2001 PT Cruiser 2.4L upstream O2 sensor issue

Asked by Eric Dec 11, 2018 at 03:19 PM about the 2001 Chrysler PT Cruiser Limited Wagon FWD

Question type: Maintenance & Repair

My 2001 PT Cruiser (2.4L with manual transmission) was throwing codes of
a bad O2 sensor heater on the upstream sensor.  I replaced both sensors
(upstream and downstream) with new Bosch sensors from Advance Auto
Parts.

Now I'm getting a new code showing PO134 "O2 sensor circuit no activity
detected (Bank 1, Sensor 1)".  Scan tool shows the O2 sensor voltage
fluctuating between 0.48V and 1.28V.  Online sources claim the sensor
should not register a voltage above 1.0V (super rich) or below 0.1V (super
lean).

I replaced the O2 sensor with an identical one and got the same error.  I'm
starting to suspect it doesn't like the Bosch sensor even though it's the
correct part number.  A friend tells me Chryslers are very particular about
accepting non-OEM parts.

Anyone got any experience with this issue?

65,590

firebird338 answered 6 years ago

Had same problem with my vehicle replaced 02 sensors and same code came back up found out 87 octane gas was causing it to come on started using 92 and 93 octane gas took about 10 tank fulls of the high octane gas and check engine light coming and going off 4 times but it finally went out and stayed out. If you need it to go out sooner you can try cleaning the converter with something like cataclean that cleans converters read some reviews about it most of them was positive as far as getting check engine light to go out.

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Eric answered 6 years ago

I'm not sure that will help. The code is for the *upstream* O2 sensor which is ahead of the catalytic converter, therefore it's unaffected by anything *downstream*...such as the catalytic converter.

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