Member Since: 18 Sep 2006
Location: East Rand
Posts: 14
Gearbox Upchange Fault
Gearbox would not change up in drive last week, but only when headlights were switched on. Worked perfectly in command shift, and would hold 6th if switched back to D, kickdown OK but no subsequent upshift. All 100% OK during the day (with headlights off)
After further 5-10 mins faults occurred and logged as HDC, Special Functions and Lowered Suspension, but not Transmission!
I guess you will all point to battery voltage, but anyway took it to dealer last Friday and advised that lower sensor cable on rear diff was off, they re-connected, tested and pronounced all OK.
Of course, used it last night for first time with headlights and you guessed it - .
Anyone have any thoughts? If there is a lower diff sensor is there also an upper, or is this just twaddle and problem lies with battery?
Still great though!Mike
1st Feb 2007 8:38 pm
10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
strange.... does sound like a poor earth connection somewhere, possibly related to a wheel speed sensor (they're 'active' so require a +ve & -ve connection) Transmission fault wouldn't show as it was operating correctly without a wheel speed input i.e. in safe mode
it sounds very much like something was getting it's -ve connection through the headlight (or sidelight) circuit, thereby raising a fault DTC when the lights were on - do any of the lights look dimmer than the others?, including interior background illumination?
1st Feb 2007 9:14 pm
Mikely
Member Since: 18 Sep 2006
Location: East Rand
Posts: 14
All lights, including backlights look OK. I do, like many, have to replace brake light bulbs every 8-10 weeks!
I should add, that the gearbox will eventually change up, but at +/- 4300 rpm which is not very comforting. But at partial/normal throttle opening will just hold current gear, although will change down as one slows.
Many thanks TFC, any input for next dealer visit would be most helpful.Mike
1st Feb 2007 9:41 pm
10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
Sounds like there needs to be a 'wiggle test' on the wiring looms, with the lights switched on....
it's difficult to diagnose these type of faults with DTC's alone, sadly, not many tech's are taught or have experience at tracing physical connection faults, particularly when they affect multiple systems
i'd start with the engine bay earthing points then move on to the ones in both front footwells, after that, check the integrity of the body systems multipole connectors
Sounds like there needs to be a 'wiggle test' on the wiring looms, with the lights switched on....
it's difficult to diagnose these type of faults with DTC's alone, sadly, not many tech's are taught or have experience at tracing physical connection faults, particularly when they affect multiple systems
i'd start with the engine bay earthing points then move on to the ones in both front footwells, after that, check the integrity of the body systems multipole connectors
hope it helps You May Think I Said What You Thought I Said But What You Thought I Said I Did Not
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18th Feb 2007 8:27 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
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Posts: 72741
I've never had to change one yet in 75000kmHave a nice day!
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19th Feb 2007 10:18 am
Mikely
Member Since: 18 Sep 2006
Location: East Rand
Posts: 14
After 5 weeks of jiggleing (must go on diet or strictly come dancing) finally cracked the problem.
Basic problem was Rr R/H stop/tail bulb! Yes indeed, with side/headlights on, upper tail lights were out and no brake lights from pedal activation, however, high level brake light on permanently.
You may well ask, as I did, how does this affect gearbox? Well apparently brake light being on, signals ECU that one is braking and thus will not upchange gears!
Hats off to LRSA for advising what to look for.
Moral: Don't buy cr@p bulbs from emergency spares oultets!
TTFNMike
Member Since: 08 Dec 2006
Location: Europe
Posts: 36
Mikely wrote:
You may well ask, as I did, how does this affect gearbox? Well apparently brake light being on, signals ECU that one is braking and thus will not upchange gears!
So a bit of left-foot braking away from the lights then, it is... "There is a road from the eye to the heart that does not go through the brain" - G.K Chesterton
This evening my D3 has developed this fault. No WAY am I putting up with 5 weeks of loom wiggling! Car upshifts fine at 2500 into 2nd and 3rd but absolutely won't upshift to 4th, 5th or 6th unless I do it with command shift.
Coincidentally it has just had all the wheels off to have AT2s fitted and the fault was apparent within a couple of minutes of leaving the tyre centre. No evidence of brake bulbs being on so I'm betting on a brake or wheel speed sensor being dislodged when the wheels were done.
No faults coming up on the info centre at this point. Will be visiting the tyre centre and asking them to get the car up on the ramps for a visual check of all connectors near the wheels tomorrow. I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
Diagnosis...... (and you'll love this) is that the depot sent 3 x 255/60/18 and 1 x 255/55/18. I think "ooh sheeeet" was the expression the fitting centre manager used when he spotted it. To be fair, once I explained there appeared to be a wheel speed sensor problem he had it sussed in a matter of a couple of minutes.
He's got the correct tyre coming in on Monday so in the meantime I've put a spare Wrangler HP AW on and the transmission problem is no more. I'm going to push for a substantial discount on another 2 tyres for use as spares by way of apology for the potentially dangerous oversight I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
23rd Mar 2007 9:18 pm
10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
how can it be dangerous if you can't go more than 15mph?????
How? Firstly it wasn't limited to 15, it just wouldn't upshift from 3rd to 4th or higher without a prod from command shift. Secondly there 's the small matter of the load rating on a 55 tyre being too low. Bloke I dealt with went pale when he saw what had happened and was hugely apologetic. I'm just going to ask him for a price for two more when I see him on Monday and see if he twitches..... I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
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