Faulty intake air temperature sensor 1 on bank 2.; Damaged or corroded wiring harness or connector at the sensor.; Open or shorted circuit in the signal or ground wire between the sensor and PCM.; Poor electrical connection at the PCM connector.; Failed PCM (rare but possible).; Aftermarket modifications or accessories that interfere with the sensor circuit.

DTC codes / U06xx · Network communication / U0612

U0612Lost Communication With Intake Air Temperature Sensor 1 Bank 2

The U0612 code indicates that the powertrain control module (PCM) has lost communication with the intake air temperature (IAT) sensor 1 on bank 2 of the engine. The PCM monitors the sensor's data circuit and sets this code when it fails to receive a valid signal for a calibrated period, often due to an open circuit, short, or faulty sensor.

SystemNetwork

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaNetwork communication

Symptoms you may notice

Illumination of the check engine light (MIL) on the dashboard.
Often no symptoms besides the warning light, as the PCM may substitute a default intake air temperature value.
Possible decrease in fuel economy or slight driveability issues under certain conditions.
In rare cases, rough idle or hesitation during acceleration if the default value is significantly off.
Failure to pass an emissions inspection due to the stored code.
Remote start or other features that rely on intake air temperature data may be inoperative.

Common causes, most likely first

Faulty intake air temperature sensor 1 on bank 2.
Damaged or corroded wiring harness or connector at the sensor.
Open or shorted circuit in the signal or ground wire between the sensor and PCM.
Poor electrical connection at the PCM connector.
Failed PCM (rare but possible).
Aftermarket modifications or accessories that interfere with the sensor circuit.

How to diagnose and fix it

Use an OBD-II scanner to verify the code and check for related codes in other modules.
Inspect the IAT sensor and its connector for physical damage, corrosion, or loose pins.
Perform a visual inspection of the wiring harness for chafing, breaks, or shorts.
Measure the resistance of the IAT sensor with a multimeter and compare to specifications; replace if out of range.
Check for continuity and voltage on the signal and ground circuits between the sensor and PCM.
Repair any wiring faults found, such as splicing broken wires or replacing damaged sections.
Clear the code and test-drive the vehicle to confirm the repair; if the code returns, further diagnose the PCM.

Common Missteps in U0612 Diagnosis

A common oversight is replacing the IAT sensor without checking the wiring harness, which is often the real culprit due to heat and vibration damage.
The code can be set by a poor connection at the PCM, so technicians should not overlook cleaning and testing the PCM connectors.
Some vehicles use a combined mass airflow (MAF) and IAT sensor; in such cases, the entire MAF sensor may need replacement, but this code specifically refers to IAT sensor 1 on bank 2, which may be separate.
Intermittent communication loss can be caused by a faulty ground connection, so checking ground points is essential before condemning the sensor.
The PCM may default to a fixed intake air temperature value, masking driveability symptoms, so the absence of noticeable issues does not mean the fault is unimportant.

Can I keep driving with U0612?

The vehicle is generally safe to drive with this code because the PCM substitutes a default value, but fuel economy and emissions may be slightly affected. Avoid prolonged driving and schedule a diagnosis soon to prevent potential secondary issues.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.