P0421 code was triggered today while driving. It corresponds to Warm Up Catalyst Efficiency Below Threshold. Within FORScan, its Status mentions "Test Not Complete". Is there a chance the PCM just needs to run through more tests and it might close out the engine light, or not likely? It's been pretty cold this past week not knowing if this could be a factor. I chose not to reset the DTC for this reason and will drive some more to see if it sorts itself.
There actually is a related TSB (01-016/15) for the P0421 code which requires a control logic update for the PCM but my VIN is technically just outside the specified effected VINs within the TSB.
Curious if anyone has experience with a P0421 code on CX5s and can weigh in on possible reasons. We've got a 2016.5 CX-5 2.5L NA model. Below is a screenshot of code freeze frame data from FORScan. Red arrow shows what I'm talking about.
There actually is a related TSB (01-016/15) for the P0421 code which requires a control logic update for the PCM but my VIN is technically just outside the specified effected VINs within the TSB.
Curious if anyone has experience with a P0421 code on CX5s and can weigh in on possible reasons. We've got a 2016.5 CX-5 2.5L NA model. Below is a screenshot of code freeze frame data from FORScan. Red arrow shows what I'm talking about.
Last edited:
