BMW F25 F26 Engine Intermittently Will Not Start at Very Low Outside Temperatures

BMW engine will not start at times at very low outside temperatures (-4°F/-20°C and colder); however, the battery state of charge is correct and the starter turns the engine over properly.This starting difficulty is most likely to occur after shutting the engine off briefly for 5 or 10 minutes, such as when refueling.

The following faults are most likely stored in the DME:

N20 engine:

• 1B5202 – Terminal 15N_1: No voltage
• 1B5302 – Terminal 15N_2: No voltage
• 1B5402 – Terminal 15N_3: No voltage

N52T engine:

• 1B5102 – Terminal 15N_3: line from CAS, electric: short circuit to earth
• 1B5501 – Terminal 15N: No voltage
• 1F0601 – Terminal 15N from CAS, switching delay: Switches too late

N55 engine:

• 1B5202 – Terminal 15N_1: No voltage
• 1B5302 – Terminal 15N_2: No voltage
• 1B5402 – Terminal 15N_3: No voltage

 

In addition, other engine electronic power supply-related faults could be stored for components such as VANOS solenoids, camshaft sensors, engine oil pressure sensor, engine oil pressure control valve, engine oil level sensor, etc.

 

CAUSE

At very low outside temperatures, low levels of moisture present inside the power distribution module (PDM) can freeze the internal micro-relay contacts.

 

CORRECTION

F25 and F26

Replace the PDM module and install the cover (if not already present) with the plastic rivet.

 

Important:

Follow the instructions in the attachment. This will help ensure that the power supply wiring does not contact the cover.

 

F15 and F16

Replace the PDM module and install the cover (if not already present) using the existing mounting screw.

 

Important!

The replacement PDM module part number listed below is only to be used in the case of a failure at very low ambient temperatures, as described above.

All other repairs requiring a PDM replacement must be done using P/N 12 63 7 591 534 and/or as specified in ETK