1999 Chevy K1500 throwing 3 similiar codes:p0134,p0154 & p0155

[Keeta]

My 1999 Chevrolet K1500 keeps throwing the same three codes.
1. P0134 Bank 1 Sensor 1
2. P0154 Bank 2 Sensor 1
3. P0155 Bank 2 Sensor 1
Can anyone please help, is the problem the ECM? I find it hard to believe multiple O2 Sensors failed at the same time. If anyone has a explanation I would appreciate some direction/explanation on how to fix this issue. I was getting 400 miles to a tank of gas, now I am getting 200 if I'm lucky.

• 5.0L (305)
• 106,000 miles
• excellent condition
• extremely clean in/out

[Conlan Rose]

If gas mileage has also gone down that bad it might be the o2 sensors.

[PantheraUncia]

I can't say what the coincidence is that they all fail at the same time. You have 2 things to look at from your post. 1. The age of your truck and 2. the mileage.

I have 3 O2 sensors in my truck also. Left and Right near the cats and then one before the muffler. One of mine had failed and my truck is 1 year newer than yours, but I had 150,000 miles on it when the 1 O2 sensor failed. They basically get dirty, used, etc.

Most people will tell you to just replace the ones that fail. I decided that I wanted brand new sensors all the way around so I went ahead and bought 3 of them anyway. They were about $45 each at Advance Auto, Auto Zone, Pep Boys, Car Quest, Napa, or o'reilly auto parts.

I would get an O2 Sensor socket though, because they have a cable on them that a normal socket will not get around and the socket wrench will make it easier to remove than a crescent wrench.

[Big_Mike]

My 1999 Chevrolet K1500 keeps throwing the same three codes.

Keeta, I had a similar problem with my Silverado ('93) because it kept "throwing" a check engine light, so I took it to a shop and had a mechanic hook up a scan tool to it. It was an O2 sensor code and I was told to check the wiring and the connector for the sensor (bad connection, worn wiring insulation, etc.) I did and everything looked fine so I installed the new sensor. Currently I'm not driving my Silverado (due to other repairs being made), but I hope this will resolve the problem. It would be odd for three sensors to fail at the same time... But it's possible.

Just to clear something up, have you ever had engine problems before? For example, I've heard a mechanic recommend changing out 02 sensors if a head gasket ever blows, due to coolant entering the exhaust and possibly contaminating the 02 sensors (depending on how long it was driven in that state). Hope that helps...

[Keeta]

Keeta, I had a similar problem with my Silverado ('93) because it kept "throwing" a check engine light, so I took it to a shop and had a mechanic hook up a scan tool to it. It was an O2 sensor code and I was told to check the wiring and the connector for the sensor (bad connection, worn wiring insulation, etc.) I did and everything looked fine so I installed the new sensor. Currently I'm not driving my Silverado (due to other repairs being made), but I hope this will resolve the problem. It would be odd for three sensors to fail at the same time... But it's possible.

Just to clear something up, have you ever had engine problems before? For example, I've heard a mechanic recommend changing out 02 sensors if a head gasket ever blows, due to coolant entering the exhaust and possibly contaminating the 02 sensors (depending on how long it was driven in that state). Hope that helps...

I checked the head gasket and all checked out. However, I have a small Manifold leak in the very back, but as long as I don't use a high pressure radiator cap it doesn't drip at all, so I haven't bothered with it. I wonder though if when it was dripping if it could have caused a issue. I guess I will order a o2 sensor and see what happens. Thanks for your response.

[Big_Mike]

Thanks for your response.

You're welcome. Glad to have suggested something useful to you. At least you found a possible cause. Hope you get everything fixed.