1999 Chevrolet Malibu LS 3.1 P1133 code problem
Thread Starter
CF Beginner
Joined: Jun 2019
Posts: 2
Likes: 0
From: Franklinton, NC
1999 Chevrolet Malibu LS 3.1 P1133 code problem
I have a 1999 Chevrolet Malibu LS 3.1 ( 4 door ) that P1133 HO2S B1-S1 insufficient Switching continuously comes back on. I have replaced these parts which I'm listing with the original AC/Delco parts. Both upstream & downstream O2 Sensors--3 times, New wiring harness for the upstream O2 Sensor, EGR Valve & Gasket, New Air Pump with new Diverter valve. Have completed a smoke test to check for vacuum leaks nothing found. Every shop that I take this car to can't find anything to cause this code to keep coming up. Need help to solve this problem
CF Monarch
Joined: Oct 2017
Posts: 4,605
Likes: 268
From: USA
I have a 1999 Chevrolet Malibu LS 3.1 ( 4 door ) that P1133 HO2S B1-S1 insufficient Switching continuously comes back on. I have replaced these parts which I'm listing with the original AC/Delco parts. Both upstream & downstream O2 Sensors--3 times, New wiring harness for the upstream O2 Sensor, EGR Valve & Gasket, New Air Pump with new Diverter valve. Have completed a smoke test to check for vacuum leaks nothing found. Every shop that I take this car to can't find anything to cause this code to keep coming up. Need help to solve this problem
Thread Starter
CF Beginner
Joined: Jun 2019
Posts: 2
Likes: 0
From: Franklinton, NC
Thank You for answering my post that what I was thinking also. I forgot to mention that I have replaced the complete fuel pump assembly / fuel filter / last December 2018 due to fuel gauge inside vehicle stopped registering. I just replaced the MAP Sensor also this past Saturday due to being the original factory sensor that came on the car, I also cleaned the MAF Sensor this past weekend. I will have the fuel pressure checked along with checking the fuel injectors. Thank You can for your reply have a very nice day Greg
CF Monarch
Joined: Oct 2017
Posts: 4,605
Likes: 268
From: USA
Thank You for answering my post that what I was thinking also. I forgot to mention that I have replaced the complete fuel pump assembly / fuel filter / last December 2018 due to fuel gauge inside vehicle stopped registering. I just replaced the MAP Sensor also this past Saturday due to being the original factory sensor that came on the car, I also cleaned the MAF Sensor this past weekend. I will have the fuel pressure checked along with checking the fuel injectors. Thank You can for your reply have a very nice day Greg
CF Beginner
Joined: Jun 2019
Posts: 1
Likes: 0
1. Verify the O2 heater is working by turning the key on engine off. The O2 reading should start at about 450 MV and after 90 seconds it should read low, as there is a lot of oxygen in the exhaust system without the engine running.
2. If it did not change, verify good power on the Brown wire and good ground on the Black wire.
3. With the Oxygen sensor electrically disconnected, ground the Purple wire coming from the ECM. The scanner should show just about 0 volts. Add a ground to the Tan wire and see if it works better.
4. If the scan tool shows ECM responding properly to O2 circuit being grounded, replace the sensor. Even though it's new it could be the wrong part number, it's happened to me many times. If it doesn't respond, it's the ECM.
2. If it did not change, verify good power on the Brown wire and good ground on the Black wire.
3. With the Oxygen sensor electrically disconnected, ground the Purple wire coming from the ECM. The scanner should show just about 0 volts. Add a ground to the Tan wire and see if it works better.
4. If the scan tool shows ECM responding properly to O2 circuit being grounded, replace the sensor. Even though it's new it could be the wrong part number, it's happened to me many times. If it doesn't respond, it's the ECM.