P2309 Ignition Coil D Primary Control Circuit Low
OBD-II Trouble Code Technical Description
Ignition Coil D Primary Control Circuit Low
What does P2309 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 Mercedes, Ford, Mini, GMC, Sprinter, Chevrolet, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
If your vehicle has stored a code P2309, accompanied by a malfunction indicator lamp (MIL), it means that the powertrain control module (PCM) has detected an unexpectedly low voltage condition in the primary control circuit of the ignition coil designated with the letter D. Refer to a manufacturer specific guide to determine which is the "D" circuit for your particular application.
Primary circuits of the ignition coil are the wires which supply battery voltage to the coil. Voltage is delivered through fuses, relays, and various other sources. The high-energy ignition boot, spark plug boot, or spark plug wire is NOT considered a primary circuit.
Typically, the ignition coil is supplied with battery voltage and ground. When the ground signal is interrupted (momentarily), the ignition coil emits a high voltage spark which also fires the spark plug. Spark plug operation is a necessary component in the internal combustion engine. If primary voltage to the ignition coil is insufficient, high-energy voltage emission will not occur and the engine cylinder will not produce horsepower.
Typical individual cylinder (coil-on-plug COP) ignition coils:
What is the severity of this DTC?
When a P2309 is stored, the cause should be diagnosed as soon as possible. Symptoms which likely accompany these codes will usually demand immediate attention.
What are some of the symptoms of the code?
Symptoms of a P2309 trouble code may include:
Engine misfire Diminished engine performance Reduced fuel efficiency Other related codes Fuel injector operation for the affected cylinder may be disabled by the PCMWhat are some of the common causes of the code?
Causes for this code may include:
Bad relay or blown fuse (fusible link) PCM failure Open or shorted wiring or wiring connectors (wildlife damage) Defective ignition coil Faulty camshaft or crankshaft sensor or wiringWhat are some P2309 troubleshooting steps?
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 P2309.
You may save yourself time and trouble 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.
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 P2309 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 conn
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