Member Since: 03 May 2024
Location: Shrewsbury
Posts: 8
P0915 - what would cause the gearbox to Clunk between P/N/D?
Hi,
Chasing around P0915 "Gearshift Position - circuit range/performance".
I can see it comes up here and there, but nothing concrete in terms of solution, although all of the symptoms are described in other posts, there isn't a resolution. These include U0402 and a selection of faults derived from invalid data from the TCM. (but I don't think its the TCM at fault)
Test Gear = Icarsoft LR3
Brake Switch = OK (changed anyway, but registering correctly in live data)
Battery = OK (meter tested and ECU recognises as good)
TCM Module = Dry, no corrosion (haven't removed, but will at some point if needs be)
This fault occurs when moving from P/N/D etc, sometimes when static. Never when driving.
99% of the time, the gearbox is smooth between selections of P/N/D.
1% of the time AND coinciding with P0915, the gearbox "Clunks" between P/N/D. Going into P, the selector will be locked into place until fault cleared or ignition cycled.
When P0915 occurs and the selector is on D, the TCM Live Data Reads:
Gear Commanded: Invalid/unknown
Transmission Gear Engaged: Invalid/unknown
On clearing the fault, the Live Data shows the 1st gear Commanded and Selected - as you would expect.
Whilst the symptoms are "mechanical" I feel the cause is "electrical", because the fault can be cleared and the P/N/D shifting is immediately smooth again.
This is where I need some expert advice from someone that really knows the cars as I am NO mechanic, but after £360 at a LR specialist, the fault is exactly the same.
1. What "thing" would need to stop working in an automatic LR4 transmission for it to start clunking between P/N/D?
2. Why would this "thing" stop working and what does clearing the TCM Module fault do in order to rectify the situation?
3. Could it be the gear position sensor?
Any help sincerely appreciated. I have tried to capture a live data recording at the time of the problem, but there is nothing that sticks out at all.
I will 100% come back with what has happened... I can see that this is frustrating when people don't...
Cheers
G
3rd May 2024 6:12 pm
GBL78
Member Since: 03 May 2024
Location: Shrewsbury
Posts: 8
Removed headlight and improved GND connections, also on connections next to fusebox/battery. Both showed signs of corrosion, but nothing too bad.
Removed battery and checked ECU for water ingress etc. Didn't take apart but connectors were clean and the casing was fine, no signs of water nearby.
Took for a drive and fault occurred.
I have played all my cards!
4th May 2024 1:13 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4698
Try transfer case recalibration!yµ (idµ - eAµ) ψ=mψ
4th May 2024 3:45 pm
GBL78
Member Since: 03 May 2024
Location: Shrewsbury
Posts: 8
Thanks. Done. Will report back.
During the period that the car has this fault:
Actuator Supply Voltage 3.09V
Normal Running:
Actuator Supply Voltage 14.5V
But I don't know if this is a purposeful reduction in V or if its a loose cable is the actual cause of the fault.
Consulted the wiring diagram today and checked all wiring + earths that I could get to. Unfortunately the "good stuff" is on the transmission and out of my reach/expertise.
Cheers
G
4th May 2024 7:43 pm
GBL78
Member Since: 03 May 2024
Location: Shrewsbury
Posts: 8
Transfer Case Recalibration (reset) did nothing. You can tell "something" has happened, but the fault is just as likely/often.
5th May 2024 6:36 pm
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6275
might be of help
Click image to enlarge
5th May 2024 6:56 pm
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6275
might as well be electrical issues in gear selector itself, have you taken it apart to check for damage on circuitboards?
or have you checked transfer case solenoid for operation? I had general gearbox fault due to leak which was getting into solenoids connectro completely confusing whole system
Greg
5th May 2024 6:59 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4698
The issue could be simple (shift cable adjuster sticking) or not so simple (TCM plug/wiring or mechatronic unit/plug/wiring)
Are you scanning all modules, and are there any other faults logged in them?yµ (idµ - eAµ) ψ=mψ
5th May 2024 7:09 pm
GBL78
Member Since: 03 May 2024
Location: Shrewsbury
Posts: 8
grzesiul wrote:
might as well be electrical issues in gear selector itself, have you taken it apart to check for damage on circuitboards?
or have you checked transfer case solenoid for operation? I had general gearbox fault due to leak which was getting into solenoids connectro completely confusing whole system
Greg
Hi Greg, Cool Name...
Thanks for the document, I will work it through.
With regards to the solenoid, I don't know how to check its working. Should I remove it? (its the part in pic attached right?)
Out of interest... if the solenoid stopped working, would the gearbox bump between P/N/D? This only happens when the fault occurs, all other times its very smooth.
I can tell why garage was reluctant to get into this...! (I have learnt a lot... about cars...)
Cheers
G
5th May 2024 10:18 pm
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6275
Hey,
Soleniodshould be working fine if transfer case goes to low range with no issues. Just mentioned it as its connector flooded in oil caused major gearbox faults on mine two years back.
Also I ma not sure but I guess your D4 being 2010 is 6 speed?
If it was 8 speed which i doubt i could sent you my old gear shifter module to help in troubleshooting if it not shifter issue.
I would defo look into mentioned shifter cable as well as shifter body.
Rgds
Greg
6th May 2024 9:25 am
GBL78
Member Since: 03 May 2024
Location: Shrewsbury
Posts: 8
Hi Greg,
Yes, 6 speed, thanks for the offer - very kind. It does go into hi/lo with no trouble. It drives very well (until this fault occurs).
The shifter is something I can look at today. Will read up on that.
Will come back to PROFSR when I have a list of the faults.
Cheers
Greg
6th May 2024 10:02 am
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6275
if drives well i bet it issomething with shifter while switching gears
good luck
Greg
6th May 2024 10:35 am
GBL78
Member Since: 03 May 2024
Location: Shrewsbury
Posts: 8
I removed the gear selector in the console. It was very dirty, but I couldn't see anything that I could usefully "do" to it. The "gear commanded" on the ECU does read correctly.
I measured the resistance of the transfer box motor, it is so completely wrong, that it must be me measuring it badly.
Really don't know what to do next as the garage has said just to keep driving it until it gets worse. But that doesnt seem like a good solution...
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