What Does P041C Mean?
The PCM has detected that the exhaust gas recirculation temperature sensor B circuit voltage is below the minimum expected threshold. This typically means the sensor signal wire is shorted to ground, the thermistor has failed in a low-resistance state, or there is excessive resistance in the 5V reference supply. The driver will see the MIL and may experience slight changes in EGR operation.
Common Causes
35%
EGR temperature sensor B signal wire shorted to ground
30%
Failed EGR temperature sensor B with internally shorted thermistor
20%
Water intrusion in the sensor connector causing low-resistance path to ground
10%
5V reference circuit high resistance reducing the voltage seen at the sensor
5%
PCM sensor input circuit pulled low internally
Diagnostic Steps
1
Monitor the EGR temperature sensor B voltage PID — if it reads near 0V or below 0.1V, the circuit is shorted low. Normal cold reading should be 3.5-4.5V for an NTC thermistor.
2
Disconnect the sensor connector. If the scan tool voltage jumps to 5V (or near it), the sensor is internally shorted. If it stays low, the short is in the wiring.
3
With the sensor disconnected, check the signal wire for shorts to ground using a multimeter from the signal pin to chassis ground. Any reading below 10K ohms indicates a harness short.
4
Inspect the connector for moisture, corrosion, or carbon tracking between pins. Clean with electrical contact cleaner and allow to dry completely before re-testing.
5
Verify the 5V reference voltage at the connector. If it is significantly below 5V with the sensor unplugged, there may be a reference circuit issue affecting multiple sensors.
Estimated Repair Cost
$75 - $300
Parts + labor, varies by vehicle and location
The PCM has detected that the exhaust gas recirculation temperature sensor B circuit voltage is below the minimum expected threshold. This typically means the sensor signal wire is shorted to ground, the thermistor has failed in a low-resistance state, or there is excessive resistance in the 5V refe...
The most common cause of P041C (Exhaust Gas Recirculation Temperature Sensor "B" Circuit Low) is: EGR temperature sensor B signal wire shorted to ground
Typical repair costs for P041C range from $75 to $300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive for short trips. The PCM will likely default to a fixed EGR strategy, which may slightly increase NOx emissions. Prolonged driving without EGR temperature feedback could allow detonation under load on some engines.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P041C to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Exhaust Gas Recirculation (EGR) System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
