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P0155 O2 Sensor Heater Circuit Fault - Diagnosis and Fix for 2004 Chevrolet Silverado 2500 HD

Model: 2004 Silverado Fault Code: P0155 Posted: 2015-04-05 12:11

My 2004 Chevrolet Silverado 2500 HD is displaying trouble code P0155, indicating a fault in the B2S1 oxygen sensor heater circuit. I'm looking for step-by-step guidance on how to diagnose and resolve this issue. The B2S1 oxygen sensor is located in the exhaust system and its heater circuit requires proper power and grounding to function correctly. To begin troubleshooting: - Check the fuse associated with the B2S1 O2 sensor (typically a 10A fuse in the engine compartment) - Verify if there is 12 volts at the sensor's pink wire (heater circuit) - Confirm that the sensor is properly grounded via the black wire - Measure resistance between the pink and black wires — acceptable range should be between 3.5 and 14.0 ohms I'm currently unable to access the sensor for inspection, but I'll follow the suggested steps once I can get to it. Any additional insights or common fixes would be greatly appreciated. Note: This truck is primarily used for RV towing and sits idle frequently, which may contribute to intermittent electrical issues.

Related fault codes
P0155
Comments (5)
Anonymous 2015-04-05 13:12

No other diagnostic codes are present. First step: check the B2S1 O2 sensor heater circuit fuse. Then verify 12 volts at the pink wire (heater circuit) and ensure proper grounding via the black wire. Measure resistance between the pink and black wires — it should fall within 3.5 to 14.0 ohms. Please share your findings so we can proceed with further troubleshooting.

Anonymous 2015-04-05 15:13

No additional codes are showing up on the scan tool. I'm unable to access the sensor or perform diagnostics until tomorrow, but I'll update you as soon as possible. Thanks for the helpful guidance — much appreciated. Lee

Anonymous 2015-04-05 15:52

You don't need to remove the sensor — simply probe the wiring harness with a multimeter or test leads to check voltage and resistance.

Anonymous 2015-04-06 10:01

I've checked the fuse and cleaned the contacts. After clearing the P0155 code, it hasn't returned yet. I've had similar intermittent issues before — often due to poor fuse connections or corrosion. I'll monitor the situation closely. If the code returns, I’ll inspect the wiring as suggested. Since this truck is used mostly for RV towing and sits idle frequently, electrical contact degradation may be a factor. Thanks again for the advice! Lee

Anonymous 2015-04-11 14:42

The P0155 code has returned. Can someone confirm where exactly the pink-black wire is located on the B2S1 O2 sensor? Also, am I measuring resistance from the pink wire to ground (black wire) or between the two wires themselves? Clarification would be helpful. Lee