

Not always. Chrysler and Land Rover bulletins say software or calibration set it on some models, so check for updates after the basic tests.

Sources and review

  1. P050B code page (OBD-II codes) — Kelley Blue Book
  2. Chrysler bulletin 18-002-13 Rev A (NHTSA 10189381): 2013 Dart MIL with P000B, P050B and P2173 — Chrysler Group
  3. FCA bulletin 1807014 (NHTSA 10232007): 2015 Compass and Patriot MIL with P219A and P050B — Chrysler Group
  4. Land Rover LTB00799NAS1 (NHTSA 10105739): 2014-2015 Evoque MIL with P050B-92, P050B-93 and misfire codes — Jaguar Land Rover
  5. NHTSA complaint ODI 10579733: Land Rover LR2 2008, dealer read P050B and did an ECM update — NHTSA Office of Defects Investigation
Last reviewed
Written by
Saurabh K.
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