BMW Misfires Due To Winter Blend Fuels
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BMW Misfires Due To Winter Blend Fuels

Here’s how to cure the problem on i3 models with range extender engines.

Models 

E-Series I01 i3 

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On the i3 models with the range extender (REx) engine, the MIL will be illuminated and will run rough for about 1 to 2 seconds during cold start. It is also likely that one or more of the following fault codes are stored in the Range Extender Digital Motor Electronics (RDME) with a frequency of 5 or less with no other faults stored. 

125001: Combustion misfire, cylinder 1: Combustion quality too low 

125002: Combustion misfire, cylinder 2: Combustion quality too low. 

125003: Combustion misfires, several cylinders: Combustion quality too low. 

CAUSE

The issue described occurs during the winter months with the use of high-octane winter blend fuel at high altitude areas greater than 3,500 feet, such as Colorado & Utah. Specifically, when the REx engine is being operated while driving at or above this altitude because the remaining high-voltage battery charge has dropped below the specified level. Fuel pumps may be labeled as dispensing winter fuel, based on state regulations. 

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CORRECTION

A new fuel additive (ADVANTEC Protect) can cure the problem. For conditions that are like the situation described: 

  1. Perform diagnosis with a scan tool. 
  2. If the vehicle meets the winter fuel blend usage and high-altitude operating criteria, drain the fuel tank. 
  3. Add a full bottle (100 ml) of additive to the tank. 
  4. Refill the tank with the available winter-blend medium octane fuel (Recommended 89 octane). 
  5. Perform the “Service Start Range Extender” Service Function: Service functions > Drive > Range Extender Digital Motor Electronics > Service Start Range Extender Select the option “operation at the standard rotational speed (2400 rpm)” and let run till completion. 
  6. Verify that the misfire is no longer occurring. 
  7. Please explain to the customer that they need to add a full bottle of additive every time they periodically refill the complete fuel tank. This additive and the recommended octane fuel are only required while the winter fuel-blend is available and used. 

The additive is only effective for the exact situation described. In all other misfire situations, please perform normal misfire diagnosis.

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