What Does P1161 Mean?
This code indicates the Intake Air Temperature (IAT) sensor circuit is either open or shorted to the positive voltage supply. When the signal wire is open, the PCM sees maximum voltage (approximately 5V), interpreting it as extremely cold intake air. A short to positive (B+ or 5V reference) produces a similar effect. This causes the PCM to command richer fuel mixtures than necessary, increasing fuel consumption and emissions.
Common Causes
30%
Open circuit in the IAT sensor signal wire (broken wire or disconnected)
25%
Failed IAT sensor with open internal thermistor element
20%
Corroded or spread connector pins at the IAT sensor causing loss of contact
15%
Signal wire shorted to 5V reference wire in the harness bundle
10%
PCM connector issue with the IAT signal input pin
Diagnostic Steps
1
Read the IAT value in live data; a fixed reading of -40°F (-40°C) confirms the PCM sees an open or high-voltage condition.
2
Disconnect the IAT sensor and measure resistance across the sensor terminals; compare to the resistance-temperature chart (approximately 2,000-3,000 ohms at 68°F/20°C). An infinite reading confirms an open sensor.
3
If the sensor resistance is correct, check for continuity of the signal wire from the sensor connector to the PCM connector.
4
Inspect the connector for backed-out pins, corrosion, or terminal tension issues; repair as needed.
5
If the signal wire shows continuity but the issue persists, check for a short between the signal wire and the 5V reference wire in shared harness sections.
Estimated Repair Cost
$50 - $200
Parts + labor, varies by vehicle and location
This code indicates the Intake Air Temperature (IAT) sensor circuit is either open or shorted to the positive voltage supply. When the signal wire is open, the PCM sees maximum voltage (approximately 5V), interpreting it as extremely cold intake air. A short to positive (B+ or 5V reference) produces...
The most common cause of P1161 (Intake Air Temperature Sensor Open/Short To Positive) is: Open circuit in the IAT sensor signal wire (broken wire or disconnected)
Typical repair costs for P1161 range from $50 to $200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The engine will run excessively rich, increasing fuel consumption and carbon monoxide emissions. While not an immediate safety hazard, prolonged rich operation can foul spark plugs, degrade the catalytic converter, and reduce engine performance.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1161 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel / Air Metering
Difficulty
Type
Manufacturer
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