Charge Air Temp / Intake Air Temp Correlation Bank 1
The P011C code indicates that the Engine Control Module (ECM) has detected a discrepancy between the Charge Air Temperature (CAT) sensor and the Intake Air Temperature (IAT) sensor readings for Bank 1. This typically occurs when the two sensors report temperatures that differ by more than a calibrated threshold, suggesting a fault in one of the sensors, wiring, or a mechanical issue like a stuck thermostat or boost leak. The ECM uses these inputs for fuel trim, ignition timing, and boost control, so incorrect readings can affect performance and emissions.
01. Most Common Causes
- Faulty Charge Air Temperature sensor
- Faulty Intake Air Temperature sensor
- Wiring or connector issues (corrosion, damage, loose connection)
- Stuck open thermostat causing slow warm-up
- Boost leak or vacuum leak affecting temperature readings
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or hesitation
- Poor fuel economy
- Rough idle or stalling
- Possible black smoke from exhaust (rich condition)
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional related codes.
Step 2: Visually inspect the CAT and IAT sensors and their wiring for damage, corrosion, or loose connections.
Step 3: Compare live data from both sensors with a scan tool; they should be similar when engine is cold and diverge as engine warms.
Step 4: Test sensor resistance and voltage according to manufacturer specifications.
Step 5: Check for boost leaks or vacuum leaks that could affect temperature readings.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short trips, but prolonged driving may cause reduced performance, poor fuel economy, and potential damage to the catalytic converter due to incorrect air-fuel mixture.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on whether a sensor needs replacement and the vehicle make/model.