P0172 System Too Rich (Bank 1)

Description and meaning of DTC p0172

This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. Although generic, the specific repair steps may vary depending on make/model. Basically this means that an oxygen sensor in bank 1 detected a rich condition(too little oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the sideof the engine that has cylinder #1. Note: This DTC is very similar to P0175, and in factyour vehicle may show both codes at the same time.

p0172 diagnostic trouble code symptoms

You will more than likely not notice any drivability problems, although theremay be symptoms such as a misfire.

DTC p0172 - possible 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. There is also an issue with some vehicles where the MAF sensors leak the siliconepotting material used to protect the circuitry. There could be a vacuum leak. There could be a fuel pressure or delivery problem

How to fix OBD-II diagnostic trouble code p0172

Possible solutions include:Inspect all vacuum and PCV hoses, replace if necessaryCleanthe MAF sensor. Consult your service manual for it's location if youneed help. I find it's best to take it off and spray it with electronics cleaneror brake cleaner. Make sure you are careful not to damage the MAF sensor,and make sure it's dry before reinstallingInspect fuel lines for cracks, leaks, or pinchesCheck the fuel pressure at the fuel railCheck the fuel injectors, they may be dirty. Use fuel injector cleaner orget them professionally cleaned/replaced. Check for an exhaust leak before the first oxygen sensor (this is unlikelyto cause the problem, but it is possible)

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