XSeries-forum

Had a right time with the old battle axe this week, knocking on 307K miles and still chugging on!

Noticed a heaviness in the power steering at very low speed at opposite locks at beginning of week, checked the fluid reservoir and notice it was just below minimum.

Topped it up the next day evening with CHF11S fluid, then drove to a nearby town for a run out, all seemed ok.

Had some scran and then drove back home after the sun had set, approx. 30 minute journey 15 minutes into the journey red battery light came on, then yellow 4x4, then yellow gearbox light, then yellow battery light! The dashboard was merrily pinging away faults!

I've got the BimmerLINK app and blue tooth OBD dongle, so ran the fault codes:

4BDA low pressure fuel control
4A17 Generator (Layer_GEN)
4A66 power management wiring system (Layer_PMBN)
5014 Supply Voltage
55C3 VGS four-wheel -drive system activated. No DXC setpoint default.
55CE CAN_MESSAGE_GETRIEBEDATEN, BA
5DCE - Uz supply voltage_terminal_15 error: slight under voltage; Voltage too low--- (DCS:DCS control unit under voltage)
5F2F - 5F2F - EGS error
6E22 - DME error
(There were more but have given up typing them out..)

Initially thought I had caused a short circuit due to bashing the rear reg plate lamps to turn back on before setting off previous to the faults.

I promptly turned off all electrical devices I could on the car, as I knew things like the gearbox needed power to run, I somehow managed to get home, put the car into reverse and then everything cut out. Tried to restart the engine and the battery was dead.

I disconnected the rear Reg plate lights and then did a battery test (all ok) and then recharged the battery overnight and run another battery test ok. I started the engine up the next morning turned the lights on and left it running for about 20 mins --> red battery light appear, turned car off and then it would not restart. Battery tester said it had 0% charge. Assumed I had a faulty battery or really bad short but no tell tail signs of melting wire insulation.

Obtained an new battery, reset all the fault codes, registered the new battery, and then drove 300 miles with no power problems, apart from the power steering still wasn't right, it was ok at speed on motorway but when slowed down has intermittent heavy steering.

I think this could be very dangerous and I may end up hitting something at low speeds when turning.

Any ideas what this could be? No steering faults are showing on BimmerLINK. Could it be a slipping belt?

Going to start investigating tomorrow morning.

Congrats on getting to 300k thats some achievement as there are no faults maybe jack up the front and if its hard to move the wheels lock to lock by hand with the engine off incase its a siezed topmount or steering joint ..
There was a recall on a pulley bolt near the alternator that if it breaks throws the aux belt and smashes the alternator ,it may have been changed but given the miles it might need done again.
Failing that the rack might be worn out and need replaced .

Might be the pump itself, or if the level got too low then air in the system. It does self bleed but needs the wheels turning from lock to lock a few times to help clear the air out. The manual says to do this twice in each direction with the engine running (not that you’d want to try it without!).

If it was low, then where did it go? It doesn’t evaporate in our temps so you may have a leak. E53 PAS hoses had an issue around 2004/5 with many having to be replaced under warranty (mine were). Worth checking in case your E70 ones are time expired. Might be seals on the rack itself. Time to look for wet spots!

Glad the battery was the major issue though. We know how BMWs love to throw all sorts of battery isn’t perfect. You’d think there’d be a warning to tell you it’s the battery that’s knackered!

Thanks for the info Gents, I've not investigated yet but after driving for 5 hours yesterday I started up this morning and the steering was very heavy coming off the drive, but then eased up about 5 minutes into the journey?

Could well have bled itself through if it stays OK.

My pas tank was a little low and had been for some time , they do lose a little over a lot of miles ,never made any difference to the steering so id say you have some sort of issue , a failing battery does cause all sorts of wierd issues, a drop in voltage made my autobox hold onto gears when you floored it and just sit a near 5k and refused to change up but the pas is hydraulic rather than electric though I'm guessing there is some electric component in it . Time will tell I'm not sure how the pas oil is cooled but it could be some sort of oil overheating issue which shows up at low speed when the oil is working harder with more turning .

Just took it out on school run, same issues remain at start up.

Slow pressure build up so could be the pump isn’t working well, or there’s a fluid leak. If the level has dropped then it’s a leak. Is the belt tight or contaminated by any chance? (It’ll probably squeal a lot if it is loose though).

There is an option called Dynamic Drive and that needs initialising and requires use of the MODiS BMW software. That’s normally only needed if the valve block has been changed, or air is in the system. Do you have that option on the car? I don’t think many do, but….

No reference to any electric assist on the E70.

Don't think I have Dynamic Drive, will lift the car and have look tomorrow if its not raining....