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2013 Infiniti G37 — catalyst efficiency code but car drives normally

RustBeltDetailer958Community StarterJul 5, 20262013 Infiniti G37 xSSalt Lake City
2013 Infiniti G37 xS, about 165,000 miles. A catalyst efficiency code came back after clearing once. The car drives normally and there are no misfire codes. Before condemning the catalytic converter, what sensor/data checks are worth doing? Mostly looking for the right next step.
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23 replies

TrackCommuter97Community StarterCommunity StarterJul 5, 2026permalink
Log the conditions before you spend. Write temp, speed, and in-gear vs coast when the 2013 Infiniti G37 does it — then decide on parts. That's the branch I'd chase this week. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. I'd want a dollar figure or a measured spec, not 'should be fine.' Checking again after work.
RustBeltLearnerCommunity StarterCommunity StarterJul 5, 2026permalink
This is usually cheaper to test than to guess. Write temp, speed, and in-gear vs coast when the 2013 Infiniti G37 does it — then decide on parts. You'll know quickly if you're on the wrong tree. Post the numbers (or the code) and people can get more specific. Make the next action something you can finish this week. I refuse to clear codes until someone else sees them.
TowDaily63Community StarterCommunity StarterJul 5, 2026permalink
This is usually cheaper to test than to guess. A pressure test beats staring at a dry driveway if the 2013 Infiniti G37 is losing coolant with no puddle. That's the branch I'd chase this week. Just my two cents from doing this recently. This is the version I'd tell a friend.
CanyonEnthusiast939Community StarterCommunity StarterJul 5, 2026permalink
Same neighborhood, different next step: Get a real battery/charging test on the 2013 Infiniti G37, not just resting voltage, before blaming a module. You'll know quickly if you're on the wrong tree. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. Keep sale price, fees, and rate as three different conversations. Might be overthinking it, but I'd rather overthink than overspend.
MarketDriver918Community StarterCommunity StarterJul 7, 2026permalink
Agree — and I'd add this: Write temp, speed, and in-gear vs coast when the 2013 Infiniti G37 does it — then decide on parts. Save the big job until that test fails. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. Write the result down so the next test isn't a repeat of the last one. This is the filter I use when the thread starts repeating itself. Checking again after work.
TowDaily63Community StarterCommunity StarterJul 5, 2026permalink
Start with the test that can prove you wrong. Write temp, speed, and in-gear vs coast when the 2013 Infiniti G37 does it — then decide on parts. Save the big job until that test fails. Take it or leave it — that's what I'd do. If the story changes I'll post the new data.
ColdStartHauler469Community StarterCommunity StarterJul 6, 2026permalink
Agree — and I'd add this: Get a real battery/charging test on the 2013 Infiniti G37, not just resting voltage, before blaming a module. Save the big job until that test fails. Did the worksheet show tax yet? I'd rather be boring and correct. If that fails I'll eat the diagnostic fee.
SunBeltDaily76Community StarterCommunity StarterJul 5, 2026permalink
If it were in my driveway, two 2013 Infiniti G37s can feel identical and have different causes, so measure before you copy someone else's repair. That's the branch I'd chase this week. That's the sequence I'd use. I'd rather be boring and correct. I keep a notes app thread for this now.
BoostSeller448Community StarterCommunity StarterJul 5, 2026permalink
Intermittent stuff lies if you only catch it once. Write temp, speed, and in-gear vs coast when the 2013 Infiniti G37 does it — then decide on parts. Save the big job until that test fails. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. Verbal 'we'll take care of it' is not a plan. I keep a notes app thread for this now.
RustBeltDetailer958Community StarterCommunity StarterJul 5, 2026permalink
OP update: scanned the 2013 Infiniti G37 again and still only have the one pending code, no new lights. That's my plan before I call anyone.
TowDaily63Community StarterCommunity StarterJul 5, 2026permalink
Ask what changed right before it started. Two 2013 Infiniti G37s can feel identical and have different causes, so measure before you copy someone else's repair. That's the branch I'd chase this week. This is from a 2013 Infiniti G37 in Salt Lake City with 165,000 miles. Not gospel, but it saved me a headache. That's coming from doing this as an owner, not a shop. Not interested in a five-hour wait for a shrug.
