HELP, THIS IS URGENT.

Hello,

Just had a new gearbox put in my old 2001 X308. Gearbox ZF 5 HP 24.

Now, the engine will start but will only idle, it does not respond to the accelerator pedal.

The gerbox shop, who does not touch engines, gets the following 3 codes. They do have a test book of some sort ...

P1121 Pedal position sensor A Circuit Range / Performance

P1000 OBD System Rediness test not complete

P 1647 Linear O2 Sensor Control chip bank 1

Can someone interpret this to me in ordinary language ?
Is it enough to just reset the car computer ? How ?
Or has something else to be done ?

Please help, I am stuck in the middle of nowhere in the south weat of France.

Thank you,
Takeo.

 

Hard reset: Remove negative cable from battery and touch to positive cable for about 20 sec. You may lose radio programming.

 

Please check TSB 303-58.

bob

 

If I understand this Technical Service Bulletin, the transmission shop has either cut the wires or disconnected the connectors . . You don't need to worry about P1000 or P1647 for now.

Bob, is that right? It was running without the gold connectors (?)

 

The GOLD connectors do not oxidize like the tin plated terminals. You can clean the connector and it should work for a while but the gold terminals are a long term fix.

Check ALL the throttle connectors!!!!

Also check the large engine harness connector behind the throttle. It has a long bolt to hold the halves together. Maybe it was disconnected and a pin damaged??

bob

 

Thank you all for your most interesting replies.

All has been tried, still no dice. Car idles nicely, but accelerator pedal still does not respond.

Gearbox shop has no solution and all Jag garages here, up to 200 miles away from where I live are all on a
skeleton crew until September ...

What we seem to need is the appropriate software to properly reset eco tau and other computer relates things.

I paid 3500 Euro for box repair but car is still going nowhere.

*swearword*

 

What about the actual pedal position sensor have you checked that?

 

Did the workshop remove the flex plate? I'm not sure if the flex plate can be fitted wrong but maybe, if possible, it is in the wrong position to the other sensors ans the engine is in a 'fail safe' setting?

 

Dear Daim,

The workshop DID NOT (they assured me) touch anything except for the gearbox and oil lines. There was absolutely no point at all to touch the engine itself. They only dropped the gearbox, replaced the trorque converter with a new one, replaced all the innards of the gearbox with new components and put the gearbox back, reconnected the oil lines to the oil cooler.
They probably did disconnect the battery for a few days and it seems to be known that if one disconnects the battery for some time, when reconnecting it, all sorts of funny computer gremlins may appear.
My only problem is code P1120 = TSP = Throttle Position Signal.
I think only a reset is necessary by using a test book that has he appropriate engine software for the X308.

Regards,

Takeo.

 

I have disconnected the battery on various Jags for up to two weeks without negative effects, but it's wise to be sure the battery is charged. Have you cleaned the connections to the throttle body?

 

My local shop had an XK8 that only idles, and it was the TPS.

 

Hi Robert, how did they solve the TPS problem ?

My TPS problem arose after they pulled the gearbox and put a new one in, engine was never touched, so i am sur it is a computer-related problem.

Thanks.

 

I would not be certain it's a computer problem. They were certainly working in the throttle body area while changing the transmission. That's why I suggested cleaning the connections.

 

Hello,

The gearbox shop assured e they have not touched the throttle body at all. I believe them.

Problem is that they are about 100 miles from where I live and I do not have another car for the moment. But I might thy to go there one way or another and see what I can do myself,

BTW, How to clean thos contacts ? I am not sure if a wire brush would be a good idea.

Thanks.

Takeo.

 

Hello,

I just read in the workshop manual that the engine went into "Engine Failsafe Mode" after typing in P1121. Throttle does not respond ...

Does anyone know how to get out of that ? Has that something to do with the funny thing left of the gear stick ? Limp home mode ?

Thanks,

Takeo.

 

Oh well, no luck here in France.
Tomorrow I will rent a trailer, go get the XJ from the gearboys shop and park it till next month when I can take it to a Jag garage
after their yearly August vacation.

GRRR.

Takeo.

PS. Has anyone an idea abvout what I can try myself on my car ?

Thanks.

 

Have you carried out a search on this fault code? P0121 - Because the car has notified you of this fault and will not respond, it isn't a software issue, it's mechanical as others have suggested. I would suggest getting as much knowledge together on it so you know what we are suggesting.

