BMW X1 X1 xDrive18d common faults.

2009–2012, SUV, diesel, 143 HP.

The fault list covers: N47D20 engine, ZF6HP-BMW, ZF8HP transmission.

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6 fault write-ups. All are important. 10 recalls.

If you know the year, pick it. Faults for other years drop out of the list.

Before you buy

Known faults

6 important faults

critical3

Diesel high pressure pump: power loss and engine shutdown while driving

critical

The high pressure pump of these common rail diesels (Bosch CP4) can fail while driving. The characteristic course is not gradual: a "Drivetrain fault" message appears on the dash, and within a few seconds the power is gone, on the motorway too. Afterwards the engine often cranks but will not start.

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What makes the repair expensive: once the inside of the pump wears, metal debris travels through the rail and contaminates the entire fuel system. At that point replacing the pump is not enough: the injectors, the rails, the tank and the lines go with it. That is the difference between a "pump replacement" and a "full system replacement" quote, that is what you should ask about.

The maker started a recall for this in the United States (NHTSA 21V586000, 2014 to 2018 328d / X5 xDrive35d / 535d / 740Ld / X3 xDrive28d). The same campaign did not run in Europe, even though the same pump works in the 320d/520d/X3 20d versions that are common right across Europe. The recall does not cover these cars.

between 79,000 and 248,000 km

What to check

Ask whether there has ever been a "Drivetrain fault" message or a loss of power while driving
Ask for the service history: if the high pressure pump was replaced, check whether the injectors and the lines were replaced with it. If not, the debris may still be in the system
After a cold start listen to the engine at idle: irregular running or smoke is suspect

3 more steps in the write-up

N47 / N57 diesel: timing chain on the rear of the engine

critical

In these diesels BMW put the timing chain at the back of the engine, on the gearbox side. The chain, the guides and the tensioner wear early. The symptom is a metallic rattle on a cold start that quietens once warm.

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The engine or the gearbox has to come out for the replacement, so the labour is a multiple of the parts cost. If the chain breaks or jumps, the engine is badly damaged inside, and the repair is an engine rebuild.

The problem is worst on engines built between March 2007 and March 2011, and the ones before early 2009 are the worst of all. The maker handled it under a service campaign in several European markets, but in the United Kingdom there was no formal recall. "It was never recalled" does not mean the chain is fine.

According to the German technical press the fault affects the whole N47 series and every power output, inspection is advised from 100,000 km, and factory revisions closed the matter around 2013, so cars built after 2013 are in a significantly better position. Stretching is typically preceded by a distinct rattle.

between 100,000 and 200,000 km

What to check

Insist on a cold start: the car should stand overnight, and the seller must not start it before you arrive
At the moment of starting, stand behind the engine (on the gearbox side) and listen to the first 3 to 5 seconds
A metallic rattle from the back of the engine calls for immediate expert inspection: this is not "diesel noise"

2 more steps in the write-up

Diesel EGR cooler: cracking, coolant in the intake, fire risk

critical

The internal fins of the exhaust gas recirculation cooler crack over time, and glycol coolant leaks into the intake, where it mixes with soot. The sticky mixture can ignite at high temperature: it can melt the plastic intake manifold and, in extreme cases, cause an engine bay fire.

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The maker recalled the 2013 to 2018 four and six cylinder diesels, roughly 800,000 cars worldwide. The first repair attempt proved insufficient, and the leak returned in several cases: the cooler fitted since 2022, from a different supplier, is the valid fix.

So "the recall was carried out" is not enough on its own: you have to check when, and which repair was done. A first round repair does not by itself rule the problem out.

The early symptoms are white, sweet smelling exhaust smoke, slowly dropping coolant, and a rough idle.

It shows up on diesels built between 2013 and 2018. The earlier M57 is not covered by the recall.

between 108,000 and 222,000 km

What to check

Check the level in the expansion tank, and ask whether it has needed topping up
After a cold start watch the exhaust: persistent white smoke and a sweet smell mean the coolant is burning
Ask for the service book and find the EGR cooler recall entry: Check the date too

2 more steps in the write-up

expensive3

XDrive transfer case (ATC): binding in corners, plastic actuator gear

expensive

The heart of the four wheel drive in the longitudinal engine BMW X models (X3, X5 and the X1 E84) is the ATC transfer case. It has two faults, and you can feel both while driving.

