How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Chris Your Own Question

Chris
Chris, Shop Foreman
Category: Jeep
Satisfied Customers: 9571
Experience:  Jeep and ASE Certified Master Tech
Type Your Jeep Question Here...
Chris is online now
A new question is answered every 9 seconds

98 Jeep Grand Cherokee: Coolant Sensor..Taillight..V8..5.2l with 212K

Customer Question

I keep getting the illusive "Coolant Sensor Bad" & "Rear Taillight Failure" Errors on my 98 Jeep Grand Cherokee V8 5.2l with 212K with Original Everything. The light error I don't care about, as all my lights are on, but I know its part of a bigger problem.

I'm a Med student just trying to get through school, my knowledge of cars is limited, so simple direction and cheap fixes would be much appreciated! Right now, I have replace both the Coolant sensor on the engine block and the Coolant float in the coolant overflow reservoir = little change. While the light used to remain on all the time, now almost each time I start up the car, for a few short minutes, the Coolant error will flash, then it goes away. I have driven the car over 100 miles so if something was gonna reset it should have kicked in by now right? However, I am still only getting 5-7 miles to the gallon no matter how "ginger" I drive, and before this issue I was getting 14-19 MPG. All other maintenance on the car is up-to-date. I have been told this is because the system is being thrust into "open-loop mode" by this error? I DO NOT want to, nore do I feel I have the skill to perform the below fix (see link) or even if that will truly fix my low gas issue... there must be another, simpler way to get the car into closed loop mode = (BETTER GAS mileage).

http://webcache.googleusercontent.com/search?q=cache:http://www.jeepforum.com/forum/f13/coolant-sensor-bad-finally-fixed-175207/

Thanks
Submitted: 2 years ago.
Category: Jeep
Expert:  Chris replied 2 years ago.
Hello and welcome to just answer. The coolant sensor message you are getting has absolutely nothing to do with your fuel economy or engine closed or open loop mode. It is for the coolant overflow bottle only. If your "check engine" light is not coming on then the fuel system is most likely going into closed loop. The cause of your poor fuel economy is something else like worn plugs, dirty air filter, lazy O2 sensor, dirty fuel injectors, etc. That coolant level sensor is in the bottle to alert you if the coolant level gets low. If there is a problem in that circuit then you get that coolant sensor bad message. It is most likely a wiring or connector problem at the sensor in the bottle.

I hope this information is helpful and let me know if you need further assistance with this.

Chris
Customer: replied 2 years ago.
hi thanks for your quick reply,

"That coolant level sensor is in the bottle to alert you if the coolant level gets low. If there is a problem in that circuit then you get that coolant sensor bad message. It is most likely a wiring or connector problem at the sensor in the bottle. "

I replaced the entire coolant sensor that goes inside the bottle and the wiring also, though it looked fine, yet I still get the error almost every time I start the car. Before the error I got good gas millage. after the error, poor gas mileage. It was a Jeep Mechanic at Dodge dealership that told me the coolant sensor would send it into, he called it "limp home mode." So I am honestly confused. The engine light is not on. However a 4/5 months ago, before the gas millage went hinky perform a tune up like 2000 miles ago, had all the spark plugs, cables, distributor cap, etc changed, and all was fine. Then start of last month, boom, here comes this coolant error and down goes my gas millage into the dump.

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • Thank you so much for your answer. My initial estimate was $325; I got it done for $100 - part and labor. Lynn B. Ormond Beach, FL
< Last | Next >
  • Thank you so much for your answer. My initial estimate was $325; I got it done for $100 - part and labor. Lynn B. Ormond Beach, FL
  • I was skeptical at first but thought I'd give it a try. I was pleasantly surprised. Your site actually is a quality service that I would recommend to others in a heartbeat. Stan Sayre, PA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
 
 
 

Meet The Experts:

 
 
 
  • Mark

    22 Year Factory trained technician

    Satisfied Customers:

    2548
    Jeep factory training........25 years in the industry.
< Last | Next >
  • http://ww2.justanswer.com/uploads/MO/MoparCertified/2012-6-7_4142_mechanic.64x64.jpg Mark's Avatar

    Mark

    22 Year Factory trained technician

    Satisfied Customers:

    2548
    Jeep factory training........25 years in the industry.
  • http://ww2.justanswer.com/uploads/jeep10000/2008-9-18_222938_192601.jpg Chris's Avatar

    Chris

    Shop Foreman

    Satisfied Customers:

    2265
    Jeep and ASE Certified Master Tech
  • http://ww2.justanswer.com/uploads/ke4ich/2009-08-12_212931_DSC02211.JPG moparfl's Avatar

    moparfl

    ASE Certified Technician

    Satisfied Customers:

    1128
    ASE Master Tech Chrysler Dodge Jeep Master Tech
  • http://ww2.justanswer.com/uploads/nvltgo/2010-10-18_211525_youranswers.jpg Dave's Avatar

    Dave

    Jeep Master Tech

    Satisfied Customers:

    1120
    Chrysler Triple Master, ASE master Tech AA degree in Auto.
  • http://ww2.justanswer.com/uploads/tsmodie/2009-6-10_144056_tim.jpg Tim Mohr's Avatar

    Tim Mohr

    ASE MASTER TECH

    Satisfied Customers:

    805
    30 YRS EXPERIENCE, FOREIGN AND DOMESTIC, GAS AND DEISEL
  • http://ww2.justanswer.com/uploads/CD/CDJMastertech/2012-6-9_201455_JustAnswerProfilelarger.64x64.JPG CDJMasterTech's Avatar

    CDJMasterTech

    Jeep MasterTech

    Satisfied Customers:

    576
    Factory trained and certified Jeep Master Technician, ASE Master Technician
  • http://ww2.justanswer.com/uploads/jeepmopar76/2009-3-18_2204_63998760.jpg jeepmopar76's Avatar

    jeepmopar76

    Jeep/Chrysler Triple Master Tech

    Satisfied Customers:

    572
    32yr ASE Master Tech, 9yr Chrysler Master Tech, 19 yr Jeep Dealership service including AMC/Eagle