2002 Cavalier Temperature Gauge Not Working?


Asked by May 04, 2013 at 02:53 AM about the 2002 Chevrolet Cavalier Base

Question type: Maintenance & Repair

I originally had posted this: http://www.cargurus.com/Cars/Discussion-t2089_ds545431?

However, I finally bought an OBD ii code scanner, and got code P0118 for "Electronic
Coolant Temperature (ECT) sensor circuit high input"

I tried replacing the ECT sensor (the 2 wire one/black and yellow) on the upper radiator
hose going into the engine.  That didn't resolve the problem.

What I have figured out is that every time the relay and cooling fan kick in, the TRAC
OFF light comes on and no matter how many times I reset it at that point, it will keep
coming back on.  Obviously this makes for a bad drive, with really hard shifts, etc.

The temperature GAUGE, however, doesn't work at all.  It just sits below 0.  It randomly
would work sporadically, but now just constantly sits at 0.

I heard there's another sensor with a single wire that's specifically for the gauge.  Could
that one be causing this?  I don't know where it's located.

Any other ideas?

5 Answers


http://www.obd-codes.com/p0118...mentions to check for 5V and a possible wiring issue. That's what I would say since your guage is reading 0. The TRAC light issue might be seperate, or related. It is usually related to the ABS system, and when the light is on, your Traction control is disabled. Have you scanned the codes when the TRAC light is on? I'd say you have something bigger going on. A bad ground, or a faulty PCM might be the issue. But at this point tracing the issue will be difficult if your a novice. I would have someone look at if you rely on this vehicle for everyday transporatation.

1 out of 1 people think this is helpful.

When I scan it when the TRAC OFF light is on, it's the same code, 0118, which is "Electronic Coolant Temperature (ECT) sensor circuit high input", no matter how many times I reset it, if that fan relay is on or kicks in, it comes on. When I first start the car, it isn't on until that relay kicks in. I also checked voltage on the harness, there is 5V. So since the gauge doesn't work, I'm guessing it has something to do with that, because everything works, sounds, and looks fine, and the fan obviously comes on, so it gets the reading from the ECT sensor on the coolant pipe. The gauge just doesn't work. People have said there's another sensor that is for the gauge that is elsewhere. Does anyone know where it is? There's the two wire one at the front by the alternator which is used by the computer for the relay, and supposedly there's another maybe single wire one that has to do with the gauge? Maybe that is shorting? I don't know where it is though.


The ECT (2-wire) signal is sent back to the PCM. The PCM uses the value for fuel calc's and to operate your fan. The A/C can also trigger the fan. Since that's code that it's spitting out I would test it again. With the 5V ref into the sensor piggyback to the output and verify that the reading starts at a certain value and changes smoothly as your engine warms up. Circuit high would make me think that the wires or switch were shorted together. Check continuity between the sensors pins. A low reading would indicate a short and high would be an open circuit. I think this are somewhere around 1000 ohms at room temp. Can't remember but I will check and get back to you. The single wire sensor only operates the gauge. They usually are threaded into the head and have a green pigtail 4" long to the engine harness. I will find it's location for you. Sometimes the pigtail or the harness touches the exhaust and melts. You are correct it will show zero when grounded. My 3.1/2.8 v-6's do this all the time. Check the wire. Tape it if the conductors are not broken and tie it out of the way. If the wires are good you may need a new sensor.

2 out of 2 people think this is helpful.
Best Answer

This is a great detailed answer that addresses my exact concerns. If you could find the locations for me that would be amazing. I typically do all my own car work as I'm on a very tight budget. The cav has 161k, got me across the country and gets me to auditions. I'm not going to give up on her yet.

1 out of 1 people think this is helpful.

Ok your temp indicator is a pain. I'm at work for a few days so I have limited resources. I can't find a pic anywhere for yah. It's got me stumped, for now. Back to your ECT. I usually test mine in water, heat it and check with a voltmeter. 32 F would be 10000 ohms, 86 at 2200 ohms and 212 at 176 ohms. So as your resistance goes down you get closer to a short, which would be your 5V ref to the PCM. Circuit high input. It has to be the sensor or the wiring. Maybe inspect the plug. Hope it's not worse like a PCM issue. Can your scanner read live values? If read that a dead short is around 300 F. A $5 10k ohm potentiometer would allow you to test the circuit.

1 out of 1 people think this is helpful.

Your Answer

Add photo

Related Questions

  • 2002 Chevy cavalier over heating. 4 answers

    I have a 2002 Chevy cavalier that does not over heat unless you run the air or sit to long. The fan is not kicking on. Where should I start.

    2002 Chevrolet Cavalier


    Maintenance & Repair

  • Temp Gauge Stuck 8 answers

    I've had temp gauge issues for the past two days (which coincides with -34C weather). Yesterday when I started my car after work, the temp gauge was already at the halfway mark. On the drive home, it ...

    2004 Chevrolet Cavalier Base


    Maintenance & Repair

  • 2002 cavalier won't start 15 answers

    2002 cavalier won't start. No crank. Lights work. Makes kinda of a crackling sound when trying to crank. Noise seems to be coming from right in front of dash under the hood.

    2002 Chevrolet Cavalier Base


    Maintenance & Repair

  • 2002 Chevy Cavalier won't Start and/or Turn over 4 answers

    Hey, My alternator went out on my 02 chevy cavalier. We changed it. It was fine that night. When i went to work in the morning I was on highway and all of a sudden my car highlights and gauges started...

    2002 Chevrolet Cavalier Base


    Maintenance & Repair

  • why has my temperature gauge stopped working 2 answers

    i have a 2002 chevy suburban 4x4 5.3l flex and my temperature gauge all of a sudden dosent move from 0 ni codes or lights have come on either what is wrong?

    2002 Chevrolet Suburban 1500 LS 4WD


    Maintenance & Repair


Looking for a Used Cavalier in your area?

CarGurus has 1,070 nationwide Cavalier listings and the tools to find you a great deal.


Search Chevrolet Cavalier Questions

Chevrolet Cavalier Experts

#1 John Saffrahn
John Saffrahn
Reputation 2,890
#2 dandyoun
Reputation 1,290
#3 mbar1
Reputation 1,170
View All

Related Models For Sale

Used Chevrolet Malibu
861 Great Deals out of 81,246 listings starting at $995
Used Chevrolet Impala
516 Great Deals out of 29,643 listings starting at $799
Used Honda Civic
500 Great Deals out of 89,147 listings starting at $1,299
Used Chevrolet Camaro
150 Great Deals out of 32,774 listings starting at $1,995
Used Honda Accord
781 Great Deals out of 87,732 listings starting at $1,150
Used Ford Focus
549 Great Deals out of 56,732 listings starting at $800
Used Ford Mustang
374 Great Deals out of 47,145 listings starting at $1,999
Used Pontiac Sunfire
323 listings starting at $1,295
Used Toyota Corolla
700 Great Deals out of 72,876 listings starting at $1,950
Used Chevrolet Silverado 1500
1,748 Great Deals out of 169,330 listings starting at $1,800
Used Dodge Neon
699 listings
Used Chevrolet S-10
14 Great Deals out of 1,365 listings starting at $1,595
Used Toyota Camry
844 Great Deals out of 90,577 listings starting at $850