How does a mechanic diagnose the P0193 code?
The mechanic will start by inspecting the wiring and connectors for melted wires, broken wires, and corrosion. Repairing the wiring and connections if necessary.
They will use an OBD-II scanner to retrieve freeze frame data and trouble codes stored by the power control module.
They will complete a test drive, after clearing the codes, to see if the P0193 trouble code returns.
If the trouble code P0193 does not return immediately, this indicates the possibility of an intermittent issue. Intermittent problems may need to get worse before a proper diagnosis can be made.
If the car will not start, there is a possibility that there is no fuel in the fuel tank. Use a fuel pressure gauge to test the fuel pressure. Low fuel pressure is an indication that the car has little to no fuel.
To make sure the fuel pump is operating properly, the mechanic will listen to it. If the car won’t start, but they can still hear the fuel pump, the fuel injector circuitry could be faulty or a fuel filter could be clogged.
If the car won’t start and they cannot hear the fuel pump, they will try starting the car while another person taps on the bottom of the fuel tank. If the car starts, this means that the fuel pump needs to be replaced.
If the car does not start, they will check the battery voltage at the fuel pump connector. If there is no battery voltage at the fuel pump connector, they will check the fuse circuit, fuel pump relay circuit, and power control module circuit for any faults.
If these components are operational, inspect the fuel rail pressure sensor. Test the reference voltage of the fuel rail pressure sensor, using a digital volt ohmmeter, while the car is running. The voltage reading should be 5-volts. If this test is successful, test the ground wire.
If there is both a reference signal and ground signal, test the sensor resistance. If the sensor resistance test results do not meet the manufacturer’s specifications, the fuel rail pressure sensor will need to be replaced.
If the circuitry and sensors are working properly, there is a chance that the power control module is faulty. This is rare, but would require replacement and reprogramming.
Sent from my iPad using Tapatalk