P0112 OBD-II Trouble Code: IAT Sensor Circuit Low Input Problem

P0112 code definition

Intake Air Temperature (IAT) sensor circuit low input problem

What the P0112 code means

P0112 is the OBD-II generic code that the engine control module (ECM) has recorded the IAT sensor input below the expected sensor range.

What causes the P0112 code?

If the output voltage is less than 0.18 V for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets trouble code P0112.

What are the symptoms of the P0112 code?

• This ECM will turn on the Check Engine Light and go into a failsafe mode.
• The engine may be hard to start
• A fuel mileage reduction
• Exhaust may have black smoke out of the tailpipe on acceleration

Note: The symptoms are determined by the manufacturer failsafe ECM strategy for the vehicle during a failure and may vary between manufacturers and vehicles.

How does a mechanic diagnose the P0112 code?

• Scans the ECM, documents the codes received, and views the freeze frame data to see the conditions present when the code was set

• Clears the vehicle of fault codes and the retests the vehicle to see if the code comes back

• Performs a visual inspection to see if there is a disconnected or loose electrical connector to sensor

• Observes the sensor’s live data on the scanner while doing a wiggle test for an open circuit in wiring, connections or sensor

If no problems are noted, the mechanic performs manufacturer's specific pinpoint tests for the code and repair as needed.

Common mistakes when diagnosing the P0112 code

• Not performing visual inspections of connections and wiring

• Not following the manufacturer pinpoint test procedure step-by-step or skipping steps

• Not replacing an IAT sensor only when tests indicate a problem

• Not connecting a new or known good sensor to the harness and viewing the ECM data to see if the temperature output from the sensor is as expected

How serious is the P0112 code?

• The P0112 code will cause the engine ECM to go into a failsafe mode.

• The failsafe mode, depending on the manufacturer failsafe mode strategy, may cause erratic drivability symptoms.

• Driving the vehicle for an extended time with the vehicle in failsafe mode may require additional repairs to remove carbon or repair possible ignition problems.

What repairs can fix the P0112 code?

• Repairing or replacing the IAT connector
• Repairing or replacing the wiring as necessary
• Replacing the IAT with a new sensor

Additional comments for consideration regarding the P0112 code

• The P0112 code is often associated with P0111, P0113, and P0114 codes.

• Most intake air temperature sensor problems for code P0112 are failures from damaged or corroded harness connectors and the sensors failing internally.

Need help with a P0112 code?

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