Before you buy a used Mercedes-Benz EQA / EQB / EQC / EQE / EQS / EQV.

Look out for: Risk of an internal short circuit in the high-voltage battery; leaking coolant reservoirs and faulty distribution valves; sporadic failures of driver aids (high beam, lane keeping, emergency braking, camera) and of the charging flap.

Ask them to check: Check recall 16136R by VIN and follow the charging instructions until the repair; check the coolant level.

Look out for: The heating gives little heat (and the air conditioning cools poorly); the driver often remembers a single loud “plop” during a journey. B19A200 (electric compressor overtemperature) or P053400 (refrigerant level too low) may be stored.

Ask them to check: The garage reads the climate-control codes, looks at the line between compressor and condenser and checks the dryer cartridge filter. According to the bulletin, a noisy compressor alone is no reason to replace it: it has to match the codes or the particles.

Look out for: While driving the coolant-level-too-low message appears and the yellow warning light comes on, with P25567B stored; when the cap is opened the level is fine again.

Ask them to check: Do not top up blindly or open the reservoir when hot. If the level is right when cold and there are no leaks, the garage swaps the black cap of the large chamber for the red one and raises the level about 20 mm above the maximum; if that is not enough, it fits the modified reservoir. If the level really drops, look for a leak.

Look out for: When stationary or below about 11 km/h, for example when parking, the steering is only partly assisted. No warning appears and no code is stored. It works normally again after switching off and on or above that speed, but it may come back.

Ask them to check: If the steering gets heavy at low speed without any warning, ask Mercedes for the steering software update before replacing parts. If it also gets heavy while driving or a steering warning appears, stop somewhere safe and call for assistance.

Look out for: Several fault messages appear in the instrument cluster, especially if pre-conditioning starts or the ignition is switched on with the charging cable plugged in; power may be reduced. The rear-axle power electronics (N129/2) store P061AE9 and sometimes others such as U009BFF, P0A31FF or P0A1C9A.

Ask them to check: Check whether the car has a rear motor (4MATIC) and whether P061AE9 is in unit N129/2. Before replacing the motor or its electronics, ask Mercedes for the software update; if the code comes back afterwards, the garage opens a technical case with the brand.

Look out for: When reversing very slowly (below about 6 km/h) a squeal comes from the drive unit; it does not happen going forwards.

Ask them to check: If the squeal only happens when reversing slowly, with no warnings and no loss of power, the bulletin says no part should be replaced. If there are warning lights, coolant loss or noise going forwards too, have the garage check it.