My 535d seems to lose power between 2nd and 3rd gear under hard acceleration  leading to engine light coming on, code reader reports " throttle output circuit " fault? Is this a big fix or straightforward? Tia

Hi Steve

Welcome to the Forum

It could be the throttle body?Control Flap its self or just the Throttle position sensor. 

Take a look at www.realoem.com it's a BMW online parts list put the last 7 digits of your Vin in the search box it will bring up your model, then search for what you need. The small exploded drawings will help with location .

I would first check the associated loom and wiring for any sign of wear/chaffing also check Google for test methods for the throttle position sensor. If you need a replacement you have the correct part number again Google for best supply price

Neither are big jobs just need a bit of patience as other stuff is in the way

Dave

Morning Dave and thanks for the welcome! Cheers for advice I'll try that and see, do you think a more professional code reader would be able to narrow it down a bit more as mines only a hobby job?

Cheers 

Steve

Hi Steve

The best you can get is BMW ISTA diagnostic program which you can mount on your laptop. It will give you Dealer level diagnostic capability plus repair/test information. It will give a code but also explain the fault in English, as an example my PDC plays up the fault shows as PDC rear centre right sensor intermittent. 

Cost will be around £80 a diagnostic session at a Dealer will cost around £200 at todays labour costs

There are others that are BMW capable but not specific like Foxwell and I-carsoft personally I prefer the dedicated diagnostics. My old laptop  that I keep in the garage has several systems on it Volvo, Mercedes Star, BMW 1.4.0 BMW INPA/ISTA Toyota, VW VAS. My daughter tells people her dad is a car geek (but guess where she comes if there is a problem) Even if you end up talking to a garage you are talking from a position of knowledge/strength.

Dave

I'm lucky as I have (free) access to a professional level diagnostic machine only a 15 min drive away!! I'll pop it over this aft or tomorrow while I'm on leave and see what it says? Does the engine light have to be on out of interest or will it pick up fault anyway? I'm out of loop with modern cars, cut my teeth on old series land rovers and tractors so not really electronically minded (yet)

The specific programs will show 2 levels of Fault 1st Fault present/current and 2nd Fault not present which is Fault history/memory. With ISTA you will be able to clear all faults (Present and Memory) 

When a diagnostic is run it will show all faults remember some may be a a result of the fault others may be a symptom of the fault. I would run the Diagnostics note the faults, clear all faults shut down start the car and see what returns. The first fault will normally be the cause, check with engine off (battery fully charged) and engine running (live data)

Good luck 

Dave

Brilliant! thank you Dave you've been more than helpful 👍 

Steve