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P0042: The lambda sensor heater control (bank 1, sensor 3) has an electrical fault

The lambda sensor heater control (bank 1, sensor 3) has an electrical fault. It may be the part itself, its connector or the wiring.

Code P0042 at a glance
CodeP0042
SystemEngine and transmission
GroupP00xx, Air, fuel and emissions
TypeGeneric: it means the same on every make

How to read and clear P0042 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0042 with its description and whether it’s confirmed, pending or permanent.

If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.

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What does code P0042 mean?

The lambda sensor heater control (bank 1, sensor 3) has an electrical fault. It may be the part itself, its connector or the wiring.

How do you clear P0042?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0042 comes back.