BMW 118i - ignition switches itself off
| Data sheet | |
| Manufacturer | BMW |
| Vehicle model | 118i F20 |
| Engine | 1.6i |
| Engine code | N13 |
| Year of manufacture | 2011 to 2015 |
| Symptoms | Ignition switches itself off after a short time |
| Recommended HGS tool | megamacsX |
Ignition cannot be switched on – communication error with engine control unit (DME)
With the above-mentioned vehicle type, it can happen that the ignition cannot be switched on or only for a short time. The engine may also shut off at times. Communication errors are increasingly stored in the error memory, indicating that data from the engine control unit is missing.
If no definite faults have been detected in the periphery of the affected systems during the diagnosis, special attention should be paid to the main earthing connections on the gearbox and also on the engine.
As a result of their unprotected location, these cables can be corroded by external weather influences such as rain and road salt.
As a result, the contact becomes faulty or individual wires in the cable break, which reduces the cable cross-section. The faulty earth connection can cause the battery voltage to collapse briefly or completely under load on the control unit, which then disrupts communication between the control units.
In the course of further troubleshooting, all main earth connections must be visually checked for defects. If there are no visible defects, a voltage loss test should be carried out using a suitable measuring device.
If anomalies can be detected visually or if measurements are out-of-spec, replacing the affected cable can remedy the problem.
Once the cause of the fault has been rectified, delete the error memory and then carry out a test drive.
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