Fix P014D: Mechanic’s solutions that WORKED

The code P014D: O2 Sensor Slow Response – Rich to Lean (Bank 1 Sensor 1) indicates that the oxygen sensor in bank 1, sensor 1 is not switching between rich and lean conditions as quickly as it should. This can affect the engine’s ability to adjust the air-fuel mixture for optimal performance and emissions.

P014D quick overview

Meaning	P014D: O2 Sensor Slow Response – Rich to Lean (Bank 1 Sensor 1)
Is it serious?	Yes, it can lead to poor engine performance, increased fuel consumption, and higher emissions.
Possible causes	– Faulty or contaminated O2 sensor – Exhaust leaks near the O2 sensor – Faulty or outdated Powertrain Control Module (PCM) – Wiring or connector issues related to the O2 sensor – Restricted exhaust or diesel particulate filter (in diesel engines) – Specific driving cycles, like “Package and Delivery”, causing excessive soot
How to diagnose?	Inspect the O2 Sensor: Check for physical damage or contamination. Check for Exhaust Leaks: Especially near the location of the O2 sensor. Scan the PCM: Ensure it has the latest software and consider reflashing if outdated. Examine Wiring and Connectors: Look for damages or disconnections leading to the O2 sensor. Perform a DPF Regen if applicable: Especially for diesel engines showing signs of a clogged particulate filter. Consider Vehicle’s Driving Cycle: Understand the driving conditions the vehicle is mostly subjected to. Test O2 Sensor Response: Use a scan tool or oscilloscope to monitor the O2 sensor’s response time.

How to fix P014D – learn from mechanics

I looked into P014D service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics.I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Ram

Vehicle Information 2012 Ram 3500 SLT 6.7L

Issue + Repair History

• MIL light on with codes P014C and P014D.
• Vehicle was previously serviced 6 weeks ago for the same codes.
• Wiring harness overlay was performed as per TSB 25-002-14.
• B1S1 was replaced.
• EGR valve observed to have a slight leak.
• MAF is functioning correctly, and there are no misfires or intake leaks.

Other OBD2 Codes + Test Results

• P014c: B1S1 slow lean to rich
• P014d: B1S1 slow rich to lean

What Are People Suggesting to Fix the Issue

• Perform an injector balance test.
• Monitor O2 sensors readings and ensure they don’t vary more than 4% from each other.
• Check PCM for the latest software and update if necessary.
• Fix the leaking EGR valve.

What Was the Final Fix Replaced the EGR valve.

Case #2: Nissan

Vehicle Information 2016 Nissan Altima S 2.5L

Issue + Repair History

• MIL light on.
• Vehicle is a fleet vehicle, mostly driven on highways and well-maintained.
• Other Nissan Altimas in the fleet haven’t shown these issues.
• All four current recalls have been addressed.
• PCM updated twice.
• PCV had the updated unit installed.
• Front A/F sensor was replaced under warranty.
• MAF cleaned and replaced.
• Fuel pressure checked.
• Front and rear O2 sensors replaced.
• PCM reflashed at a Nissan dealer.

Other OBD2 Codes + Test Results

• P015b: O2 Sensor Delayed response- Lean to Rich Bank 1 Sensor 1
• P015a: O2 Sensor Delayed response- Rich to Lean Bank 1 Sensor 1
• P014d: O2 Sensor Slow response- Lean To Rich Bank 1 Sensor 1
• P014c: O2 Sensor Slow response- Rich To Lean bank 1 Sensor 1

What Are People Suggesting to Fix the Issue

• Refer to TSB NTB16-117b which calls for various replacements and modifications.
• Return to the dealer for warranty work.
• Check for a PCC valve or vacuum leak causing slow response.
• A/F sensor failures might be due to increased under-hood temperatures caused by cutting the front plastic lower cover.

What Was the Final Fix

• PCV replaced.
• A/F sensor replaced twice.
• Software updated.
• Planning to visit a different dealer with the mentioned TSB for further solutions.

Advice	Diagnostic Step
Check the O2 Sensor	Inspect the O2 sensor for damage, contamination, or malfunction. Replace if necessary.
Inspect for Exhaust Leaks	Examine the exhaust system, especially near the O2 sensor, to ensure there are no leaks affecting readings.
Update or Reflash the PCM	Ensure the Powertrain Control Module (PCM) has the latest software. If not, consider updating or reflashing.
Check Wiring and Connectors	Examine the wiring and connectors leading to the O2 sensor for any signs of damage or disconnection.
Consider Vehicle’s Driving Cycle	Vehicles with specific driving cycles, like “Package and Delivery”, might be more susceptible to this issue.
Perform a DPF Regen if applicable	Use a scan tool to perform a diesel particulate filter regeneration if the vehicle is equipped with one.
Address any Restriction in Exhaust	Ensure there’s no restriction in the exhaust system, which can lead to this code.