P0172
System Too Rich (Bank 1)
Description
System Too Rich (Bank 1). This powertrain diagnostic trouble code covers the engine, the fuel and ignition systems, emission control and the transmission.
OBD Codes Details
Possible Causes
Faulty sensor, intake leak, clogged fuel filter, weak fuel pump, damaged wiring
Solution
Check for intake leaks, inspect and clean the sensor, measure fuel pressure, compare live data against the expected range
Symptoms
- Black smoke from the exhaust
- Strong fuel or sulfur smell from exhaust
- Rough idle
- Poor fuel economy
- Check engine light illuminated
Diagnostic Recommendations
- Check fuel pressure regulator for leaks
- Inspect MAF sensor for contamination or damage
- Test O2 sensors for correct rich/lean response
- Check for a clogged air filter restricting airflow
- Inspect fuel injectors for leaking or stuck-open condition
Repair Cost Estimate
- Fuel pressure regulator replacement: $100-250
- MAF sensor cleaning/replacement: $50-400
- O2 sensor replacement: $150-400
- Fuel injector cleaning/replacement: $200-800
- Total diagnostic and repair: $200-1500
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Fact-checking completed
Verified by:
Pavel Volkov
Created:
Information verified against official sources
Official Sources
Society of Automotive Engineers
Official OBD-II diagnostic trouble codes standard (SAE J2012)
Automotive engineering standards organization
International Organization for Standardization
International standard for vehicle diagnostic systems
International standards for automotive diagnostics
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