overdrive kicks in and out below 50 mph
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Junior Member
Joined: Feb 2014
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From: Springfield, MO.
overdrive kicks in and out below 50 mph
I just purchased a 2004 XJ with 47,000 miles on the clock and am experiencing something odd. When driving and the car shifts into the final gear or convertor lock between 4o-50 mph., if you watch the tachometer, it jumps back and forth from 1500rpm to 1700 rpm until you ease off the throttle or accelerate a bit more in which case it smooths out. When checked for any codes, it shows none malfunctioning I figured since this car had so little miles, never wrecked or damaged in any way, that possibly the trans fluid may have gummed up and caused maybe the convertor lock up solenoid to malfunction. Changed fluid with correct replacement fluid, no difference. Had computer re-flashed, no difference. Had local transmission specialist replace solenoid, no difference. Now I`m really stumped. Thought maybe throttle positioning sensor might be bad, but again no codes showing even while driving and problem is occurring. Has anyone else experienced this problem or know the fix? What am I overlooking? Please Help.
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From: Crewe, England
I answered on your other post, but don't worry too much, it is a well-known syndrome caused, I suspect, by cr*p TCM software. ZF don't produce this, it is done by the user of the transmission, in this case Jaguar.
You'll find it disappears when the tranny fluid warms up, (about 10 miles of average motoring, quicker on a motorway/freeway).
You'll find it disappears when the tranny fluid warms up, (about 10 miles of average motoring, quicker on a motorway/freeway).
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Joined: Dec 2009
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From: Crewe, England
No ! I think the problem is sorted on the later gearboxes but I have yet to hear of a proper cure or even any statement as to why it occurs. Jaguar are silent on the matter for some peculiar reason known only to them. Sometimes I get really annoyed by Jaguar Cars, even though I love the cars.
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From: The beautiful Mornington Peninsula in OZ
I have an 03 XJ8 which has only done 63K miles in 11 years.
I have had a similar but much lesser problem which seems to have disappeared now perhaps because we are in high Summer.
During the first couple of miles when driving from cold I seemed to experience slight surging and the tacho was moving up and down but only about + or -100 RPM.
This effect soon disappeared but I have thought of a possible TPS fault also since applying more throttle seemed to stop the surging.
These TPS have two tracks 0 to 5v and 5 to 0v and they have to agree, also it is just a potentiometer which will wear.
People on here have dismantled failed a TPS and found the plastic degraded by heat and minute cracks in the track(s) and one could
imagine that could cause momentary loss of signal.
I have found a report on this forum where it was said that there was a cure for the surge but
he recommended "to just live with it" but did not say what the cure was!
I have had a similar but much lesser problem which seems to have disappeared now perhaps because we are in high Summer.
During the first couple of miles when driving from cold I seemed to experience slight surging and the tacho was moving up and down but only about + or -100 RPM.
This effect soon disappeared but I have thought of a possible TPS fault also since applying more throttle seemed to stop the surging.
These TPS have two tracks 0 to 5v and 5 to 0v and they have to agree, also it is just a potentiometer which will wear.
People on here have dismantled failed a TPS and found the plastic degraded by heat and minute cracks in the track(s) and one could
imagine that could cause momentary loss of signal.
I have found a report on this forum where it was said that there was a cure for the surge but
he recommended "to just live with it" but did not say what the cure was!
Last edited by meirion1; Feb 5, 2014 at 04:24 PM.
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Junior Member
Joined: Feb 2014
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From: Springfield, MO.
Thanks Everyone for your imput. My very first thought was the tps but when no codes showed up I couldn't justify it. Any and all thoughts welcome. I love this xj. It`s the sweetest one I`ve owned. I also have a 2007 XK COUPE, and a 1991 Lotus esprit. I wouldn't trade for any American cars and I have a few of them too.
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Joined: Dec 2009
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From: Crewe, England
I notice mine doing it more now when I am tootling around town on short journeys and the tranny fluid doesn't warm up. I just put the transmission into "4" for a while, and sometimes even "3" as it's all 30 mph limits here.
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