Emission system monitors let you know that all systems are functional. Especially before an emissions check. SureTrack community member juniorBACC had a Jeep Compass in the shop that would not set the oxygen sensor monitor even though everything seemed right. They posed the question to the community, and with the help of fellow community member ericsautomotive and others, they were able to resolve the issue quickly.
The following Community Fix summarizes the interaction between members of the community that led to the solution.
2010 Jeep Compass Limited 2.4L
Oxygen sensor readiness monitor won’t set, replaced O2 sensors
Oxygen Readiness Monitor will not set into ready complete. NO check engine light, NO engine performance issues, NO stored or pending codes. NO visual issues to wiring or connectors. All other monitors set and ready except Oxygen sensor monitor.
Diagnostic Steps Performed/Parts Replaced
Went ahead and replaced both upstream and downstream O2 sensors with aftermarket replacements. Replaced PCM with known good PCM and reflashed to newest software calibration. Erased and perform drive cycle, 2 times. Now have over 350 miles on vehicle and all monitors are set except oxygen sensor monitor. Suspected catalytic converter but cat monitor sets and on MODE6 cat monitor test within specification. O2 sensor heater monitor sets as well so not sure what’s hanging up O2 monitor. Checked mode6 and looks like O2 monitor is enabled but test will not complete or monitor will not set in ready condition. Lab scoped O2 signal and found within spec, found O2 sweep was good, sweep time on front sensor was more frequent than the rear sensor. And no pending codes with O2 sensors. Any ideas?
Best Answer from Community Member ericsautomotive
Chrysler is very picky about there O2 sensor readings.
Aftermarket oxygen sensors.
Replaced oxygen sensors with OEM sensors, monitor sets.
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