P219D Cylinder #2 Imbalance Error
OBD-II Trouble Code Technical Description
Cylinder #2 Imbalance Error
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Toyota, Audi, Kia, VW, Lexus, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
When a code P219D is stored, it means that the powertrain control module (PCM) has detected an imbalance error in the number two cylinder. To monitor the air to fuel ratio for each cylinder of the engine, the PCM uses data input from heated exhaust oxygen sensors (sometimes called air fuel sensors) and the crankshaft position (CKP) and camshaft position (CMP) sensors.
Each oxygen sensor is constructed using a zirconium dioxide sensing element situated in the center of a vented steel housing. Tiny electrodes (usually of platinum) attach the sensing element to wire leads in the oxygen sensor harness connector and the connector plugs into the controller area network (CAN) which connects the oxygen sensor wiring harness to the PCM connector.
Each oxygen sensor is threaded (or studded) into an exhaust pipe. It is situated so the the sensing element is near the center of the pipe. As spent exhaust gases exit the combustion chamber (via the exhaust manifold) and continue through the exhaust system (including catalytic converters), they flow over the oxygen sensors. Exhaust gases enter the oxygen sensor through specially designed vent holes in the steel housing and swirl around the sensing element. Swirling ambient air is drawn through wire lead cavities in the sensor housing in order to fill a tiny chamber in the middle of the sensor. The air (in the tiny chamber) is then heated. This forces the oxygen ions to produce energy that is recognized by the PCM as voltage. Variations between the number of oxygen ions in ambient air (drawn into the O2 sensor), and the number of oxygen molecules in the exhaust, cause the oxygen ions inside the O2 sensor to bounce from one platinum layer to the other, very swiftly and repetitively. As the surging oxygen ions shift between platinum layers, variations in oxygen sensor output voltage occur. The PCM sees these variations in oxygen sensor output voltage as changes in exhaust oxygen concentration. Voltage signal outputs from the oxygen sensors are lower when more oxygen is present in the exhaust (lean condition) and higher when less oxygen is present in the exhaust (rich condition).
Crankshaft and camshaft position sensors are of the electromagnetic variety. They are triggered by a steel ring that rotates with the engine. A signal is sent to the PCM in the form of a waveform pattern. Inconsistencies in the waveform pattern are interpreted by the PCM as variations in engine RPM and/or cylinder efficiency.
If the PCM detects an imbalance in the air to fuel ratio for a engine cylinder two, a code P219D will be stored and a malfunction indicator lamp (MIL) may be illuminated. Most vehicles will require multiple ignition cycles (with a failure) for MIL illumination.
What is the severity of this DTC?
Cylinder imbalance may be caused by either a mechanical or an electrical issue. A code P219D should be categorized as severe and rectified as quickly as possible.
What are some of the symptoms of the code?
Symptoms of a P219D trouble code may include:
Diminished fuel efficiency A lack of general engine performance Stored misfire codes or lean/rich exhaust codes Service engine soon lamp illuminationWhat are some of the common causes of the code?
Causes for this code may include:
Inadequate engine compression Defective oxygen sensor/s Faulty CKP or CMP sensor Burnt, chafed, broken, or disconnected wiring and/or connectors A faultRead: 21
