2002 GMC Sonoma P0300 & P0155 codes

2002 GMC SONOMA
89,000 MILES • 4.3L • V6 • 2WD • AUTOMATIC
Avatar
TOMMYB79
  • MEMBER
  • 7 POSTS
svc. engine soon lite came on. scan gave me P0300 code: random misfire, and P0155: ho2s heater performance bank 2 sensor 1.
Replaced o2 sensor, plugs, cap, and rotor.
Problem still persists.
Did a resistance check on all o2 sensors. They are supposed to read between 4 & 7 ohms. Mine read zero.
Aug 19, 2015 at 2:05 PM
Advertisement
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
have a pro diagnose this as it can be anything and hopefully you didn't use BoSCH O2 sensors because they give problems. it may be another sensor and the pro can test the heater circuit which is screwing up in your sensors.
Aug 20, 2015 at 6:09 AM
Avatar
TOMMYB79
  • MEMBER
  • 7 POSTS
Oh, crap. Thanks for the info. Bosch is exactly what they sold me.
Going to test the resistance tomorrow with a new vohm meter ( the one I have is pretty old). If it is not right, going to take it back.
Aug 22, 2015 at 5:07 PM
Advertisement
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
the bosch may read right but it's known that these are a big problem so mechanics stay away from them.
Aug 22, 2015 at 5:23 PM
Avatar
TOMMYB79
  • MEMBER
  • 7 POSTS
In thinking about it, any particular brand you would recommend? Thanks again.
Aug 23, 2015 at 3:51 AM
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
stick with delco/Delphi on these
Aug 23, 2015 at 7:54 AM
Avatar
TOMMYB79
  • MEMBER
  • 7 POSTS
Thank you. I also understand the resistance across the heater wires is supposed to be between 4 & 7 ohms. My old one the the 2 new ones I have used measure 13 - 14. Have I gotten false info?
Aug 23, 2015 at 7:59 AM
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
this shold really be tested with scan tool but here is all we have for resistance. you shold also check fuel pressure which should be 60-66 psi if not in that range either a fuel pump or regulator. see pic.
Image (Click to enlarge)
Attached Media
Aug 23, 2015 at 8:52 AM