Actual Fuel Economy Lower Than The EPA Fuel Economy Estimate - keywords BAS ECO gas gasoline HP2 hybrid LAT light low poor
| Subject: | Actual Fuel Economy Lower than the EPA Fuel Economy Estimate |
| Models: | 2007 Saturn VUE Greenline Hybrid |
| with 2.4L Engine (VIN Z - RPO LAT) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
On rare occasions, a customer may complain that their fuel economy is less than the EPA fuel economy estimate. Although the VUE Greenline Hybrid is rated at 27 MPG city and 32 MPG highway (8.8 L/100 km city and 6.7 L/100 km highway in Canada), fuel economy can vary greatly depending upon how the vehicle is driven. The measurement of fuel economy during vehicle break-in will typically generate lower numbers. Measured fuel economy will generally stabilize after the first 1000 miles (1600 km).
Recommendation/Instructions:
If the Poor Fuel Economy symptom section of the SI diagnostics do not isolate a cause for this concern, perform the following as necessary:
| • | Verify proper tire pressures and adjust as necessary. |
| • | Verify that stock tires and wheels are on the vehicle. They should be General Ameri GS60 tires (215/70R/16). |
| • | Ensure that the latest ECM calibrations are installed. Although there are no improvements included in this calibration to specifically improve fuel economy, the calibration does improve cruise control performance as outlined in PIP4010. As a result, it may improve fuel economy when the cruise control is used in hilly/mountainous areas. |
| • | Ensure that the spoiler was installed during the Pre-Delivery Inspection as mentioned in 06-00-89-044. |
| • | Check for proper Auto-Stop operation during a test drive at operating temperature. If necessary, refer to the "Conditions Required for an Auto-Stop Reasons for No Auto-Stop or Early Auto-Start" section of 06-00-89-044 for more information on Auto-Stop operations, and reasons why it may be inhibited if there are no DTCs present. |
| • | Accessories like roof racks will result in reduction of fuel economy due to reduced aerodynamic performance. |
| • | Check for added weight on the vehicle from add on accessories and/or cargo. |
| • | Inspect all four brakes for excessive brake drag. With vehicle on hoist, the rear wheels should spin freely and the front wheels should rotate by hand with the transmission in neutral. |
| • | Check the vehicle trim height by following the Trim Height Inspection procedure in SI. |
| • | Fuels with ethanol blends will result in slightly lower fuel economy due to lower BTU or energy content.Cold starts will lower fuel economy due to fuel enrichment during cold start. Also, engine warm up reduces fuel economy. |
| • | Using the defrost will command the A/C compressor on to remove humidity and defrost windows, which inhibits auto-stop. This reduces fuel economy due to the extra load of the A/C compressor and lack of auto-stop operation.
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| • | Review the "How to Maximize Fuel Economy" section of bulletin 06-00-89-044 with the customer, which explains ECO light operation, and how fuel economy is affected by driving habits and use of the HVAC system. |
| • | US Dealers should visit http://www.fueleconomy.gov/ for more information on fuel economy and review it with the customer**. This is a government website that contains information for all makes and models and it contains some great information that answers several questions regarding fuel economy. The section titled "Gas Mileage Tips" gives some great advice on efficient driving, proper vehicle maintenance, using the correct engine oil, and keeping the tires inflated properly, The section titled "Why Your MPG Will Vary" explains: why the actual fuel MPG is typically less than the EPA fuel MPG, many factors that affect MPG, EPA fuel economy ratings, which vehicles are tested by the EPA, how vehicles are tested by the EPA, and it outlines the driving schedule for the city and highway EPA tests. |
| • | Canada Dealers should review the Office of Energy Efficiency, Personal Transportation at http://oee.nrcan.gc.ca/transportation/personal/ (English) or http://oee.nrcan.gc.ca/transports/personnel/ (French) |
| • | Review the customer's driving habits. If they drive in hilly/mountainous areas, drive aggressively, use the heated seats often, let the engine idle in park to warm up the engine, use the defrost/air conditioning, their fuel economy may decrease as a result of their driving habits. |
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
