Fuel Specific Gravity Testing
Use a J 38641-B Diesel Fuel Quality Tester to measure the fuel specific gravity (API Rating). Follow the instructions on the tool to obtain the proper temperature-adjusted value. This information must be accurate for the proper diagnosis of the fuel system.
Action Taken When the DTC Sets - Type A
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
Action Taken When the DTC Sets - Type B
The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.
Conditions for Clearing the MIL/DTC - Type A or Type B
- The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC Last Test Failed clears when the diagnostic runs and passes.
- Use a scan tool in order to clear the MIL and the DTC.
Action Taken When the DTC Sets - Type C
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The MIL will not illuminate.
- The driver information center, if equipped, may display a message.
Conditions for Clearing the DTC - Type C
- A last test failed, or current DTC, clears when the diagnostic runs and passes.
- Use a scan tool in order to clear the DTC.
Conditions for Clearing the DTC - Type X
- This DTC is available in the PCM software, but has been disabled, or turned OFF. In this case, the diagnostic does not run, no DTCs are stored, and the MIL does not illuminate. Type X DTCs are used primarily for export vehicles that do not require MIL illumination or DTC storing.
Diagnostic Trouble Code (DTC) Type(s)
| DTC Code | RPO FE9, NG1 | RPO YF5, NE1 |
|---|---|---|
| P0016 | C | C |
| P0087 | A | A |
| P0088 | A | A |
| P0089 | C | A |
| P0090 | A | A |
| P0101 | C | B |
| P0102 | B | B |
| P0103 | B | B |
| P0112 | B | B |
| P0113 | B | B |
| P0116 | X | B |
| P0117 | B | B |
| P0118 | B | B |
| P0128 | X | A |
| P0168 | C | C |
| P0181 | B | B |
| P0182 | A | A |
| P0183 | A | A |
| P0192 | A | A |
| P0193 | A | A |
| P0201-P0208 | A | A |
| P0234 | B | B |
| P0236 | C | B |
| P0237 | B | B |
| P0238 | B | B |
| P0300 | C | B |
| P0301-P0308 | C | B |
| P0335 | A | A |
| P0336 | B | B |
| P0340 | A | A |
| P0341 | B | B |
| P0370 | A | A |
| P0374 | A | A |
| P0380 | C | B |
| P0381 | C | B |
| P0401 | X | B |
| P0404 | X | B |
| P0405 | X | B |
| P0406 | X | B |
| P0461 | C | C |
| P0462 | C | C |
| P0463 | C | C |
| P0489 | X | B |
| P0490 | X | B |
| P0500 | B | B |
| P0522 | C | C |
| P0523 | C | C |
| P0530 | C | C |
| P0540 | B | B |
| P0543 | B | B |
| P0562 | C | C |
| P0563 | C | C |
| P0567 | C | C |
| P0568 | C | C |
| P0571 | C | C |
| P0601 | A | A |
| P0602 | A | A |
| P0603 | C | C |
| P0604 | A | A |
| P0611 | B | B |
| P0612 | B | B |
| P0621 | C | C |
| P0622 | C | C |
| P0641 | A | A |
| P0650 | A | A |
| P0651 | B | B |
| P0700 | A | A |
| P0802 | B | B |
| P0833 | C | C |
| P1093 | C | A |
| P1094 | C | C |
| P1125 | C | C |
| P1172 | C | C |
| P1223 | C | B |
| P1226 | C | B |
| P1229 | C | B |
| P1232 | C | B |
| P1235 | C | B |
| P1238 | C | B |
| P1241 | C | B |
| P1244 | C | B |
| P1270 | C | C |
| P1404 | X | B |
| P1550 | C | C |
| P1621 | C | C |
| P1626 | C | C |
| P1631 | C | C |
| P1637 | C | C |
| P1658 | A | A |
| P2066 | C | C |
| P2067 | C | C |
| P2068 | C | C |
| P2122 | C | C |
| P2123 | C | C |
| P2127 | C | C |
| P2128 | C | C |
| P2132 | C | C |
| P2133 | C | C |
| P2138 | C | C |
| P2139 | C | C |
| P2140 | C | C |
| P2141 | X | B |
| P2142 | X | B |
| P2144 | X | B |
| P2145 | X | B |
| P2146 | A | A |
| P2149 | A | A |
| P2227 | C | B |
| P2228 | B | B |
| P2229 | B | B |
| P2279 | X | B |
| P2610 | B | B |
| U1800 | C | B |
| U2104 | C | B |
| U2106 | C | B |
Diagnostic Trouble Code (DTC) Type(s)
Scheme 267
| Callout | Component Name |
|---|---|
| 1 | EGR Vacuum Sensor |
| 2 | EGR Throttle Valve Vacuum Control Solenoid |
| 3 | EGR Throttle Valve Diaphragm |
| 4 | EGR Valve Vacuum Control Solenoid |
| 5 | EGR Vacuum Vent Solenoid |
| 6 | EGR Valve Diaphragm |
| 7 | Vacuum Pump |
Scheme 268
| Callout | Component Name |
|---|---|
| 1 | Fuel Rail |
| 2 | Fuel Junction Block |
| 3 | Fuel Injector |
| 4 | Fuel System Cooler |
| 5 | Fuel Tank |
| 6 | Fuel Injection Control Module |
| 7 | Fuel Filter |
| 8 | First Start Fuel Bleeder Valve |
| 9 | Fuel Injection Pump |
Fuel Injector Cleaning and Inspection
| IMPORTANT | If reusing the old injectors perform the following |
- Use a soft bristle non-metallic brush and top engine cleaner, GM P/N 1052626 (Canadian P/N 993026) or equivalent, to remove any deposits from the nozzle tip (1) and the copper washer sealing area (2) before re-installation.
- Inspect the fuel injector nozzle tip (1) for any signs of discoloration (dark yellow, tan, or blue) due to excessive heat.
- Replace the injector if any damage is found.
- Clean the fuel injector high pressure line.
- Inspect the fuel injector high pressure line for excessive corrosion or damage to the sealing surfaces (1, 2). Replace the line if any damage is found.
Diagnostic System Check - Engine Controls
The Diagnostic System Check - Engine Controls is an organized approach to identify a problem caused by an electronic engine control system malfunction. This diagnostic check must be the starting point for any driveability complaint diagnosis. The diagnostic directs the technician to the next logical step in diagnosing the complaint.
Use the Engine Scan Tool Data Definitions list for a comparison after fulfilling the following items
- Complete the Diagnostic System Check-Engine Controls.
- Confirm that the on-board diagnostics are functioning properly.
- Confirm there are no diagnostic trouble codes.
The Engine Scan Tool Definitions are an average of display values recorded from normal operating vehicles. The definitions intend to represent what a normal functioning system should display.
| IMPORTANT | Do not use a scan tool that displays faulty data. Report the problem to the manufacturer. Using a malfunctioning scan tool can result in misdiagnosis and unnecessary parts replacement. Use only the parameters listed in the Engine Scan Tool Data Definitions for diagnosis. When a scan tool reads other parameters, General Motors recommends not using the values for use in diagnosis. For more description on the values and the use of the scan tool to diagnose the ECM inputs, refer to the applicable diagnostic file. When all the values are within the range illustrated in the Engine Scan Tool Data Definitions, refer to Symptoms - Engine Controls . |