Test Description

The numbers below refer to the step numbers in the diagnostic procedure.

1. 1
   
   The DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS, prompts technician to complete some basic checks and to store "Freeze Frame" data on scan tool if applicable. This creates an electronic copy of data taken when fault occurred. Information is then stored in scan tool for later reference.
2. 3
   
   This step checks to see if fuel system pressure is within specifications with ignition on and fuel pump running. Fuel pump may be operated with scan tool "Output Control" feature when fuel level is more than 20 percent and no DTCs are set.
3. 4
   
   This step checks fuel pressure after fuel pump stops. Approximately one minute after fuel pump stops, fuel pressure should remain steady above 25 psi (180 kPa). Fuel pump may be operated with scan tool "Output Control" feature when fuel level is more than 20 percent and no DTCs are set.
4. 5
   
   The vehicle should start and run. At this step, adequate fuel pressure is available for engine to operate. A vehicle that will not start may have inoperable fuel injectors.
5. 6
   
   This step checks for normal fuel pressure when engine is running. Fuel pressure that is not within specified value indicates a possible fault in fuel pressure regulator.
6. 8
   
   This step checks for a faulty check valve in fuel pump. Blocking (pinching) fuel feed hose between fuel pressure gauge and fuel pump, immediately after fuel pump stops, traps fuel pressure between fuel pressure regulator and blocked section. If fuel pressure now remains above specified value, fault is between blocked section and fuel tank. Fuel pump may be operated with scan tool "Output Control" feature when fuel level is more than 20 percent and no DTCs are set.
7. 9
   
   This step checks for a faulty fuel pressure regulator. Fuel pump may be operate with scan tool "Output Control" feature when fuel level is more than 20 percent and no DTCs are set.
8. 13
   
   A fault in fuel pump electrical circuit may cause low fuel pressure or no fuel pressure.
9. 14
   
   This step checks for additional conditions that can cause low fuel pressure other than a faulty fuel pump. Check for any restrictions or blockage in fuel feed lines and hoses, including those inside fuel tank. Check fuel pump electrical circuit for excessive resistance. Proper fuel pump operation requires correct voltage and adequate current flow.
10. 15
    
    This step checks operation of fuel pressure regulator. You may operate fuel pump with scan tool "Output Control" feature when fuel level is more than 20 percent and no DTCs are set.