P0407
PowertrainEgr Systemmoderate severityExhaust Gas Recirculation Sensor B Circuit Low
What P0407 Means
The PCM detects a low voltage signal from EGR sensor B. This can reduce EGR control accuracy and increase emissions.
Symptoms
- Check engine light on
- Rough idle
- Increased NOx emissions
Common Causes
- Faulty EGR position sensor B
- Short to ground in wiring
- Corroded connector
- Failed PCM input circuit
Diagnostic Steps
- Scan and record freeze frame
- Backprobe EGR sensor B signal voltage
- Inspect wiring for short to ground
- Replace EGR sensor or repair harness
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