This Preliminary Information communication provides information to the technician for a vehicle setting both a P2635 and P018B diagnostic trouble codes. The following steps may help to determine if this is caused by a fuel pressure sensor not reading the low end of the pressure range. Â Technician is to make sure the engine is cold and install the Multiple Diagnostic Interface along with Global Diagnostic System 2. Â Navigate to fuel system depressurize and at engine idle depressurize the fuel system. The fuel pressure sensor value should drop to 0 and the engine will stall. Â If a sensor is causing this concern the suspected sensor will not drop to 0 the engine will stall however the sensor will still read 30 to 40 pounds per square inch.Â