MODEL IDENTIFICATION
Vehicle model is identified by the fifth character of Vehicle Identification Number (VIN). The VIN is stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION table.
| Series (1) | Model |
|---|---|
| "C" | 2WD Avalanche, Escalade, Sierra, Silverado, Suburban, Tahoe, Yukon & Yukon XL |
| "G" | RWD Chevy Express & Savana |
| "H" | AWD Chevy Express & Savana |
| "K" | AWD/4WD Avalanche, Escalade, Escalade ESV, Escalade EXT, Sierra, Silverado, Suburban, Tahoe, Yukon & Yukon XL |
| "N" | Hummer H2 |
| "S" | Envoy XL & TrailBlazer EXT (2WD) |
| "T" | Envoy XL & TrailBlazer EXT (AWD/4WD) |
| (1) Vehicle series is fifth character of VIN. | |
| (1) | Vehicle series is fifth character of VIN. |
MODEL IDENTIFICATION
Description
Water contamination in the fuel system may cause driveability conditions such as hesitation, stalling, no start, or misfires in one or more cylinders. Water may collect near a single fuel injector at the lowest point in the fuel injection system and cause a misfire in that cylinder. If the fuel system is contaminated with water, inspect the fuel system components for rust or deterioration.
Ethanol concentrations of greater than 10 percent can cause driveability conditions and fuel system deterioration. Fuel with more than 10 percent ethanol could result in driveability conditions such as hesitation, lack of power, stalling , or no-start. Excessive concentrations of ethanol used in vehicles not designed for it may cause fuel system corrosion, deterioration of rubber components, and fuel filter restriction.
Test Description
Water contamination in the fuel system may cause driveability conditions such as hesitation, stalling, no-start, or misfires in one or more cylinders. Water may collect near a single fuel injector at the lowest point in the fuel injection system and cause a misfire in that cylinder. If fuel system is contaminated with water, inspect fuel system components for rust or deterioration.
Ethanol concentrations of greater than 10 percent can cause driveability conditions and fuel system deterioration. Fuel with more than 10 percent ethanol could result in driveability conditions such as hesitation, lack of power, stalling , or no-start. Excessive concentrations of ethanol used in vehicles not designed for it may cause fuel system corrosion, deterioration of rubber components, and fuel filter restriction.
System Description
The scan tool is first used to energize the fuel pump relay. The fuel injector tester is then used to pulse each injector for a precise amount of time, allowing a measured amount of fuel into the manifold. This causes a drop in system fuel pressure that can be recorded and used to compare each injector.
The number below refers to step number in diagnostic procedure.
- 3 - Engine Coolant Temperature (ECT) must be below operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.
Scheme 29
Scan tool first energizes fuel pump and then injectors for a precise amount of time allowing a measured amount of fuel into manifold. This causes a drop in system fuel pressure that can be recorded and used to compare each injector.
The numbers below refer to step numbers in diagnostic procedure.
- 5 - If the pressure drop value for each fuel injector is within 1.5 psi (10 kPa) of the average pressure drop value, the fuel injectors are flowing properly. Calculate the pressure drop value for each fuel injector by subtracting the second pressure reading from the first pressure reading.
The numbers below refer to step numbers on diagnostic procedure.
- 3 - This step determines if condition is located on coil side or on switch side of fuel pump relay.
- 4 - This step verifies that PCM is providing voltage to fuel pump relay.
- 5 - This step tests for an open in ground circuit to fuel pump relay.
- 6 - This step determines if a voltage is constantly being applied to fuel pump relay.
- 13 - This step determines if condition with circuit is intermittent.
Fuel tank leak test is used to locate any fuel or fuel vapor escaping fuel tank area. Fuel vapors escaping above fuel level will be detected when Evaporative (EVAP) emission diagnostics complete one test cycle. Malfunction Indicator Light (MIL) will illuminate after EVAP diagnostics complete 2 test cycles.
The numbers below refer to step numbers in diagnostic procedures.
- 1 - Perform this procedure in order to determine that no EVAP diagnostic DTC is present.
- 3 - This test is to locate fuel leakage in fuel lines.
- 4 - This tests for fuel leaks below fuel tank fuel level.
- 5 - This test is to locate fuel vapors escaping above fuel level in fuel tank.