P0051 and P0155

[Guan Martin]

I have a 2004 Jeep Grand Cherokee Limited 4×4 with 4.7L V8 engine, and 83,000 miles. It produced codes P0051 and P0155. They indicate “heater control circuit low” and “heater circuit malfunction.” Can anyone tell me where Bank 2 Sensor 1 is located on this vehicle,and the best place to purchase the sensor?

Topic

[EricTheCarGuy]

V engines by design have one cylinder bank that’s closer to the front of the engine than the other. If you were to lay a ruler across the valve covers you’d find that one was placed further forward than the other, this is bank 1. Sensor 1 is the first sensor in the exhaust stream usually located in the exhaust manifold. So you’re looking for the sensor in the side of the engine that sits a little back from the front and closest to the engine.

[dreamer2355]

I would also check your fuses for your o2 sensors.

If you isolate the correct o2 sensor, you could disconnect it and ohm out the heater circuit for the o2 sensor. Usually when the heater circuit fails, it warrants a o2 replacement after testing obviously.

[Author]

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