Technical Description of OBD-II Trouble Code
O2 Sensor Slow Response – Lean to Rich (Bank 1 Sensor 2)
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 P013B code, it indicates that the powertrain control module (PCM) has detected a slow response time from the downstream oxygen (O2) sensor or circuit for engine bank one, which is the bank of the engine containing the number one cylinder.
Automotive O2 sensors are constructed using a zirconium dioxide sensing element 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 and repetitiously 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). The PCM primarily uses this data 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 P013B code will be stored and a malfunction indicator lamp may illuminate.
Other O2 sensor slow response trouble codes include:
Code Severity & Symptoms
Since a P013B code indicates that an O2 sensor has remained slow for an extended period of time, it should be considered severe.
Symptoms of this code may include:
Causes
Potential causes for this code to be set are:
Diagnostic and Repair Procedures
Some of the main tools required to diagnose a code P013B are a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable vehicle information source (All Data DIY).
Before attempting to diagnose a code P013B, 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 start with a visual inspection of system wiring harnesses and connectors, focusing on those routed near hot exhaust pipes and manifolds, as well as those routed 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 will likely assist you in your 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 P013B code proves to be intermittent, so write it down for later reference. Clear the codes and see if the P013B 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 the data stream display to include only pertinent 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 P013B 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. You may also use it 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 prior to testing system circuit resistance with the DVOM.
Additional diagnostic notes:
