| Tools Needed | Quantity | |
| 1U-5470 Engine Pressure Group | 1 | |
Absolute pressure - Absolute pressure is the gauge pressure plus the local barometric pressure.
Gauge pressure - Gauge pressure is the absolute pressure minus the local barometric pressure.
The inlet manifold pressure sensor measures the absolute inlet manifold air pressure. The EIS control module uses information from the inlet manifold pressure sensor to calculate the engine load.
To verify that the inlet manifold pressure sensor is accurate, use the DDT to read the inlet manifold air pressure when the engine is stopped. The correct pressure will be the ambient barometric pressure.
The inlet manifold air pressure can be measured from more than one location.
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| Illustration 1 | g00819950 |
Plug near the front of the cylinder head | |
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| Illustration 2 | g00819936 |
(1) Plug (2) Plug | |
Note: There will be a difference in the pressure that is measured at plug (1) and plug (2). This is because of a slight restriction of the air through the aftercooler.
Remove a plug near the front of the cylinder head or from the aftercooler. Connect a line from the opening to a pressure gauge from the 1U-5470 Engine Pressure Group. Operate the engine under a load. Use the DDT to read the inlet manifold air pressure. Read the pressure gauge from the 1U-5470 Engine Pressure Group and add the local barometric pressure to the reading. Compare the calculation to the reading from the DDT.