BMW i3 Rex EME Units – Trials and Tribulations

We’ve seen a number of BMW i3 Rex EME issues now and are starting to gain a little knowledge and experience in their repair.

Each issue has been unique to date.

Case Study 1:

One example was a 2017 i3 Rex model with a 94Ah battery. This vehicle wouldn’t come out of ‘Park’. It would start – get to ‘Ready’ Mode but you just couldn’t move the selector from Park; No Drive, no Reverse, no Neutral etc.

It was effectively ‘locked’ in Park.

The component that governs the locking and unlocking is the ‘Park Lock Module’ (funnily enough!)

A previous garage had replaced this component to no avail.

It’s controlled and actuated via the EME Unit.

There are 6 (low voltage) wires between EME and Park Lock Module: 2 to physically actuate the lock motor and 4 to report on motor position (Hall Effect Sensors).

Testing the wiring is straightforward. It was found that the EME was not supplying a power or ground to the Park Lock Module motor.

Only the EME could be at fault for this.

The EME for the 94Ah model i3 REX is costly. (£6000.00 or thereabouts off the top of my head.) For this vehicle (with high mileage), buying a new unit from BMW was out of the question.

We sourced a used one quite quickly from eBay.

It certainly wasn’t as straightforward as just fitting and driving away though!

EME units have the VIN number of the vehicle they belong to written into them. This is a security feature. Fit a 2^nd hand EME to a different car than was intended and you aren’t going anywhere fast.

We like a challenge though(!) We managed to find a whizzkid who was able to ‘virginize’ our 2^nd hand unit. We were then able to program it successfully to the vehicle and ‘hey presto’, we were back up and running.

Case Study 2:

The second case study was also relating to the EME from a BMW i3 REX but this time, the battery size was 60Ah.

The symptoms were that ‘Ready Mode’ wasn’t attainable (you couldn’t start the vehicle).

Upon scanning the vehicle, our scan tool wasn’t picking up the EME Unit – it wouldn’t communicate with it.

In this situation, the tests and checks to carry out are fairly black and white:

Is unit receiving power? Does unit have its grounds? Do the communication networks have integrity?

The answer was a resounding ‘Yes’.

Only conclusion: faulty EME Unit, replace it.

The 60Ah unit is priced a little more friendly than its bigger brother – £3227.27 + VAT.

Our customer agreed to a new unit from BMW.

It arrived next day, we fitted it and programmed it.

Bingo! Vehicle starts and drives. Everyone happy.