P3102 - FAULT CODE - OBD2

P3102 BMW, MINI: CYLINDER 1 HIGH-PRESSURE FUEL INJECTOR LOW SIDE CIRCUIT HIGH

The injection valve is controlled by a solenoid, which provides a spray into the combustion chamber at high pressure. This valve is a retractable plunger type that has a high level of flexibility in its spray spread pattern, i.e. in angle and shape. The discharge orifices form a high-precision injection pattern so that the distribution can be uniform.

The retractable plunger solenoid controls the injection valve continuously, maintaining stable propagation properties, including temperature and pressure levels located inside the combustion chamber. The fuel is injected into the chamber at a pressure between 50 and 200 bar during the intake and compression strokes.

On the other hand, in the warm-up phase, a small amount of fuel is injected so that the catalytic converter can reach its effective operating temperature. During cold starts, the fuel is sprayed into the compression stroke in multiple pulses.

If this strategy is applied, reliable cold starts are guaranteed along with substantial improvements in some parts of pollutant emissions and fuel consumption.

The DME (Digital Motor Electronics) has a diagnostic that monitors the activity of the low voltage side of the fuel injector. If after this monitoring a short circuit on B+ is detected on the injector of cylinder 1, the DTC P3102 OBDII code will be set.

• The Check Engine light turns on.
• The engine has trouble starting.
• Limited acceleration.

The P3102 OBD2 fault code is set for one of the following reasons:

• Fuel injector 1 wiring may be in poor condition.
• Poor electrical connections in the fuel injector 1 circuit may be causing the short circuit.
• Fuel injector 1 may be faulty.
• The DME may be defective.

To troubleshoot the P3102 OBDII diagnostic code, try this:

• First, consult the Service Bulletins.
• Check all the wiring and connectors that relate to the fuel injector for cylinder 1. Check these components for common damage, such as wear or corrosion. If such conditions are found, make corrections.
• Measure injector 1 circuit voltages to locate the short or condition that is causing the high voltage. All of these electrical values should match the manufacturer's specifications, otherwise, make repairs.
• Follow the recommendations given by the manufacturer to carry out such a diagnosis. Correct if necessary.