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P0130 Code – GM

Oxygen Sensor Circuit Malfunction - Bank 1, Sensor 1

What it Means: OBD-II code P0130 represents a problem with an O2 sensor on your GM.

The oxygen sensor produces voltages according to the oxygen levels in your car’s exhaust. This voltage will vary between .1 and .9 volts. .1 indicates lean and .9 indicates rich. Your vehicle’s ECM monitors the voltage output of the O2 sensors while in a closed loop so it can determine how much fuel needs to be injected into the engine. 

Pontiac engine

A Pontiac Sunbird 2.0 L SOHC I4 engine via VX1NG

If the O2 sensor voltage is reading too low for an extended period of time, the code P0130 is triggered. The usual suspects include:

  • Water corrosion in the connections
  • Loose terminals at the connections
  • Burnt wiring
  • Short in the wiring from rubbing on exhaust and engine components
  • Holes in the exhaust pipe
  • Vacuum leak at the engine
  • Bad O2 sensor
  • Bad ECM

If the problem appears to be indicative of codes that come and go, it is likely an issue with the connections or the wiring . To check this, use a voltage meter and wiggle the wires to see if the voltage increases. If it does, that means there's a short.

If there are no signs of a short existing, a visual inspection should begin. This involves looking for holes and leaks in the exhaust, testing for vacuum leaks, and replacing the O2 sensor. In very rare cases, the ECM might be bad.

If you have addressed every other possible cause and nothing comes up, then it might be time to suspect the ECM. Other signs of a bad ECM include poor performance, failure to start, and erratic shifting in automatic transmission.

NOTE: Every effort has been made to provide accurate advice in this write-up, but you should consult a professional mechanic before making major repairs or replacements. This guide is meant to explain the possible causes of trouble code P0130, but it is not meant to act as a definitive troubleshooting or repair guide.