P0179 - Fuel Comp Sensor 04 Suburban

Discussion in 'GM Powertrain' started by Crazeetxn, Jan 21, 2010.

  1. Crazeetxn

    Crazeetxn Rockstar

    Morning All -

    About 2 days before Christmas, our 04 Suburban 5.3 (100K miles) wouldn't start. Engine light came on so I hooked up a diag reader and got a P0179 - Fuel Compostion Sensor...Come to find out, all it's used for is to tell the computer if your're running flex fuel or not...not a station within 200 miles so NO, I don't run it. Anyway...I cleared the code and after a few more attempts it fired and ran for about a week or so. Then wouldn't start. Cleared the code again, put some fuel treatment in thinkiing it could be bad gas too and of course it ran...then died...then ran...then died.

    Question is, what's the best way to go about replacing this? I belive I located it under the driver's side just before the firewall. Looks simple enough, but I have to find the part...any suggestions or recommendations when dealing with this absolutely useless part? I found something called a replicator, but haven't seen much about it.

    Thanks in advance,

  2. Sky

    Sky New Member

    The below paste is a post I put on Tahoe Yukon Forum earlier today. 3 years ago, when my Yukon was near the same mileage as yours, I experienced the same problems you are now having. After a lot of back and forth to GMC I gave in and replaced the sensor. Before I did the problem got worse, with more frequent hard starts and the check engine light staying on longer. The sensor is expensive, about $800. The end up was the sensor was indeed, bad. But now it seems the same problems are coming back and I would think GM would have a service bulletin on this! Good luck with your Suburban Troy. Aside from this problem, and HVAC control head issues, these are great trucks!


    My '04 Yukon 5.3 Vortec, 171K miles is showing a DTC P0179, which is the Fuel Compensation Sensor.

    The dealer replaced this sensor 3 years ago at 106K miles at a substantial cost ($1,000) when hard starting problems arose and the check engine light would not turn off.

    About 3 weeks ago the check engine light came on, the engine started hard, and P0179 was the stored code. This was an isolated incident, and the light shut off. However, my scan tool shows P017 as a pending code. I am concerned that the sensor is acting up again, and I may experience the same issues as 3 years ago - frequent hard starts and the check engine light staying on.

    My fuel filter was last replaced at 97K. Could this be the cause?

    Has anyone else experienced this problem with this sensor? If so, how often have you replaced the sensor? Is there one available at a lower cost?
  3. kennyb79

    kennyb79 Rockstar 100 Posts

    so can you guys shed some light on tghis for me...I was told that my sensor is swollen and starting to crack due to corrosion? by the garage that changed my fuel lines...any insight would be appreciated
  4. Sky

    Sky New Member

    P0179 - Fuel Comp Sensor 04 Yukon; Bypass Sensor by Point A Engineering

    This is further to my post of 1/15/11. My Yukon now has 220,000 miles and the Check Engine Light is on more than off, with code P0179. I replaced the fuel filter twice since 2011, with no effect on the light/code. I still can not solve this problem. The Truck runs fine, but there is an occassional hard start, necessitating pressing down the gas pedal while cranking the engine.

    There is a bypass available from Point A Engineering for $150. Has anyone tried this? What are the results?

    Comments or advice is appreciated. Thanks for reading.

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