Emission's

Asked by Jun 11, 2016 at 11:15 AM about the 1998 Honda Civic EX

Question type: Maintenance & Repair

I have a 98 Honda civic ex 1.6 d16y8, when I got
the car it had one code p0118 witch is for the temp
sensor, and the 02sensor cat and 02htr monitor
was not ready. So I replaced the 02sensor drove it
for 10 20 miles then hooked it up to the obd reader
and all three of those monitors were ready, but
then I shut my car off and fired it back up read it
again and the monitors went back to not ready. If I
drive it for 10 miles they will go back to ready and
will stay ready till I shut the car off its a repeated
cycle. I got 2 days left on my 10 day inspection can
anyone help me out? I also have the temp sensor
on its way through the mail, could that be messing
with the cat and 02 monitors? Also at times when I
start my car up the check engine light will be off
and the p0118 code will not come up till I shut off
the car and start it back up.

5 Answers

42,765

P0118 1998 HONDA CIVIC - Engine Coolant Temperature Sensor 1 Circuit High Voltage..... Possible causes - Low Engine Coolant Level - Faulty Engine Coolant Temperature (ECT) sensor - Faulty Engine Coolant Thermostat - Engine Coolant Temperature (ECT) sensor harness is open or shorted - Engine Coolant Temperature (ECT) sensor electrical circuit poor connection..... First check to see if there are any coolant leaks and if the thermostat is opening, if problem is still there replace the coolant temperature sensor....P0118 1998 Honda Civic Description.... The Engine Coolant Temperature (ECT) sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the Engine Control Module (ECM). The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.

Thanks for the temp sensor aspect of the problem I know the wires and plug are okay for it, I will check the thermostat. But the main thing I'm trying to find out is the 02 sensor and catalyst montioners goi g from ready to not ready like how I dercribed in my question, do you have any ideas of what's going on with that?

42,765

I know the engine temperature needs to be at operating temp. and without the temperature sending unit not operating correctly, all other sensors will not operate correctly as the computer adjusts all other sensors according to what the TSU is feeding the computer. It just may be that replacing the TSU would take care of the problem.

11,015

Incorrect Info! all sensor are functional and operate fine regardless of "TSU" the computer is fully operational regardless of what a coolant temperature sensor sends or doesn't send. Lots of good engineering books and training materiel out there. Regards

42,765

Ok, a bad choice of words. Not that the other sensors would operate incorrectly, or the computer, but the computer would adjust to what it thinks the engine temp. is at. What I was trying to say is if the TSU is open or bad, it may explain why the 02 sensor is in the ready & not ready state, as between the 02 & the TSU are what is telling the computer how to adjust for the air fuel mixture.

Your Answer

Add photo

Related Questions

Civic

Looking for a Used Civic in your area?

CarGurus has 69,478 nationwide Civic listings starting at $1,200.

ZIP:

Search Honda Civic Questions

UK Questions

Are you a UK consumer? CarGurus now has a discussion forum in the UK.

Honda Civic Experts

#1 Takoda Fraser
Takoda Fraser
Reputation 960
#2 Jonathan Ford
Jonathan Ford
Reputation 950
#3 Tom Demyan
Tom Demyan
Reputation 900
View All

Related Models For Sale

Used Honda Accord
988 Great Deals out of 74,848 listings starting at $899
Used Honda Civic Coupe
229 Great Deals out of 18,175 listings starting at $1,500
Used Toyota Corolla
989 Great Deals out of 66,021 listings starting at $1,595
Used Toyota Camry
1,181 Great Deals out of 95,093 listings starting at $1,250
Used Honda CR-V
838 Great Deals out of 63,787 listings starting at $1,100
Used Nissan Altima
1,049 Great Deals out of 82,898 listings starting at $670
Used Hyundai Elantra
664 Great Deals out of 51,952 listings starting at $895
Used Honda Accord Coupe
175 Great Deals out of 10,966 listings starting at $1,988
Used Ford Focus
867 Great Deals out of 58,281 listings starting at $800
Used BMW 3 Series
1,501 Great Deals out of 38,748 listings starting at $1,495
Used Nissan Sentra
624 Great Deals out of 52,377 listings starting at $2,000
Used Ford Mustang
549 Great Deals out of 42,541 listings starting at $1,699
Used Volkswagen Jetta
510 Great Deals out of 31,465 listings starting at $1,000

Used Cars For Sale

2017 Honda Civic EX For Sale
9,615 listings starting at $18,611
2016 Honda Civic EX For Sale
11 Great Deals out of 1,311 listings starting at $16,724
2015 Honda Civic EX For Sale
35 Great Deals out of 644 listings starting at $12,995
2014 Honda Civic EX For Sale
31 Great Deals out of 658 listings starting at $10,440
2013 Honda Civic EX For Sale
60 Great Deals out of 1,193 listings starting at $8,990