Error code
OBD2 P0099
OBD2P0099
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.
What it means
Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic.
Severity
moderateCan drive, but performance may be affected.
Summary
P0099 indicates an issue with Intake Air Temperature Sensor 2 (IAT2), which measures air temperature after compression in forced-induction engines.
Symptoms
- Poor engine performance, especially during acceleration
- Engine may run roughly or hesitate
Common Causes
- Poor connection or wiring issues between the ECM and IAT2 sensor
- Intermittent problems with the IAT2 sensor itself
- ECM programming errors requiring a reflash
Diagnosis
- Check for proper seating and condition of connector at IAT2
- Use a scan tool to monitor live data for IAT1 and IAT2 readings
- Perform DVOM checks on the sensor and wiring harness
Fixes
- Repair or replace faulty wiring, connectors, or sensors as needed
FAQ
What should I do if my car has P0099?
Check for loose connections, damaged wires, and perform sensor tests. If issues persist, consult a mechanic.
Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.
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