o2 sensor engine code p0138

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Apr 17, 2013 | 06:18 PM

woodgrain

Thread Starter

Newbie

Joined: Jan 2013

Posts: 11

Likes: 0

From: BC canada

Year: 1999

Model: Cherokee

Engine: 4.0L

o2 sensor engine code p0138

so the obd II reader read "o2 circuit high voltage (bank 1, sensor 2)" . all the research i did said it was the o2 sensor after the cat. so i replaced it. check light never went off after 3 weeks so i plugged the obd II back in. same code came up and i tried to erase it but the check light wont go off and same code plus another "p1491 radiator fan relay control circuit" is still there. any help on either of these problems would be awsome

thanks...xj4life

Apr 17, 2013 | 07:06 PM

tjwalker

CF Veteran

Joined: Nov 2010

Posts: 5,841

Likes: 117

From: In the middle of Minnesota!

Year: 1999

Model: Cherokee

Engine: 4.0

1. Inspect every inch of wiring for that downstream oxygen sensor for the P0138.

2. Here is a link to more information on the P1491.

http://www.justanswer.com/jeep/1v3d9...ced-relay.html