Intake Air Temperature Sensor 2 Circuit High (GM)
What does P1534 mean?
The P1534 code means the vehicle's onboard diagnostic system has detected: Intake Air Temperature Sensor 2 Circuit High (GM). This is a low severity code.
Common Symptoms
- Check Engine Light illuminated
- Slightly lean fuel mixture
- Marginally reduced fuel economy
- No noticeable drivability symptoms
- Scan tool shows abnormally low intake air temperature
Probable Causes (Ranked by Likelihood)
- Failed open IAT2 sensor Very High
- Disconnected IAT2 sensor connector High
- Open circuit in the sensor wiring Moderate
- Corroded connector pins Moderate
- ECM input circuit fault Low
Step-by-Step Diagnostic Procedure
-
Read the IAT2 sensor value on a scan tool. An extremely cold reading on a warm day confirms the open circuit.
-
Check the IAT2 sensor connector to make sure it is plugged in securely.
-
Measure sensor resistance. An open reading (infinite ohms) indicates sensor failure.
-
Check wiring continuity between the sensor and ECM.
-
If the wiring and connector are good, replace the IAT2 sensor.
Frequently Asked Questions
Can a disconnected sensor cause P1534?
Yes. If the IAT2 sensor connector comes unplugged or has a broken wire, the ECM sees an open circuit (infinite resistance) and reads it as an extremely cold temperature, triggering this code.
Is this the same as the MAF sensor?
No. The IAT2 sensor measures air temperature only, while the MAF sensor measures air mass flow. Some MAF sensors have a built-in IAT sensor, but IAT2 is a separate sensor on GM vehicles.
How do I test the sensor?
Measure the resistance between the two sensor terminals. At 70F it should read approximately 2000-3000 ohms. At 200F it should be around 200-300 ohms. No reading (infinite) means the sensor is open.