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Steve, BMW Expert
Category: BMW
Satisfied Customers: 25390
Experience:  BMW Expert
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Just purchased a BMW 06 plate 520D SE touring and having starting

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Just purchased a BMW 06 plate 520D SE touring and having starting problems. The garage have replaced the starter and the crank shaft sensor but still has problems.

The car struggles to start when cold, but when it has fired up it runs fine, leave it for 30 mins and it starts, possibly as still warm engine but sometimes it struggles, the garage (not BMW specialist) is scratching its head as too what the fault could be, they think it's electrical.

They have had it a week now. When it is running it is 100% spot on.
what exactly has been tested thus far?
Customer: replied 4 years ago.
They replaced the starter motor and the crank shaft sensor and put a new heavy duty battery on it.
Next they have ordered two new relays not sure they are, but something to change before fitting new ECU.

They said when starting it shows a voltage fault, registering More than it should but it fluctuates. When running it clears and runs properly.
what fault exactly does it show?
Customer: replied 4 years ago.
I am not sure, they have only told me what I have told you apart from when tested they expected the voltage fault to show less than twelve but it showed up to 24 volts

there are some issues with battery cables and power distribution on this model. this needs to be checked.


also the alternator and battery (despite being new) need to be tested, and the vehicle tested for a parasitic battery draw


it is unlikely for an ECU to fail in this model, so I am not sure why they would be leaning that way, especially if they are not BMW specialists.


my best advice would be to move the car to a BMW specialist. If this shop does not specialize exclusively or near-exclusively on BMWs, then they are most likely not equipped to fully diagnose this car and are going to end up guessing further with your money.


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