Service engine light, EGR valve flow and bak 1 O2 sensor error

Tiny
BARB123
  • MEMBER
  • 2000 PONTIAC BONNEVILLE
  • 6 CYL
  • AUTOMATIC
  • 185,000 MILES
2000 Pontiac bonneville SSEI with 185000 miles. About 3 weeks ago I started getting an intermittent service engine lgt. Scanned at auto parts store. I was told I might need to clean the egr valve. The egr valve was replaced a week ago and after about 15 miles of driving the light came back on again and stayed on. Before the egr valve was replaced I had noticed a drop in my gas mileage a couple of weeks before the service engine lgt had started coming on. After the egr valve was replaced, I got another scan done, now I have 2 codes (p0401, p1133) low egr flow and bank 1 o2 error. Gas mileage is still bad. One year since spark plugs and fuel filter replaced. What do I check next? What could be the problem?
Tuesday, March 15th, 2011 AT 7:56 PM

3 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
401 is innadequate egr flow, was the port cleaned out while the egr was off? If yes, the position sensor needs to be replaced, if not clean port right thru.
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Tuesday, March 15th, 2011 AT 8:17 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
P1133 is either the bank 1 sensor 1 o2 sensor sluggish, or the A/C pressure sensor high voltage, you need a scantool to watch the o2 voltage switching. It should keep switching from high to low continuosly graph will have many waves.
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Tuesday, March 15th, 2011 AT 8:20 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Also on the p0401 it's easier to clean the port if you remove the throttle body. If this does not fix it, make sure the exhast port from exhuast system is clear, no exhuast pressure= no exhaust flow!
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Tuesday, March 15th, 2011 AT 8:41 PM

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