Hint:
Use the table below to help determine the cause of the problem symptom. The potential causes of the symptoms are listed in order of probability in the "suspected area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

Precaution
Problem symptoms table (2006/01- )Catalyst system efficiency below threshold (bank 1)
Monitor description
The ecm uses sensors mounted in front of and behind the three-way catalytic
converter (twc) to
monitor its efficiency.
The first sensor, the air-fuel ratio (a/f) sensor, sends pre-catalyst
information to the ecm. The second
sensor, the heated oxygen (ho2) sensor, se ...
Checking tires
Check if the treadwear indicators
are showing on the tires.
Also check the tires for uneven
wear, such as excessive wear
on one side of the tread.
Check the spare tire condition
and pressure if not rotated.
New tread
Worn tread
Treadwear indicator
The location of treadwear indicators
is show ...
Gcwr, twr and unbraked twr
Confirm that the gross trailer weight, gross combination weight, gross
vehicle weight, gross axle weight and tongue weight are all within the
limits.
Gcwr*
2Wd models: 5985 lb. (2715 Kg)
Awd models: 6100 lb. (2765 Kg)
Twr*
1500 Lb. (680 Kg)
Unbraked twr*
1000 Lb. (450 Kg)
*: ...