BoostSeller448Community StarterCommunity StarterJul 6, 2026permalink
Log the conditions before you spend. Write temp, speed, and in-gear vs coast when the 2013 Infiniti G37 does it — then decide on parts. That's the branch I'd chase this week. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. Verbal 'we'll take care of it' is not a plan. Climate here is different, so treat that as a local data point. Checking again after work.
RustBeltLearnerCommunity StarterCommunity StarterJul 7, 2026permalink
I'd push back a little: If a shop can't duplicate it on the 2013 Infiniti G37, bring a video plus freeze-frame data, not just a story. Don't erase codes until someone who can help has seen them. If you share a photo of the worksheet, easier to sanity-check. That's coming from doing this as an owner, not a shop. Cold start is when I can actually reproduce it.
RustBeltDetailer958Community StarterCommunity StarterJul 6, 2026permalink
Cleared nothing. I want service to see the alert on the 2013 Infiniti G37 first. I already checked the easy fluid levels.
HybridDetailer348Community StarterCommunity StarterJul 6, 2026permalink
Intermittent stuff lies if you only catch it once. Capture voltage while the 2013 Infiniti G37 is actually failing — after it restarts you've lost the clue. If the cheap test changes it, stop and reassess. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. Learned this the expensive way on a previous car. Checking again after work.
BoostSeller448Community StarterCommunity StarterJul 6, 2026permalink
Start with the test that can prove you wrong. Two 2013 Infiniti G37s can feel identical and have different causes, so measure before you copy someone else's repair. That's the branch I'd chase this week. I'd want that in writing, not as a promise. Wrote this up on my lunch break.
RoadCamperCommunity StarterCommunity StarterJul 6, 2026permalink
Ask what changed right before it started. Get a real battery/charging test on the 2013 Infiniti G37, not just resting voltage, before blaming a module. That's the branch I'd chase this week. No need to make it theatrical. That's my plan before I call anyone.
GarageDaily128Community StarterCommunity StarterJul 6, 2026permalink
I wouldn't throw parts yet. If a shop can't duplicate it on the 2013 Infiniti G37, bring a video plus freeze-frame data, not just a story. Save the big job until that test fails. That's the whole play. I'll poke at it this weekend.
GarageDaily128Community StarterCommunity StarterJul 6, 2026permalink
I'd want a measurement, not a hunch. Loaded-suspension checks on the 2013 Infiniti G37 catch play that a wheels-hanging inspection misses. Don't erase codes until someone who can help has seen them. Do that first. I keep a notes app thread for this now.
RustBeltLearnerCommunity StarterCommunity StarterJul 6, 2026permalink
I wouldn't throw parts yet. Capture voltage while the 2013 Infiniti G37 is actually failing — after it restarts you've lost the clue. Save the big job until that test fails. This is from a 2013 Infiniti G37 in Salt Lake City with 165,000 miles. Post the numbers (or the code) and people can get more specific. Your commute and mine probably aren't the same, but the test still applies. I keep a notes app thread for this now.
RustBeltDetailer958Community StarterCommunity StarterJul 6, 2026permalink
I went back under the 2013 Infiniti G37 and it only happens after a heat soak, not on a cold start. If the story changes I'll post the new data.
ColdStartHauler469Community StarterCommunity StarterJul 6, 2026permalink
I'd want a measurement, not a hunch. Two 2013 Infiniti G37s can feel identical and have different causes, so measure before you copy someone else's repair. Don't erase codes until someone who can help has seen them. Was this after sitting overnight? This is the version I'd tell a friend.
MarketDriver918Community StarterCommunity StarterJul 6, 2026permalink
I'd want a measurement, not a hunch. A pressure test beats staring at a dry driveway if the 2013 Infiniti G37 is losing coolant with no puddle. That's the branch I'd chase this week. This is from a 2013 Infiniti G37 in Salt Lake City with 165,000 miles. Write the result down so the next test isn't a repeat of the last one. I'd sleep better after that step, even if it finds nothing. I keep a notes app thread for this now.
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