C1612 UMM Alter is described as Fuel System Too Rich, which basically means bank 1's oxygen sensor has detected a rich condition of fuel. This means there's not enough oxygen in the exhaust from too much fuel being delivered into the air and gas mixture for combusion. As you drive and when specific conditions are slowly met, the vapors will gradually purge from the charcoal canister and will get burned within your engine.
SymptomsSymptoms of a C1612 UMM Alter diagnostic trouble code may include:
Possible Causes :
Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio. You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data.
Diagnostic trouble code C1612 UMM Alter is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.
Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before C1612 UMM Alter.
Fortunately, C1612 UMM Alter is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.