P0141 is a very common OBDII code that occurs in the GMC Sierra. It is caused by a failure in one of the elements that heat the oxygen sensors, specifically bank 1 sensor 2, which is downstream from the catalytic converter. It technically stands for:
The purpose of the heated element in the oxygen sensor is to quickly bring it up to normal operating temperature after your Sierra has been started.
Related: P0135 GMC Sierra
GMC Sierra P0141 Symptoms
Typically, the only symptom of P0141 is going to be the service engine soon light. It should not be considered a breakdown risk. But, like anything that causes the service engine soon light to come on it is a good idea to have it fixed as soon as possible.
P0141 Causes: GMC Sierra
Here are the most common issues that cause the P0141 code in the GMC Sierra. They are presented in order (somewhat) of most to least likely to cause the problem.
- Bad Oxygen Sensor– The oxygen sensor itself is one of the most likely reasons that P0141 is triggering your service engine soon light. Although it is a temptation to replace it right away, it wouldn’t hurt to check out the wiring harness around it before hand. See directly below.
- Wiring Harness Damage– The wiring that goes to the front and rear oxygen sensors is very susceptible to damage. This is due to the fact that O2 sensors are under the chassis where they are subject to punishment from road debris, and they are subjected to a lot of exhaust heat. The downstream sensor is espescially susceptible to this problem Here’s how to find a short in the wiring harness (Youtube)
- Damage to the Terminal– The terminal that the oxygen sensor connects to (the plug) is also relatively susceptible to damage. You’ll want to make sure that there is voltage going to it. There’s more on that directly below.
- Blown Heater Sensor Circuit Fuse– Here’s how to test if a fuse is blown (Youtube).
- Wrong O2 Sensor– If you are getting P0141 after having recently replaced your Oxygen sensor, it may be that the replacement is wrong or bad.
Sierra P0141 Diagnosis
Here is a fantastic video that covers all aspects of diagnosing a P0141 trouble code.
It is possible to diagnose the P0141 with a multimeter. If you use the multimeter, you’ll know whether or not the voltage coming to and from the oxygen sensor is within spec, this can help you determine if it’s your Sierra s O2 sensor, or wiring harness that’s the issue.
If you don’t have access to a multimeter, it certainly wouldn’t hurt to check the wiring to between the fuse box and the Oxygen sensor first. If it ends up being a wiring issue, it’ll save you money over buying an unnecessary O2 sensor.
You can also use a voltage test light to determine whether or not the oxygen sensor is getting any voltage at all (they’re about $5 at Walmart). If it’s not getting any voltage, attache the test light to the harness plug and shake the wiring a little bit. If the light comes on, even for a second, you know that you have a short circuit causing the P0141 trouble code.
Bank 1 Circuit 2 is located BEFORE the catalytic converter in the exhaust flow sequence.
Most of the time with P0141, it’s going to be the oxygen sensor itself that has caused the code to trigger. Good luck finding whatever caused it in your GMC Sierra. If you have anything that you would like to add, please feel free to leave a comment below.