Smogtips
CHOOSE YOUR CITY OR ZIPCODE:
Within:
SELECT SMOG CHECK TYPE:  

Join the community and post your question. Use our Ask-A-Tech for free now! ASE experts standing by.

Forum > Failed Smog Test > Question

1998 Dodge Ram 1500 Failed Smog Test for Incomplete Monitors

My 1998 Dodge Ram 1500 2 WD. 5.2 engine failed the smog check the first time because of 2 faulty oxygen O2 sensors. I replaced them both and cleared the trouble codes. The codes haven't come back yet but my truck still fails the smog check. When I connect my trouble code scanner and run the test, is shows that the computer has not completed the emissions monitors for the Oxygen Sensors. I was wondering if this have something to do with the catalyst converter.


Answer:

While clearing your Dodge Ram's oxygen sensor trouble codes you also erased all of the emission monitors, including the Oxygen Sensor Monitor. Emission monitors are internal self tests which your Dodge conducts to ensure its emission systems are working properly.

In order to set the emissions monitors (also known as readiness flags) you'll need to drive your truck approximately 100-200 miles in order for the ECU to complete the self-tests and set the Monitors. The following is a Generic Drive Cycle.

Begin by: (Make sure you have between 1/4 and 3/4 fuel in the gas tank. The EVAP test will not run while your Dodge Ram has a full tank of gas or the gas tank is near empty).

- Start the engine. Idle the engine in drive for two and a half minutes with the A/C and rear defroster on.

- Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle.

- Hold at a steady speed of 55 mph for three minutes.

- Decelerate (coast down) to 20 mph without braking.

- Accelerate back to 55 to 60 mph at ¾ throttle.

- Hold at a steady speed of 55 to 60 mph for five minutes.

- Decelerate (coast down) to a stop without braking.

If all other emissions systems are functioning properly, completing the drive cycle above should set the oxygen sensor monitor required to pass the smog check. It will not hurt to perform the drive cycle 2 or 3 times before the smog inspection. Take caution when performing drive cycles on public roadways.


posted by SmogTips Support

 

View SmogTips.com in: Desktop / Mobile