As your car is a 2001 it's equipped with the AJ27 throttle body, this has 2 sensors on it and it's a true 'fly by wire' throttle, meaning the sensors control the throttle plate, not the cable attached to the pedal. If there is a fault with either of these sensors, the car will log a code and go into 'failsafe' mode, you will at least be able to load it onto a trailer as it defaults and will run. (Assuming the new trans is good)
To correct the fault Motorcarman has suggested a fix but as it's a 2001 it should already have the upgraded connector pins.
So, we move onto the number 2 fix and this is a replacement throttlebody £1000 from Jaguar new, around £200 used, OR fit a replacement TPS sensor £80. These can be bought from this link below, but you will need to do some research on fitting it and setting it up. It isn't a case of simply bolting on, there is a very fine adjustment required while the engine runs to achieve idle to 550/600rpm.
Throttle Position Sensor (TPS) for Throttle Bodies C2A1444 and C2A1445 Fault Code P0121 198500 3250 | Jaguar XK8 and XKR Parts and Accessories

 

Thank you all !

0700 HRS this morning I got a rented trailer on the road and set off for a 75 mile drive to the box shop. After some pointless discussion, I loaded the X308 on the trailer
and brought it home to my home garage.

When I started it up at the box shop my display lit up like a Xmas tree. The engine started immediately but I had a rough idle between 1000 and 2000 RPM instead of the normal 600 RPM.

In 2nd gear the car drove right up the trailer ramps. i drove it back off, tried all gears, all worked but only in idle. No throttle pedal response at all.

Now my display lost the orange engine symbol but I get a mention "gearbox fault" alternating with " "engine failsafe mode".

Up to the moment that gearbox gave up while driving, all was working well. It just broke down under way.

I am now thinking the gearbox guys messed with wiring by accident. I will have a look at it tomorrow. Too tired now. I will keep you posted.

Thanks very much all.

Takeo.

 

Oh Kay ....

To the attention of M. RJ237.

Dear Jag friend and Jag electronics connoisseur !

My gearbox repair shop, ATD in Peujard, in the Gironde dept. In the Southwest of France, near Bordeaux, may be good gearbox repairmen, but that is where it stops !

When they told me that the X308 would not have any accelerator response, after putting the new gearbox in, I took your HARD RESET hint seriously and asked them to do that.

They assured me later they had done it but to no avail. Bunch of @@!#$%^&$#@@ LIARS !

After having brought my Jag home two days ago ($ 200 trailer rental + unpleasant and scary 80 miles @ 60-70 Km/hr between semis that doing 80-90, I took, this morning, a look at my Jag myself.

Checked all wire connections and finally did a HARD RESET myself, using my Omega Seamaster chronograph wristwatch for the exact 20 seconds as you suggested.

A bit nervous, I started the engine, depressed the acclerator pedal and ... VROOOOM. As in it went VAVAVOOM (old movie).

Engine idled a very sweet 600 RPM, letting me hear the sweetest V8 bom-bom-bom-bom sound from the exhaust.

Put her in D, NO jerk.

Put her in R, NO jerk.

Back in D, let the brake pedal go, bit of right pedal and she drove right off. I DID NOT BELIEVE MY FRIGGING SELF !

So I took her for a spin, about 4 clicks, PERFECT !

NOW ... the BIG question is: WHAT DID I DO except following the precious hint that member RJ237 gave me ?

I have a PhD in nuclear physics. (+ two post-doctorates). A good friend of mine has a PhD in mechanical engineering. I drove upt to his place and he could not believe what I told him.

So we sat down and asked ourselves what the HARD RESET actually did.

The only conclusion we could come up with is that the HARD RESET causes some sort of "memory dump" in the car's computer system, clearing all memory-related condensators and
related computer chips. (We are not sure, however, that this will be a permanent solution but it WORKS !). But HOW is still a question, I need to look that up, I have a vague idea it could
have someting to do with ion exchange or something like that. Touching the + of a battery with the - lead ? Very strange indeed !

RJ237 KNOWS what he is talking about and I am VERY grateful for his hint.

To all who read this, please keep that in mind !

RJ, I OWE YOU ! You saved me something like $ (a lot) for not having to visit a Jag garage 120 clicks away on a trailer or car transport truck.

If you ever come to France I will buy you the nicest meal ever in Angouleme with the best Bordeaux wine and a good genuine Cognac after.

Again, THANK YOU !

Yours sincerely,

Masamune Takeo.

 

Pleased to hear it's running again. I'm not a computer expert, more old school mechanic and research chemist. To the best of my understanding a hard reset causes the the ECU to communicate with the other modules, reverting to factory settings. This should be a permanent solution.