1. Home
  2. General Toyota Forum
  3. 1991 Camry LE V6- 2.5L DOHC (2VZ-FE) O2 Sensor Problems

1991 Camry LE V6- 2.5L DOHC (2VZ-FE) O2 Sensor Problems

My Camry has 63,650 miles driven and it failed NYState Emissions inspection at a Long Island gas station on Thursday. Due to history of this vehicle, I decided to bring it to a Toyota dealership for diagnosis for the cause of the following emission results:

Vehicle Readings: HC 1.29 gpm CO 31.89 gpm NOx 0.09 gpm Test Limits: HC 0.80 CO 15.00 NOx 2.00

The dealership found (today, 2 JUN 2006) no stored fault codes in onboard computer. Dealer stated that they: " found O2 sensor not fluctuating as designed. O2 sensor stays at 0.68 volts. Resistance above specs, 12 ohms. O2 sensor should be replaced. "

Dealership installed an O2 sensor that they later determined to be faulty (Shorted). The original O2 sensor was reinstalled in the vehicle.

My present concern while another O2 sensor is on order is that the "CHECK" light on dashboard remains lighted. Dealership attempted to reset the onboard computer but was not successful; the CHECK light lights again.

Question 1: If car is driven as is, is there a possibility of causing damage to engine OR to the onboard computer ? Should I avoid driving this vehicle?

Question 2: Is it possible/probable by installing a shorted O2 sensor, that the onboard computer was permanently damaged ?

Repair History: EGR and CAT replaced in year 2004. Engine Tune Up (PLUGS, Air Filter, PCV Valve) in year 2005.

Thanks for your information. ~ Vince ~

Reply to
Vince
Loading thread data ...

Driving the car for a week with the check engine light should not cause damage to the engine or the onboard computer, known as an electronic control unit, or ECU.

Possible - yes, probable - no.

Reply to
Ray O

Thanks foer your info reply, Ray.

You mention "for a week ... " During the time that this car with CHECK light lighted is driven, should I expect poor performance, poor gas mileage, or some other driveability symptom ?

To be clearer, the light shows the word " CHECK ", as opposed to showing the words "CHECK ENGINE".

This vehicle is driven less than 4,000 miles annually.

Many years ago, at approximately 33.350 driven miles, the CHECK ENGINE was shown. I don't recall now if this was a Light or a drop down icon. This happened while I was visiting in Michigan. A Toyota dealership found no stored codes, and said it might be an O2 sensor and that gas mileage might be poor on my return trip to New York. During the drive home, the CHECK ENGINE disappeared. The vehicle passed NYState emissions each and every year until reaching approximately 50,000 driven miles.

~ Vince ~

Reply to
Vince

You're welcome!

The car will experience poorer performance and poorer gas mileage, but I doubt if you will be able to tell the difference. If the original O2 sensor is re-installed, the performance and fuel mileage will probably be the same as what you had at the time you first brought the car in. Worst case, you'll get 10 to 15% worse gas mileage.

The common term for the light with the engine-shaped icon and the words "check" inside the icon is "check engine light".

Most of the systems monitored by the electronic control unit (ECU) are related to emissions control. The things that affect emissions control, like the ratio of air to fuel, also affect fuel mileage and engine performance.

Some systems have 2-trip detection logic, where a fault must be present during 2 trips before the check engine light is illuminated. There are defined parameters for a "trip" so a trip to the corner store might not count as a trip and so it might take longer before the check engine light comes on.

The low usage on your car can cause a different set of problems than what cars that get more use experience. As gasoline deteriorates, it forms varnish deposits in the fuel system, injectors, and inside the intake system. The varnish can gum up injectors so they do not have a nice spray pattern so the fuel will burn properly.

Moisture can condense in the fuel system, causing drivability problems.

If you park the car for long periods of time, keep the fuel tank as full as possible.

An exhaust system that undergoes only short trips will tend to rust more quickly because the moisture present in exhaust gases at startup do not get dried out of the exhaust system.

A battery that sits for long periods of time can become sulfated and lose its ability to hold a charge.

Reply to
Ray O

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.