SureTrack Real Fix – Not Ready

In newer vehicles, the computer monitors the emissions system to make sure there are no faults. If the monitors don’t function as expected, you will have trouble passing an emissions test, and you might replace components that aren’t bad trying to fix it. SureTrack community member goldengate2 had a Nissan Altima in their shop where the owners had replaced the oxygen sensors and the monitor for that system would not set. They posed the question to the community, and with the help of fellow community member just-me and others, they were able to resolve the issue.

The following Real Fix summarizes the interaction between them in the community that led to the solution.

Vehicle
2005 Nissan Altima SE-R 3.5L

Title
Oxygen sensor monitor not ready, replace PCM.

Complaint
Oxygen sensor monitor not ready.

Diagnostic Steps Performed/Parts Replaced
Customer replaced both upstream sensors (new Bosch). Performed a drive cycle and drove it for over 100 miles. For the past few days following drive cycle, driven at 56 mph, the monitor is still not ready. While driving checked data stream and found downstream sensors OK, switching from rich to lean. And both upstream ratio sensor bank 1 stays at .300 to .350 mv. Bank 2 sensor stays between .550 to .650 mv.
Besides the drive cycle is there another way to find out why is not running this monitor?

Best Answer from Community Member just-me
I remember Nissan had some pretty long detailed drive cycles and if they weren’t followed would not run. That being said, I had one that the PCM was bad causing no other concern but O2 monitor would not complete.

Cause
After checking temperature and connection to sensors and PCM I decided to replaced PCM.

Correction
Replaced PCM and then after driving for 15 miles oxygen sensor monitor became ready. Thanks for your help!!