Harry365
Member Since: 25 Aug 2018
Location: Lincoln
Posts: 373
  
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| Stalling at low speeds, very rough idle/stall, rev hunting |
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Morning all, another fun one to figure out. Quite a bit of back story to what I believe is related to the final outcome.
A couple of months ago, towing 3 tonnes from UK to Croatia, I had one instance of a rough gear change from 4th to 3rd. Holding about 55mph and a very long hill. It banged into gear which caused gearbox fault. Drove relatively fine but TC was unlocked at any speed and engine fan increased - gearbox overheat. Restart car - "fixed".
Fastforward a few weeks, same situation happened towing on the A1 holding 60mph on Grantham hill. All fine after that until -
1 week ago, I started noticing a very slight rev hunt at low speeds, high gear. More noticeable in cruise control.
Yesterday - running in low box, I experienced engine stall when coming to a stop. It happened several times, also twice when selecting reverse and once when simply lifting off the accelerator. Went into what i call extreme limp mode. Had to clear faults while engine running to get home.
On the drive, engine will lose power and drop to 250-400rpm and or/stall.
Catch-all warning light, amber brake, F on gear selection.
Fault codes after clear and fault trigger:
Engine -
P151C-00 - Idle speed control - RPM higher than expected (2A)
P0501-00 - Vehicle speed sensor A range/performance (28)
P0191-24 - Fuel rail pressure sensor range/performance - general signal failure - signal stays high (68)
Parking Aid -
B1B46-96 - Rear right inner sensor - component failure - internal failure (2B)
Veh Dynamic -
U0401-68 - Invalid data received from engine control module/powertrain control module - algo based failure (2B)
Transmission
U2023-86 - Control module network signal calibration data - bus signal/message failure - signal is invalid (AB)
What I have done so far
Inspect module immediately behind battery, contacts very clean, all dry. Opened up the module, perfectly clean inside.
Air filter check, MAF clean.
What I am going to do
Check/clean big connector in rear wheel arch. check cables leading up to this
Check vehicle speed sensors and graph outputs
Change fuel filter and check LPFP pressure
Check gearbox oil level
Calibrate steering and ride height.
Will report back.
I think there could be a couple of things going on, dodgy auto box not helping things (annoying because it was refurbed 1.5 years or 20,000 miles ago) but most likely the issue is speed sensors from what I have been reading.
Can anyone add any thoughts/suggestions to the above?
Many thanks
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 20th Jun 2023 11:07 am |
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