P015D O2 Sensor Delayed Response – Lean to Rich (Bank 2 Sensor 1)

Technical Description of OBD-II Trouble Code

O2 Sensor Delayed Response – Lean to Rich (Bank 2 Sensor 1)

What does that signify?

This diagnostic trouble code (DTC) is a generic powertrain code, which means it is applicable to OBD-II equipped vehicles (GMC, Chevrolet, Ford, Dodge, Chrysler, VW, Toyota, Honda, etc.). Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.

When an OBD-II equipped vehicle has a stored P015D code, it indicates that the powertrain control module (PCM) has detected a delayed response time from the upstream oxygen (O2) sensor or circuit for engine bank two. Bank 2 refers to the bank of the engine that does not contain the #1 cylinder.

Automotive O2 sensors are constructed using a zirconium dioxide sensing element that is protected by a specially designed, vented, steel housing. Platinum electrodes are used to attach the sensing element to wire leads in the O2 sensor wiring harness, which is connected to the PCM through the controller area network (CAN). The PCM receives an electrical signal based on the percentage of oxygen particles in the engine exhaust compared to the oxygen content of ambient air.

Exhaust gases flow over/through the upstream O2 sensor in the exhaust manifold(s) and down pipe(s). The exhaust flows through the O2 sensor vent holes in the steel housing and across the sensing element, while ambient air is drawn through the wire lead cavities and trapped in a small chamber in the center of the sensor. The exhaust heats the trapped ambient air, causing the oxygen ions to produce voltage.

Deviations between the concentration of oxygen molecules in the ambient air drawn into the center cavity of the O2 sensor and the concentration of oxygen ions in the spent exhaust gases cause the heated oxygen ions inside the O2 sensor to rapidly jump between platinum layers. These voltage fluctuations are identified by the PCM as changes in exhaust oxygen concentration, indicating whether the engine is running lean (too little fuel) or rich (too much fuel). This data is primarily used by the PCM to calculate fuel delivery and ignition timing strategy, as well as to monitor catalytic converter efficiency.

If the O2 sensor fails to cycle as rapidly and regularly as expected over a set period of time and under certain predetermined circumstances, a P015D code will be stored and a malfunction indicator lamp may illuminate.

Other oxygen sensor delayed response trouble codes include:

Code Severity & Symptoms

Since a P015D code indicates that an O2 sensor has remained slow or unresponsive for an extended period of time, it should be considered severe.

Symptoms of this code may include:

Causes

Possible causes for this code to be set are:

Diagnostic and Repair Procedures

Some of the main tools required to diagnose a code P015D are a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable vehicle information source (All Data DIY).

Before attempting to diagnose a code P015D, all engine misfire codes, throttle position sensor codes, manifold air pressure codes, and mass air flow sensor codes must be diagnosed and repaired. An engine that is not running efficiently can cause various codes to be stored.

Professional technicians typically begin with a visual inspection of system wiring harnesses and connectors, paying attention to harnesses that are near hot exhaust pipes and manifolds, as well as those near sharp edges like those found on exhaust shields.

Search for technical service bulletins (TSB) in your vehicle information source. If you find one that matches the symptoms and code/s presented by the vehicle in question, it can greatly assist in the diagnosis. TSB listings are compiled from thousands of successful repairs.

Next, connect the scanner to the vehicle diagnostic port and retrieve all stored trouble codes and freeze frame data. This information may be helpful if the P015D code proves to be intermittent, so it is advisable to write it down for future reference. Clear the codes and see if the P015D is reset.

If the code is reset, start the engine, allow it to reach normal operating temperature, and then let it idle (with the transmission in neutral or park). Use the scanner data stream to observe O2 sensor input data.

Narrow down the data stream display to include only relevant data for a faster and more accurate data response. If the engine is running efficiently, upstream O2 sensor data should fluctuate regularly between 1-millivolt (.100-volts) and 9-millivolts (.900-olts). If voltage fluctuations are slower than expected, a P015D code will be stored.

You can connect the DVOM test leads to the sensor ground and signal wires to monitor live data from the O2 sensor. The DVOM can also be used to check the resistance of the O2 sensor in question, as well as voltage and ground signals. To prevent control module damage, disconnect related controllers before testing system circuit resistance with the DVOM.

Additional diagnostic notes:

Professional Service

While we always recommend resolving this issue mechanically, if for some reason that is not possible, we offer the option to permanently delete this specific DTC. All other codes will continue to function. If you are interested in this option, please upload your ECU file to our portal.