Fuel System Codes

Fuel Pump Secondary Circuit Low

The fuel pump feedback circuit voltage is lower than expected, indicating the pump is not running at proper voltage.

Fuel System Leak Detected — Large Leak

The ECM has detected a large fuel system leak based on a significant, rapid drop in fuel rail pressure that cannot be explained by normal injector demand.

Fuel Rail/System Pressure Too High

Fuel pressure is higher than commanded, which can cause rich running and injector damage.

Fuel Pressure Regulator Circuit Open

Open circuit in the fuel pressure regulator control circuit.

Fuel Pressure Regulator Circuit Low

Fuel pressure regulator control circuit voltage is too low.

Fuel Rail Pressure Sensor Circuit

Fault in the fuel rail pressure sensor circuit. This sensor is critical for direct injection and common rail diesel systems to control fuel pressure precisely.

Fuel Rail Pressure Sensor Range/Performance

The fuel rail pressure sensor reading does not match expected values for current operating conditions.

Fuel Rail Pressure Sensor Circuit Low

The fuel rail pressure sensor is sending a signal below minimum expected value.

Fuel Rail Pressure Sensor Circuit High

The fuel rail pressure sensor signal is above maximum expected value.

Fuel Pump Secondary Circuit High

The fuel pump feedback circuit shows higher than expected voltage.

Fuel Pressure Regulator Circuit High

Fuel pressure regulator control circuit voltage is too high.

Fuel Rail/System Pressure Too Low

The fuel pressure in the fuel rail is lower than commanded. This causes a lean condition and can lead to engine damage.

Fuel Pressure Regulator Performance

The fuel pressure regulator is not maintaining correct pressure.

Injector Circuit Malfunction Cylinder 1

Fault in the fuel injector circuit for cylinder 1. The injector is not receiving proper electrical control signal.

Injector Circuit Malfunction Cylinder 2

Fuel injector circuit fault on cylinder 2.

Fuel Injector Circuit Malfunction

General fault in the fuel injector circuit. The ECU cannot properly control one or more fuel injectors.

Injector Circuit Malfunction Cylinder 3

Fuel injector circuit fault on cylinder 3.

Injector Circuit Malfunction Cylinder 4

Fuel injector circuit fault on cylinder 4.

Injector Circuit Malfunction Cylinder 5

Fuel injector circuit fault on cylinder 5.

Injector Circuit Malfunction Cylinder 6

Fuel injector circuit fault on cylinder 6.

Injector Circuit Malfunction Cylinder 7

Fuel injector circuit fault on cylinder 7.

Injector Circuit Malfunction Cylinder 8

Fuel injector circuit fault on cylinder 8.

Fuel Pump Primary Circuit

Fault in the fuel pump primary circuit. The ECU cannot properly control the fuel pump.

Fuel Composition Sensor Circuit Malfunction

The fuel composition sensor, used on flex-fuel vehicles to detect ethanol content, has a circuit fault.

Cylinder 1 Injector Circuit High

The fuel injector circuit for cylinder 1 is reading a higher resistance/voltage than expected.

System Too Rich Bank 1

Bank 1 is running too rich. The ECM is removing fuel but cannot get lean enough.

System Too Lean Bank 2

Bank 2 is running lean. On V6/V8 engines this often indicates a vacuum leak on the Bank 2 side of the intake.

System Too Rich Bank 2

Bank 2 is running excessively rich.

Fuel Trim Malfunction Bank 1

The fuel trim (fuel correction) on Bank 1 is outside acceptable limits.

Fuel Trim Malfunction Bank 2

Fuel trim on Bank 2 is out of range.

Fuel Temperature Sensor A Circuit

The fuel temperature sensor circuit has a fault. This sensor monitors fuel temperature to adjust injection timing and quantity for optimal combustion.

Fuel Temperature Sensor A Range/Performance

The fuel temperature sensor reading is outside the expected range for current conditions.

Fuel Temperature Sensor A Circuit Low

The fuel temperature sensor signal is lower than the minimum expected value.

Fuel Temperature Sensor A Circuit High

The fuel temperature sensor signal is higher than maximum expected value.

Cylinder 1 Injector Circuit Low

The fuel injector circuit for cylinder 1 is reading a lower resistance/voltage than expected.

System Too Lean Bank 1

The engine is running too lean on Bank 1. The ECM is adding fuel to compensate but cannot get rich enough.