Test Description

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

1. 1
   
   The Diagnostic System Check - Engine Controls prompts the technician to complete some basic checks and store the freeze frame data on the scan tool, if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. 6
   
   This step checks the fuel pump for a worn bearing or a binding impeller. The pump should have a smooth and steady low humming sound. A loud humming or growling noise may indicate a faulty fuel pump. Check a known good vehicle to compare pump operation.
3. 12
   
   The fuel system cannot maintain constant fuel pressure with a leak in any of the following areas:
   • The fuel pump check valve.
   • The valve or valve seat within the fuel pressure regulator.
   • The fuel injectors.
4. 17
   
   This step checks whether the fuel system is leaking between the fuel pressure gauge and the fuel injectors or between the fuel pressure gauge and the fuel sender assembly.
5. 20
   
   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 the fuel feed lines and hoses, including those inside the fuel tank. Check the fuel pump electrical circuit for excessive resistance. Proper fuel pump operation requires correct voltage and adequate current flow.
6. 23
   
   Check for rust and other foreign materials in the fuel tank. Clean or replace the fuel tank as necessary.