Best Answer

Pull the codes from the computer, match the code to the troubleshooting procedure, follow the procedure to find the source. Repair the source, light will go out if that was the only problem. There are "monitors" or self test the computer runs the car through, if a problem occurs, it may not run all of the self tests until that problem is taken care. Therefore, another problem may exist. It is emission related.

User Avatar

Wiki User

โˆ™ 2005-02-03 22:43:03
This answer is:
User Avatar

Add your answer:

Earn +5 pts
Q: Why would your Check Engine Light come back on even though you have replaced the O2 sensor and cleared the code?
Write your answer...

Related Questions

Why wont your speedometer work on your peugeot 306 even though you have replaced it?

you replaced speedo, so try replacing speed sensor

99 Pontiac grand am 6-cylinder starts then stalls when it starts the idel will go up and down then a day later it will start and run great when it runs bad engine light on?

Have the code read. Autozone will do this for free. Even though the light is not on now. It will be stored as a recent code. It has to cleared to be erased completely. Good luck. i had the same problem with mine it turned out to be the knock sensor i replaced it and the problem went away give that a try

Renault laguna engine turns over but wont start no spark?

When this happened to me on my seven year old 2.2 DCi laguna I had to hae taken in to the Renault dealers. It turned out to be the a problem with both the cam sensor and the fuel injection sensor. Both had to be replaced at a cost 0f £300 in all. It did cure it though! May also be TDC / crank sensor. Worth removing it and giving it a clean.

Where is the crankshaft position sensor on a Honda?

Depending on the year it could be in the distributor or by the crank's pulley. On 93-98 Honda passports with the 3.2l engine the crankshaft position sensor in located on the passenger side of the engine near the engine mount. 93-95s did not have the camshaft sensor though. that was added in 96 and is located on the d/s valve cover in the outside upper corner

The maf was replaced but check engine light is still on?

You need to reset the light by using diagnostic equipment even though the part was replaced the fault code will still be stored in the ECU memory.

1999 jeep sahara change both oxygen sensors engine light still coming on with rear flank on the computer?

I dont know what codes you were getting. double check the connections. And get the code cleared. retry it. If it still comes on reread the code to see what it says. You didnt get anything on tips of the o2 sensor did you? Another thing the rear one refers to the one after the Cat converter. Is that the one that was replaced? People sometimes forget this. If there is still a probplem the circuit has a prblem. The code would be saying this though. Hope this helps.

How do you change a oxygen sensor in a 1991 Oldsmobile cutlass supreme?

The O2 sensor is located on the rear exhaust- driver's side. Easiest to get to if you rotate the engine forward and away from the firewall. I have used regular wrenches even though they sell O2 sensor wrenches.

How to replace the knock sensor on my Zafira?

Unscrew the bolt through the centre of the sensor & unplug the wiring connector. Re-fitting is the reverse of removal. More often than not the knock sensor is not faulty though, the engine is knocking due to low oil level.

Just had a gasket replaced in my engine and all of a sudden white smoke is coming from my engine and I am loosing engine coolant no burning smell though what could it be?

Sounds like head gasket is leaking allowing coolant into combustion chamber

Water temp light is coming on even when needle is not past it just replaced thermostat engine block and radiator on the edge at the moment?

On our '92 the light comes on when the water level in the resovor is low. If you have the correct level of coolent possibly your sensor could be bad. Try filling the plastic resevior if it is low. There is a sensor on top of it that makes the light come on even though the temp is not hi.

Why does your 1996 corsica 3.1 idle super high replaced throttle pos sensor still does it has great vacuum?

It wouldn't make much of a vacuum leak to cause the engine to idle at high RPM. First check for vacuum leaks even though you may still have good manifold vacuum.

89 Pontiac 6000 cooling fan will not come on even though I replaced the temp sensor and everything else looks okay. Fan works when the air is turned on and the temp sensor is unplugged What's next?

