P214D – Long Term Fuel Trim (LTFT) Bank 1 Range/Performance Problem

Stephen Darby

By Stephen Darby (Contact Me)
Last Updated 2019-11-26
ASE Master Tech

Trouble CodeFault LocationProbable Cause
P214D Long term fuel trim (LTFT), bank 1 -range/performance problem Catalytic converter, exhaust leak, injector leakage, H02S

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What Does Code P214D Mean?

If your vehicle has stored a code P214D, it means that the powertrain control module (PCM) has detected a malfunction in the long term fuel trim (LTFT) system for bank one. Bank 1 specifies the bank of the engine which contains the number one cylinder.

Codes which involve fuel trim can be confusing because of the terminology used. Since the word “trim” is typically used to describe cutting something off or taking something away, it is easy to see how things get twisted. You see, fuel trim may decrease fuel to lean the fuel mixture or increase fuel to richen the fuel mixture. When observing fuel trim in the scanner data stream, it appears in negative and positive parameters. Zero fuel trim would (theoretically) be a perfect LTFT. If your engine is running excessively rich (too much fuel) over an extended period of time, you might see a LTFT of -1.49%. Likewise, an excessively lean (not enough fuel) condition might yield a LTFT reading of +1.49%.

 

 

Short term fuel trim (STFT) is configured in much the same manner.

Although STFT also has maximum and minimum parameters, it changes much more rapidly and is given much more room for fluctuation than LTFT. The PCM actually uses STFT to configure LTFT. If LTFT for engine bank one exceeds the maximum allowable parameter, in either direction, a code P214D will be stored and a malfunction indicator lamp (MIL) may be illuminated. Multiple failures will typically be required for MIL illumination.

What are the common causes of code P214D?

  • Clogged fuel filter
  • Bad fuel pump
  • Faulty fuel pressure regulator
  • Fuel leak
  • Manifold air pressure or mass airflow sensor failure
  • Oxygen sensor failure
  • Engine vacuum leak

What are the symptoms of code P214D?

  • Diminished engine performance
  • Decreased fuel efficiency
  • Black smoke from exhaust
  • Hesitation, sag or stumble when accelerating

How do you troubleshoot code P214D?

You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of reliable vehicle information in order to accurately diagnose a code P214D.

You may save yourself time by searching for technical service bulletins (TSB) that replicate the code stored, vehicle (year, make, model, and engine), and symptoms exhibited. This information may be found in your vehicle information source. If you find the right TSB, it could yield a speedy solution to your diagnosis.

Diagnose and repair any fuel delivery related codes before attempting to diagnose the P214D. Make sure that fuel pressure and volume are within specifications and make sure that the fuel is in good condition before proceeding. Also make sure that no vacuum leaks are present. LTFT reacts to excessive changes in fuel mixture. Fix the fuel mixture and ninety-nine percent of the time, you’ll fix the fuel trim problem.

 

 

After you connect the scanner to the vehicle diagnostic port and retrieve all stored codes and pertinent freeze frame data write the information down (in case the code proves to be an intermittent one). After that, clear the codes and test drive the vehicle until one of two things happens; the code is restored or the PCM enters readiness mode.

The code may be more difficult to diagnose if the PCM enters readiness mode at this point, because the code is intermittent. The condition which caused the P214D to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, continue with the diagnosis.

You may obtain connector face views, connector pinout charts, component locator charts, wiring diagrams, and diagnostic flow charts (pertaining to the code and vehicle in question) using your source of vehicle information.

Perform a visual inspection of related wiring and connectors. Repair or replace wiring that has been cut, burned, or damaged.

Use the DVOM to test voltage and ground circuits at the PCM. If no voltage is detected, check system fuses. Replace blown or otherwise defective fuses as required and retest.

If voltage and ground are detected at the PCM, test the corresponding circuits at the oxygen sensors, mass airflow sensor and manifold air pressure sensor. If no voltage is detected there, suspect an open circuit between the component in question and the PCM.

Codes Related to P214D

  • P2187 System Too Lean at Idle Bank 1
  • P2188 System Too Rich at Idle Bank 1
  • P2191 System Too Lean at Higher Load Bank 1
  • P2192 System Too Rich at Higher Load Bank 1
  • P0170 Fuel Trim Malfunction Bank 1
  • P0171 System too Lean Bank 1
  • P0172 System too Rich Bank 1

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