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For 1990-2009 cars only

Fuel Gauge Fluctuation in Park or Neutral - keywords gage inaccurate intermittent IP IPC

Subject:Fuel Gauge Fluctuation In Park Or Neutral

Models:2004-2006 Buick Rainier
2002-2006 Cadillac Escalade, Escalade EXT
2003-2006 Cadillac Escalade ESV
1999-2005 Chevrolet Astro
2002-2006 Chevrolet Avalanche
1998-2004 Chevrolet Blazer Classic
2004-2006 Chevrolet Colorado
2001-2004 Chevrolet S10 Crew-Cab
1998-2003 Chevrolet S-10 Pick-Up
1999-2006 Chevrolet Silverado
2000-2006 Chevrolet Tahoe, Suburban
2002-2006 Chevrolet Trailblazer
2002-2006 GMC Envoy
1998-2001 GMC Envoy Classic
2004-2006 GMC Canyon
1998-2004 GMC Jimmy Classic
1999-2005 GMC Safari
1999-2006 GMC Sierra
1998-2003 GMC Sonoma
2001-2003 GMC Sonoma Crew-Cab
2000-2006 GMC Yukon, Yukon XL
2002-2004 Oldsmobile Bravada
1998-2001 Oldsmobile Bravada Classic
2003-2006 Hummer H2
2005-2006 Hummer H2 SUT



This PI has been revised to add additional models. Please discard PIT3046C.


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

  1. On a Automatic Transmission no buffering takes place when the transmission is in park or neutral. This is a NORMAL characteristic & NO repairs are necessary.
  2. 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.