What Does P044B Mean?
The EGR sensor 'C' signal is within the valid voltage range but is not responding as expected during EGR operation. This range/performance issue means the sensor reading does not match the predicted value when the EGR valve is commanded open or closed. The driver may notice slightly rough idle or increased emissions, along with a check engine light.
Common Causes
35%
Carbon buildup in EGR passages restricting flow, causing sensor readings that don't match expected values
25%
Degraded EGR sensor 'C' reading outside expected correlation range
20%
EGR valve not opening or closing properly (stuck, sticking, or worn)
10%
Exhaust leak near the EGR pickup point affecting sensor readings
10%
Intermittent wiring or connector issue causing erratic signal
Diagnostic Steps
1
Monitor EGR sensor 'C' live data while commanding the EGR valve open and closed using scan tool bidirectional controls. The sensor reading should change proportionally with EGR flow.
2
Inspect the EGR valve and passages for heavy carbon buildup. Remove the EGR valve and visually inspect the intake ports—heavy soot deposits indicate restricted flow that needs cleaning.
3
With the EGR valve removed, verify the valve itself opens and closes smoothly by applying vacuum (vacuum-operated) or commanding it electrically. Check for carbon preventing full travel.
4
Compare the sensor 'C' reading to sensors 'A' and 'B' (if present) during EGR operation. All should show correlated changes when EGR flow changes.
5
Check for exhaust leaks upstream of the EGR pickup point that could reduce EGR gas volume reaching the sensor.
Estimated Repair Cost
$150 - $550
Parts + labor, varies by vehicle and location
The EGR sensor 'C' signal is within the valid voltage range but is not responding as expected during EGR operation. This range/performance issue means the sensor reading does not match the predicted value when the EGR valve is commanded open or closed. The driver may notice slightly rough idle or in...
The most common cause of P044B (Exhaust Gas Recirculation Sensor "C" Circuit Range/Performance) is: Carbon buildup in EGR passages restricting flow, causing sensor readings that don't match expected values
Typical repair costs for P044B range from $150 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive. However, improper EGR operation can increase NOx emissions and may cause engine knocking or pinging under load, especially with low-octane fuel. Avoid sustained high-load driving until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P044B to identify the root cause.
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Quick Info
Category
Powertrain
System
EGR / Emissions System
Difficulty
Type
Generic (SAE)
Recommended Tools
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