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 > General Smog Check > Question

Jeep Cherokee Emission Monitors Not Ready

I spent $995.00 on replacing my Jeep Cherokee's catalytic converter. The SUV runs fine and emissions are now very low. The smog technician however will not complete the smog test because he says the emission monitors are not complete. I don't know what to do. I though having spent almost a thousand dollars would have gotten me a guaranteed pass! What can I do? Thank you.
Answer:

Jeep Cherokee Drive Cycle

Since having replaced your Cherokee's catalytic converter and clearing any trouble codes, your SUV's emission monitors were cleared as well, in other words, the emission monitors (also known as readiness flags) were erased, and now need to be completed again. In order to make the monitors READY or COMPLETE you'll need to drive your Jeep Cherokee in a specific drive pattern, known as a Jeep Cherokee Drive Cycle. Typically driving 200-300 miles over the course of a week and in both city and highway traffic is enough to complete the monitors. Sometimes however the driving pattern required is not met by regular driving, and the specific segments of the entire Drive Cycle must be performed individually.

Be very careful performing the drive cycle on public roadways. There are many starts and stops, as well as varying driving speeds. Smog check repair stations suggest performing drive cycles using dynomometers. If you feel you may be unable to perform the drive cycle safely seek assistance from a Jeep dealership service center or smog check repair station.

During all sections of the drive trace make sure your gas tank is between 1/4 to 3/4 full of gas; never below or above the 1/4-3/4 marks.

Catalyst Monitor Drive Trace

Pre-Conditioning Requirements:

- MIL must be off.

- No DTCs present.

- Fuel level is between 15% and 85% full.

- ECT above 70º F.

- Engine must have run at least 90 seconds

- Engine between 1,350 & 1,900 rpm.

Driving Procedure

1) Idle vehicle for five minutes (to reach normal engine operating temperature and closed loop operation).

2) Drive with a steady vehicle speed between 30 & 45 mph for 2 minutes.

EGR System Monitor Drive Trace - Vacuum controlled

Pre-Conditioning Requirements:

- MIL must be off.

Driving Procedure

1) Idle vehicle for five minutes (to reach normal engine operating temperature and closed loop operation).

2) Drive with a steady vehicle speed between 40 & 60 mph for 8 minutes.

EGR System Monitor Drive Trace - Electronic

Pre-Conditioning Requirements:

- MIL must be off.

- MAP must be between 0-60 KPa.

- Engine speed between 500-850 rpm.

- ECT is above 180º F (90º C).

- No misfire pending or matured fault should be present.

- A/C clutch, PS Switch and Cooling fans do not change state (turn off).

Driving Procedure

1) Idle vehicle for five (5) minutes (to reach normal engine temps and get in to closed loop operation).

2) Drive with a steady vehicle speed between 40 & 60 mph for 2 minutes.

3) Idle vehicle for three (3) minutes.

Evaporative System Monitor Drive Trace

Trace 1: Standard Type

Pre-Conditioning Requirements:

- MIL must be off.

- No Evaporative DTCs present.

- Fuel level is between ½ and full.

(Note: monitor may still run with tank fill between 15% and 85%).

Driving Procedure

1) Idle vehicle for five minutes (to reach closed loop operation).

2) Drive with a steady vehicle speed between 30 and 45 mph for 2 minutes.

Trace 2: Leak Detection Pump

Pre-Conditioning Requirements:

- MIL must be off.

- No Evaporative DTCs present.

- Fuel level is between 30 & 85 % full.

Driving Procedure

1) Cold soak vehicle, start and idle vehicle for 4 minutes.

2) Drive in-town (stop and go) for 5 minutes, using smooth acceleration and deceleration.

3) Stop and idle vehicle for 4 minutes.

O2 Sensor Monitor Drive Trace

Pre-Conditioning Requirements:

- MIL must be off.

Driving Procedure

1) Idle vehicle for five minutes (to reach closed loop operation).

2) Drive with a steady vehicle speed above 25 mph for 2 minutes.

3) Stop and idle for 30 seconds.

4) Smoothly accelerate to a speed between 30 and 40 mph.

5) Repeat steps 3 & 4 five (5) times.

O2 Sensor Heater Monitor Drive Trace

Pre-Conditioning Requirements:

- MIL must be off.

Driving Procedure

1) Idle vehicle for five minutes (to reach closed loop operation).

2) Shut engine off and leave vehicle off for ten minutes.


posted by SmogTips Support

 

View SmogTips.com in: Desktop / Mobile