recently my ses light came on and i checked the code and it says p0137b. I read that it is low voltage to one of the o2 sensors, not sure how i can fix the code and hopefully someone on here can give me a little help. I have an 01 gmc sierra with the 5.3. thanks in advance!

 

Start looking for burnt wires. Most likely it's a bad sensor though

• HO2S wire-Sensor pigtail may be in contact with the exhaust manifold or the exhaust system.
• An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provide the supply of oxygen. Inspect the HO2S wires and connections for breaks or contamination. Refer to Heated Oxygen Sensor (HO2S) Wiring Repairs in Diagnostic Aids.
• Inspect for intermittent ground in the signal wire between the connector and the sensor. Refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.
• Lean injectors-Perform the Injector Balance Test. Refer to Fuel Injector Balance Test with Tech 2 or Fuel Injector Balance Test with Special Tool. See: Fuel Delivery and Air Induction\Fuel Injector\Testing and Inspection
• Fuel contamination-Water near the in-tank fuel pump inlet can be delivered to the injectors. The water causes a lean exhaust and can set a DTC. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (W/O Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (W/Special Tool).See: Fuel Delivery and Air Induction\Fuel\Testing and Inspection
• Fuel pressure-System will be lean if fuel pressure is low. Refer to Fuel System Diagnosis. See: Component Tests and General Diagnostics
• Exhaust leaks-An exhaust leak near the HO2S can cause a lean condition. Refer to Exhaust Leakage in Exhaust System.
• Vacuum or crankcase leaks can cause a lean condition.
• If the above are OK, the HO2S may be at fault.

 

Hey thanks for the help! im gonna look into it this weekend ill post what i find.