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The first is wear of the clutch pack and the fluid: in a slow, tight corner (a car park, a roundabout) the car jerks and "hops", as if the drive grabbed and let go. You can also get a jerk when pulling away on a slope. The second is the plastic actuator gear: the position signal is lost, the brake, ABS and 4x4/DSC lights come on together on the dash, and a clicking is audible from the transfer case when you switch the ignition off.

Workshops often propose a full transfer case replacement straight away. But the plastic gear can be replaced on its own, and the wrong tyre size or a mixed set of tyres also imitates the jerking, because the transfer case then slips continuously. So clear up the tyres and the fault code first, before you pay for a transfer case replacement.

between 72,000 and 175,000 km

What to check

In a slow, tight corner (a car park) watch for jerking, binding and a "skipping" feel
When pulling away on light throttle, can you feel the drivetrain jerk
Watch the dash: 4x4, ABS, DSC and brake lights together point at the actuator

4 more steps in the write-up

ZF 6HP automatic: mechatronics connector sealing sleeve leaks

expensive

In the ZF six speed automatic (BMW codes GA6HP19Z / GA6HP26Z) the electrical connector of the valve body control leaves the gearbox housing through a plastic sleeve. That sleeve and its seals age, and they let oil through.

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The symptom is irregular shifting, a gear slipping at higher revs, limp mode, a drivetrain fault code and a message on the display. The cause is the same in each case: the leak drops the hydraulic pressure, and the valve body cannot close the clutches with enough force.

The sleeve can be replaced without removing the gearbox, you only have to drop the oil pan. If it leaks for a long time, the slipping clutch and the overheating pump take the inside of the gearbox with them, and from then on it is a rebuild. The factory calls the oil a lifetime fill, but in practice the sleeve wears out around 60,000 to 70,000 miles, roughly 100,000 to 115,000 km.

between 100,000 and 200,000 km

What to check

On a lift look at the right side of the gearbox housing, above the oil pan: a wet, oily connector is the characteristic picture
On the test drive watch the shifts cold and warm: jerking, delay, slipping at higher revs
Ask for a fault code read from the gearbox controller: gear ratio fault, pressure regulation

2 more steps in the write-up

ZF 8HP automatic: mechatronics unit and connector sleeve leak

expensive

The ZF eight speed automatic (BMW Steptronic 8HP family) has two faults, and you can feel both.

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The first is the mechatronics unit: the valve body and the control electronics in one. If the solenoids or the pressure regulation weaken, the gearbox jerks, the D/R engagement is delayed, it logs a gear ratio fault code, and finally drops into limp mode (often staying in 2nd or 3rd).

The second, and often misdiagnosed, is the connector sleeve of the mechatronics unit: the O-ring of the plastic sleeve ages, and ATF leaks from the side of the housing, exactly where the wiring harness enters. This is easy to mistake for a rear crankshaft seal. The trail starts from the driver's side of the housing, not from the clutch side.

On cars built in 2023 there was also a separate safety recall for a welding fault in the mechatronics unit. That is not the same as the wear related sleeve and the valves.

Check the fluid level, the area around the sleeve and the fault codes first; do not accept a "full gearbox replacement" quote straight away.

above 120,000 km

What to check

On the test drive watch for delayed D/R engagement, a jerk when shifting, and limp mode (a stuck gear)
Look at the driver's side of the gearbox housing where the wiring harness enters: an ATF trail from the sleeve is suspect
Do not confuse it with a rear crankshaft seal leak: the direction of the trail decides

3 more steps in the write-up

Official recall10 recallsShow

The manufacturer fixes these for free at a franchised dealer. Ask with the VIN whether it was done.

Most recent: 30 March 2023

A12/00868/23Safety recallInjuries30 March 2023 · EU Safety Gate

The airbag may deteriorate over time, and if deployed, excessive internal pressure may cause the inflator body to burst and metal fragments could pass through the cushion material causing injury to occupants. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: 30/03/2023

We could not check this: model year. The authority's notice

A12/01929/23Safety recallInjuries29 June 2021 · EU Safety Gate

The propellant in the driver airbag can deteriorate due to high humidity and temperature variations. In the event of an accident in which the airbag deploys, this could result in fragments from the inflator casing coming loose and injuring the vehicle’s occupants. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: 29/06/2021

We could not check this: model year. The authority's notice

A12/00039/20Safety recallInjuriesno date · EU Safety Gate

The connector of the positive battery cable on the front power distribution box may be damaged over the lifetime of the vehicle by vibrations and currents. This may lead to failure of the engine and of the vehicle's electrical system, including headlights and occupant protection which will increase the risk of an accident and injuries to the occupants.