Chevy Silverado P0135 – Test your O2 Sensor
The oxygen sensor in your Silverado can foul out over time or even fail all together. When this happens chances are you will see your Chevy Silverado check engine light turn on. For some of the later model trucks this may come across as a message on your instrument cluster. When you need to retrieve your Silverado trouble code, you will need to use a OBDII scan tool to read the codes in your computer. When the stored diagnostic trouble code returns as a Chevy Silverado P0135 trouble code, it shows an issue with your primary oxygen sensor.
The Chevy Silverado P0135 OBDII code translates to Oxygen O2 Sensor Heater Circuit Malfunction. The oxygen sensor in question is for bank 1 and sensor 1, which means the primary O2 sensor located on the side of the engine with the #1 cylinder on it. In your Chevy Silverado, this means that the Bank 1 Sensor 1 O2 sensor is on the ‘driver’ side of the engine and the Bank 2 Sensor 1 is on the ‘passenger’ side.
Today I’ll be showing you how to fix your Chevy Silverado P0135 trouble code in a 2001 truck with the 5.3 liter Vortec engine in it. Because the Chevy Silverado P0135 trouble code is for the driver side of the engine, you may need an automotive jack and jackstands to test the oxygen sensor. In order to test your primary or upstream O2 sensor, you will need a digital multimeter.
Your primary oxygen sensor is what your Chevy Powertrain Control Module uses to dictate and operate your Vortec EFI system. When you have the Chevy Silverado P0135 check engine light, this means there’s a problem with the internal resistance of your oxygen sensor or there’s no power going to your O2 sensor heater element. The primary oxygen sensors must be tested once you have the driver side of your Silverado lifted and safely secured.
Fixing the Chevy Silverado P0135 trouble code
Depending on the model and year of your Chevy Silverado the upstream O2 sensor may be square or a flat style. Our 2001 unit is a flat four pin style sensor, and using the Chevy Silverado O2 sensor wiring diagram below you can test the heater element. The wire you need to address is the PINK one, or the one that leads to PIN D on our wiring schematic.
Once you have the pink wire lined up in your sights go ahead and turn your Silverado ignition to the “ON” position. This should send 12 volts to your primary oxygen sensor heater. You will be testing for this power signal at PIN D and with the ignition turned to ON you should see 12 volts of switched power here. If you do that means that your primary O2 sensor is getting the power it needs.
If you don’t have power at this wire, make sure to check the O2 sensor fuse in your Silverado fuse box. If this fuse is blown then you won’t get power and this is what will cause your Chevy Silverado P0135 check engine code. Although the oxygen sensor is getting power, it’s just half of the equation. The next wire to check is the one leading to PIN C, this is the signal ground wire for your Silverado O2 sensor. This wire is BLACK in color and should return a PCM supplied ground signal.
Have power and ground at these sensors? Then you will need to replace the primary oxygen sensor first. Once you have your Silverado O2 sensor installed properly, you must use a OBDII scan tool to erase your Chevy Silverado P0135 code. Have any questions about the P0135 trouble code? Leave me a message below and let me know!