Checks
| Action
|
Definition:
The fuel economy, as measured by an actual road test, is noticeably lower
than expected. Also, the economy is noticeably lower than it was on this vehicle
at one time, as previously shown by an actual road test.
|
Preliminary Checks
|
| • | Check the air cleaner filter for dirt or being plugged. |
| • | Visually (physically) check: The vacuum hoses for splits, kinks,
and proper connections. |
| • | Perform the Powertrain On-Board Diagnostic System Check. |
| • | Check the driving habits of the owner. |
| • | Is the A/C ON full time (is the defroster mode ON)? |
| • | Are the tires at the correct pressure? |
| • | Are any excessively heavy loads being carried? |
| • | Is the acceleration too much, too often? |
| • | Suggest to the owner to fill the fuel tank and recheck the fuel
economy. |
| • | Suggest to the driver to read the Important Facts on Fuel Economy
in the Owner Manual. |
|
Fuel System
Checks
|
| • | Check the fuel type and quality. Refer to Fuel Quality Diagnosis
. |
| • | Check the fuel pressure. Refer to Fuel Supply System Check
. |
|
Cooling
System Checks
|
| • | Check the engine coolant level. |
| • | Check the engine thermostat for always being open or for the wrong
heat range. |
|
Additional
Checks
|
| • | Check the transmission shift pattern. |
| • | Check the Torque Converter Clutch (TCC) operation. When the TCC
is commanded ON, a Scan Tool should indicate an RPM drop. |
| • | Check the Service Bulletins for any control module software updates. |
| • | Check for dragging brakes. Refer to the appropriate service manual. |
|
