Test Description
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Savana, 2003 Chevrolet Silverado, and 2003 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to step numbers on diagnostic procedure.
- 2 - This step verifies that the HPL solenoid and the FTP sensor are functioning. A fuel tank pressure value that decreases while the engine is operating indicates the HPL is not opening or the manual tank valve is closed.
- 3 - This step verifies the FRP sensor is displaying the correct fuel pressure.
- 4 - This step tests for a leak in the fuel system between the LPL and fuel injectors. The fuel pressure should remain constant during the test.
- 5 - This step tests the HPR output pressure. If the fuel pressure is within the specified values, then the HPR, fuel lines, and filters are okay.
- 6 - This step tests the operation of the AF lock-off relay controlling the HPL solenoid.
- 9 - This step tests the operation of the AF lock-off relay controlling the LPL solenoid.
- 13 - This step verifies that a fuel filter is not the cause of the condition. If fuel pressure is within the specified range after the fuel filter replacement, then a plugged filter was the cause of the condition.