Which sensors have you replaced, these cars have 2 of them. One located on the thermostat housing, and one located on the rear of the block under the exhaust manifold.

What causes heat light to stay on?

A faulty temperature sensor can cause the ECm to think your engine is overheating, this turning the heat light on constantly. You should make sure that your engine isn't in fact overheating though.

Do you need to replace oil and filter a month later after replacing the head gasket on a diesel van even though it was done when the gasket was replaced?

It would be recommended if coolant had mixed with the engine oil before the head gasket was replaced.

98 contour svt has p0340 code even though replaced the cam sensor and tested wiring back to pcm but still got prob can you help?

had similar prob i had to replace # 4 cylinder and my entire cam pack on my engine...obd reader are sweet to have ..get one made for any vehicle.they are $$$, but saved me 780.00

Can an O2 sensor tps throttle switch prevent a car from starting?

I have a magna Executive with a o2 sensor. I have been having problems with ever since I had to replace the main computer under the dash. I keep getting chech engine wring lights on my dash. Since then I have had the engine checked and the o2 sensor repalced only thave to problem come back to me again and again and going back to the dealer. So I disconnected the sensor from the engine to the computer and the engine still starts and I get excelleration and the car runs, though it does run sluggish and feels fuel strvations is there, but yes you can run the car without the o2 sensor especially in a Magna TR....

What if 2003 Yukon keeps getting PO171 and PO174 codes Unlikely both or all 4 oxy sensors are bad?

Have you had your 4 oxygen sensors replaced? It turns out when they replaced my oxygen sensors, they were after market parts so the service engine light did not come and gave codes even though they were replaced.

What a camshaft sensor does?

cheap back up to crank sensor. it may allow the car to run with out crank sensor, though poorly

Can we be replaced and are being replaced by robots?

we can i don't know if we are though.... its hard to answer..... we will just have to wait and see.

What causes the low coolant light to come on a 1997 mercury cougar xr7 even though the reservoir is filled correctly?

When the low coolant warning light comes on and the car has enough coolant, it usually means there is a problem with the coolant level sensor system. The sensor may need to be replaced.

What does the diagnostic code P0320 mean for a 2001 Jeep Cherokee?

P0320 (M) No Crank Reference Signal at PCM No reference signal (crankshaft position sensor) detected during engine cranking.P0320 (M) No RPM Signal to PCM (Crankshaft Position Sensor Signal to JTEC) A CKP signal has not been detected at the PCM.The Sensor has failed. Replace the *Cam Position* Sensor in the Distributor.***added by DrStoooopid You're half right. The sensor has failed, but there's two of them.1. Cam position sensor, which is on the front of the engine. (location varies depending on engine)and is most definitely not in the distributor. There IS no distributor in those engines, they're electronically controlled. The cam position sensor sits .30" from one of the camshafts.2. CRANK position sesnor which that code is referencing. The CRANK position sensor is the one that failed. (They usually fail in pairs though). The crank position sensor is harder to get to. It's on the back of the engine, near the transfer case.

What could cause a '98 Ford Contour to stall even though it does not run rough restarts easily but has a 'Bad O2 Sensor' engine code?

When there is a code in the computer the engine runs on a set of specs and is not variable. Get the 02 fixed.

Was there guillotine in the Tower of London?

yes it was replaced by a monument though

What is the 3.3l crank position sensor location for a Dodge Grand Caravan?

In the 2002 Dodge caravan with a 3.3 liter engine where the 8th digit of the vin is a 3 the crankshaft position sensor is located on the top right side of the transmission bellhousing. If you are looking into the engine compartment on the Driver's side place your head directly to the right of the ignition coils and look down at the bellhousing of the transmission. You will see the sensor there though it is slightly hidden by the exhaust crossover pipe.

How can you tell if the knock sensor is bad or not in a 1996 Nissan Maxima?

ohm it out at the connector on the right side of the engine. if it is no continuity it is bad. it has very high ohms though so you need a good meter.