GM Truck Club
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Results 1 to 5 of 5
  1. #1

    Default Flashing engine light

    Hi All,
    Every time I run my truck (2003 Yukon XL 5.3l) through the local touchless car wash The engine light flashes. I as soon as I pull out of the wash it goes off. My programer that I use to read codes shows nothing. It only happens when I do the "Works" Wash. (the longest one they have). Any ideas? I guess that I could just shut it off while in the wash and avoid the issue all together. Thanks

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  2. #2


    A flashing check engine light means that your engine is misfiring... and it should come with a code. My 2001 Silverado had a flashing check engine light until I did a bunch of maintenance on it, and that light came with a p0300 code - random/multiple misfire. So, I would check anything ignition related that the car wash could be messing with... ignition coils, spark plugs, wires, etc. and check to see if there is any way the moisture could be affecting any of those components.

    2008 FORD F350. My new all-around truck.
    2001 Silverado Reg. Cab Not-So-Base -- SOLD
    2003 Avalanche Z71. No Cladding. Check out my Mod thread. - Crashed. Will be rebuilt soon.
    1974 Triumph Spitfire 1500 - Work in Progress
    2003 Sierra 3500 Duramax. The Newer, Better Work Truck -- FOR SALE

  3. #3


    I will try to replicate the problem in my driveway at night by spraying some water mist on the ignition components while the engine is idling and check for a light show (sparking or arcing) that would cause the engine light to flash. How many miles? Ignition wires could be getting tired.
    Good Luck!

  4. #4


    If the car wash is blasting the bottom of your vehicle, it is likely causing a problem with the O2 sensor. It will cause the engine light to flash if it is getting a catalyst performance code too. Just an idea.
    "It went together didn't it? Well then there has to be a way to take it apart!" - Me.

    Check out my image gallery HERE.

    "The true measure of a man is how he treats someone who can do him absolutely no good." ~Samuel Johnson (1709-1784)

  5. #5


    I have tried spraying the motor down at night in the driveway. I get nothing. It has 145,000. the wires are not the original. I might have to crawl under there and spray along the exhaust area. I am leaning towards an 02 sensor issue. I can take it thru a soft cloth car was with no issue (except scratching the crap out of it). I have driven thru a few rainstorms that were so heavy people were pulling over on the freeway. The light will only turn on in that wash. I actually just left there. I shut it off this time and got no light. Next time I will put my programmer in monitor mode and watch for any crazy readings from 02 sensors, mass air flow. There are no codes stored. Thanks guys.
    Last edited by Pikey; 04-25-2012 at 02:55 PM.

Similar Threads

  1. Flashing brake light AND no DRL
    By travisn in forum GM Electrical Tech
    Replies: 5
    Last: 11-27-2011, 08:52 PM
  2. Brake light flashing
    By RangerJ in forum Chevy Truck Tech Forum
    Replies: 1
    Last: 08-12-2010, 06:10 AM
  3. 99 silverado with flashing check engine light
    By rotax583 in forum General Chevy & GM Tech Questions
    Replies: 13
    Last: 07-18-2010, 09:44 PM
  4. ABS and Check Engine Light Flashing Once along with a *Ding*
    By rockhopjohn in forum General Chevy & GM Tech Questions
    Replies: 0
    Last: 02-07-2010, 12:00 PM
  5. 02 Silverado: Flashing service light, wont shift from 1st to 2nd????
    By agent47_tjr in forum Chevy Silverado Forum (GMC Sierra)
    Replies: 6
    Last: 12-17-2008, 05:21 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts