P0172

Description
System Too Rich (Bank 1)

The oxygen sensor in bank 1 detected a rich condition (too little oxygen in the exhaust).

Symptoms
You will more than likely not notice any drivability problems, although there may be a misfire.

Causes
A code P0172 may mean that one or more of the following has happened

• The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled.
• Vacuum leak.
• Fuel pressure or delivery problem
• Throttle position sensor

Possible Solutions

• Inspect all vacuum and PCV hoses, replace if necessary
• Clean the MAF sensor.
• Inspect fuel lines for any defects, leaks, or damage
• Check the fuel pressure at the fuel rail
• pull vacuum line at fuel pressure regulator, check for gas in vacuum line.
• Check the fuel injectors, clean if needed
• Test the TPS
• Check for an exhaust leak before the first oxygen sensor

__________________