Inspection
| Action
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DEFINITION: Fuel economy, as measured by actual road tests and several tanks
of fuel, is noticeably lower than expected. Also, the economy is noticeably lower
than it was on this vehicle at one time, as previously shown by actual road tests.
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Preliminary Inspection
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| • | Inspect the air filter for dirt or being plugged. |
| • | Inspect for an air leak in the charge air cooler with a J 46091
Charge Air Cooler Tester. |
| • | Inspect the air conditioning system for proper operation. |
| • | Inspect the tires for correct air pressure. |
| • | Inspect the driving habits of the owner. |
| • | Are heavy loads being carried? |
| • | Suggest to the owner to fill the fuel tank and inspect the fuel economy. |
| • | Suggest to the driver to read the Important Facts on Fuel Economy in the
Owner Manual. |
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Sensor Inspection
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| • | Observe the fuel rail pressure (FRP) sensor and the fuel pressure regulator
commanded percent at idle. FRP should be near 40 MPa, and commanded percent
should be near 40 percent. If the command is high, a fuel pressure or sensor
concern exists. |
| • | Inspect the CKP sensor reluctor wheel. Remove the CKP sensor and attempt
to move the reluctor wheel front to back or side to side with a probe. If there is
any movement the reluctor wheel retaining bolts are loose. |
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Fuel System Inspection
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| • | Inspect the fuel type and quality. |
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Cooling System Inspection
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| • | Inspect the engine coolant level. |
| • | Inspect the engine thermostats for always being open or for the wrong
heat range. Refer to
Thermostat Diagnosis
in Engine Cooling. |
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Additional Inspection
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| • | Inspect the transmission for proper operation. |
| • | Inspect the torque converter clutch (TCC) operation. When the TCC is commanded
ON, a scan tool should indicate an RPM drop. |
| • | Inspect the Service Bulletins for control module software updates. |
| • | Inspect the brake for proper operation. |
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