eliasbecker7
Oxygen Sensor Heater Failure
Summary of the thread
A 2001 Hyundai Terracan experienced an oxygen sensor heater failure, indicated by a check engine light and increased fuel consumption. The likely cause was suspected to be a defective cable or plug connection. After a visual inspection showed no obvious damage, it was suggested to differentiate between the pre-cat and post-cat sensors, with the pre-cat sensor being more likely to affect fuel consumption. A workshop diagnostic confirmed a faulty connection in the pre-cat sensor circuit, which was repaired, resolving the issue.
Did this summary help you solve your problem?
4 comment(s)
eliasbecker7 (community.author)
Thank you for your reply. I have visually inspected the wiring and connectors, but found no obvious signs of damage or corrosion. Regarding your question, could you clarify how to differentiate between the pre-cat and post-cat sensor? I am not entirely sure which one is the source of the error.
dirkjung7
Alright, if a visual check didn't turn up anything, it's time to get a little more hands-on. Pre-cat (upstream) is before the catalytic converter, closer to the engine; post-cat (downstream) is after the cat. The pre-cat sensor is what the ECU uses to adjust the fuel mixture so that's usually the one that causes increased fuel consumption. If you can't tell, it's probably best to take it to a workshop and have them do a proper sensor testing.
eliasbecker7 (community.author)
I appreciate the detailed explanation and advice. I followed your suggestion and took the Terracan to a workshop. The diagnostic confirmed a faulty connection in the pre-cat sensor circuit. The repair cost 95€. The issue is now resolved. Thank you again for your assistance.
rmh_community_comment_box_header
community_crosslink_scanner_headline
community_crosslink_scanner_intro
community_crosslink_scanner_title
community_crosslink_scanner_price
community_crosslink_rmh_headline
community_crosslink_rmh_intro
community_crosslink_rmh_title
community_crosslink_rmh_subtitle
community_crosslink_rmh_brand
HYUNDAI
community_crosslink_rmh_model
TERRACAN
dirkjung7
Whoa, sounds like a classic O2 sensor heater problem! That malfunction indicator lamp (MIL) staring you down, huh? First things first, have you tried visually inspecting the wiring and connectors going to the O2 sensor? A loose or corroded connection can cause all sorts of havoc. Which O2 sensor is throwing the code – pre-cat or post-cat?