Fuel Gauge Fluctuation In Park Or Neutral (PIT3046G)

Publication date: 2015-02-27
Reference number: PIT3046G

FUEL GAUGE FLUCTUATION IN PARK OR NEUTRAL

TECHNICAL SERVICE BULLETIN

Reference Number(s): PIT3046G, Date of Issue: February 27, 2015

AFFECTED MODEL(S):

2008-2015 Buick Enclave; 2004-2007 Buick Rainier; 2005-2007 Buick Terraza; 2002-2009 Cadillac Escalade models; 1999-2005 Chevrolet Astro, GMC Safari; 1998-2009 Chevrolet Blazer Classic and Trailblazer models, GMC Envoy and Envoy Classic models; 2004-2012 Chevrolet Colorado, GMC Canyon; 2015 Chevrolet Colorado, GMC Canyon; 2005-2015 Chevrolet Equinox; 2001-2005 Chevrolet S10 Crew-Cab and S-10 Pick-Up models, GMC Sonoma and Sonoma Crew-Cab models; 1999-2015 Chevrolet Silverado, Silverado Classic, GMC Sierra and Sierra Classic models; 2000-2015 Chevrolet Tahoe, Suburban, GMC Yukon models; 2009-2015 Chevrolet Traverse; 2005-2009 Chevrolet Uplander, Pontiac Montana SV6; 2007-2015 GMC Acadia; 1998-2005 GMC Jimmy Classic; 2010-2015 GMC Terrain; 2002-2004 Oldsmobile Bravada; 1998-2001 Oldsmobile Bravada Classic; 2006-2009 Pontiac Torrent; 2007-2010 Saturn Outlook; 2005-2008 Saturn Relay; 2003-2009 Hummer H2 and H2 SUT models; 2006-2010 Hummer H3 models

SUPERCEDES:

This PI was superseded to update Models. Please discard PIT3046F

SERVICE INFORMATION

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

CONDITION/CONCERN

Fuel gauge may be inaccurate or drops to empty (E) and the low fuel light comes on.

Further analysis may reveal that this condition is most apparent when the gauge is at or below the quarter (1/4) tank mark.

RECOMMENDATION/INSTRUCTIONS

Try to duplicate the concern by driving the vehicle a short distance in reverse and then stopping (to make fuel slosh), shifting transmission to park or neutral and then shifting to drive.

The fuel gauge will have a tendency to falsely indicate a lower fuel level than what is actually present

The gauge will take a few minutes to show the actual fuel level. The VCM/PCM is the buffer for the fuel gauge.

It should also be noted how the vehicle is being parked (i.e. on an incline, front of veh up hill or down hill, etc..) Also note if the gauge works properly after cycling the key on level ground.

On an Automatic Transmission no buffering takes place when the transmission is in park or neutral. This is a NORMAL characteristic & NO repairs are necessary.
On a Manual Transmissions, the fuel gauge is buffered in all gears and neutral. Since the VCM/PCM has no way to know what gear it is in, there is a timer which starts to count up when the clutch is depressed. When this timer reaches its calibrated value (this value will vary), the filtering switches to the "fast" filter (no buffering). When the clutch is releases the filter then switches to the slow filter (system is buffered). This is a NORMAL characteristic & NO repairs are necessary.
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.