2004 X-Type 3.0 Automatic

My car wasn't starting, so AAA came out and put in a new battery (free because it was 33 months into a 36 month warranty, ka-ching for once!).

They tested once the new battery was in and it was showing 15 volts, which they said seemed right on the edge for suggesting the alternator was bad and could fry the battery.

Went to Advance Auto Parts today and got readings of 12.5 volts for the battery and for the charging system test got readings of 14.99 volts for no load and 14.84 volts for loaded. Again, right on the edge.

Do you all think this is a problem? What sort of voltage readings do you tend to get with the X-Type alternators?

The cheapest quote I've had for replacing the alternator is $362, which I'd rather not do if I don't need to! Of course, I'd also hate to be frying batteries left and right.

 

The full story of how the generator operates is as follows:

Vehicles With 2.0L, 2.5L or 3.0L Engines

The charging system consists of a 120 amp output generator and regulator assembly which generates current to supply the vehicle electrical system with electricity when the engine is running and maintain the battery in a charged condition.The generator is belt driven by the accessory drive belt.

When the engine is started, the generator begins to generate alternating current (AC) which is converted to direct current (DC) internally. The DC current and voltage is controlled by the voltage regulator, (located inside the generator), and then supplied to the battery through the main battery positive cable.

The generator is solidly mounted to the engine timing cover and is driven at 2.8 times the engine speed.Vehicles fitted with manual transmission have a one way clutch fitted to the drive pulley, which prevents torsional vibrations from the engine being transmitted to the generator.

The engine control module (ECM) can switch the voltage regulator between two voltages to optimize the charging of the battery.The low voltage regulator setting is 13.6 volts and the high voltage regulator setting is 15.3 volts, measured with the generator at 25°C (77°F) and charging at a rate of 5 amps. These values decrease with a rise in temperature or current flow.

The ECM determines the voltage setting of the voltage regulator. The high voltage setting is always selected by the ECM once the vehicle has started. The ECM determines the period of time that the high voltage setting is selected for.There are three different time periods selected by the ECM which is dependent upon the vehicle conditions when the vehicle is started:

The longest time period is selected if the ECM determines that the vehicle has been 'soaking' for sufficient time to allow the engine coolant temperature (ECT) and the intake air temperature (IAT) to fall within 3°C (37°F) of each other.

The intermediate time period is selected when the ECT and the IAT are below 5°C (41°F).

The shortest time period is the default time and is used to provide a short period of boost charge.

At the end of these time periods the voltage is always set to the low voltage setting to prevent the battery from being overcharged.The time periods are variable depending upon the temperature and the battery voltage.

The target voltage of the battery varies between 14 volts and 15 volts depending upon the ambient temperature and the vehicle operating conditions. Once this target voltage has been achieved, providing the vehicle has been operating for at least the shortest time period, the ECM will reduce the voltage regulator to the minimum setting of 13.6 volts.

 

Thanks astromorg. So you're saying it's fine then? That we all are getting 15 volts and that it drops after we've been driving for a little while?

 

Helpful and insightful Astromorg! I'm not sure if you know, but it can't hurt to ask. I have two questions.

Question, could the generator not operate properly and cause the ECM to think there is a problem with voltage correlation in the throttle or pedal sensor?

Question, could a faulty or poor A/C compressor cause complications with the generators ability to properly go through it's cycles or charge the battery properly?

 

The workshop manual is great sometimes

Free download, too.

 

No to both questions.

With respect to the throttle control, the description of operation in the shop manual in woefully inadequate. By schematic inspection, both position sensors receive the same excitation voltage from the ECM. This voltage is probably regulated to a value well below battery voltage (someone please help me out if you know what it is). Thus, minor changes in battery voltage should have no affect on the throttle position signals. The ECM will also provide a fault if battery voltage is too high.

 

Mark, that's almost right, but the voltages in the throttle control system are not the same! The voltages in the Accelerator Pedal Position Sensor (APP) are:

Sensor 1 Foot Off 0.97 v, Fully depressed 3.33 v

Sensor 2 Foot Off 3.97 v, Fully Depressed 0.84 v

That variation between them is also reflected in the throttle position sensor voltages:

TPS 1 voltage at idle = 0.74v / at full throttle = 3.97v.
TPS 2 voltage at idle = 1.65v / at full throttle = 4.2

There is also a compensation system built in to the ECU to take account of the AC compressor cutting in and out and voltage variations in the generator output and minimizing the noticeable effect of that.

Back to the standard generator output voltage question, I checked mine today. The car had been used for one 4 mile journey some three hours earlier so the engine was warm to the touch, but had no temperature gauge reading. On start up the charging voltage was 15.2v and stayed at that for six minutes before dropping to 13.4v, all in accordance with the design.

 

Damn! I keep getting a Throttle/Pedal Position sensor/switch A/B voltage correlation fault. If it sits over night and I turn the key the fault shows. If I turn it off then restart 60sec or so later it's fine. Two years ago I replace the throttle and it only has 12K on it. I just put a new OEM Jag Throttle in on Tuesday and I STILL get the code. The Pedal Assembly and Sensor were replaced a year ago and only have 6K of use. I city drive about 10miles round trip 5 days a week. Anyone have any ideas what else might be causing this aggravation?

 

I should also mention that if I drive around for a bit, or on the freeway, it will inevitably through the code again and go into Limp (P2135)

 

Have your battery fully tested (delta-t). Anything under about 88% capacity. replace the battery, The X is BRUTAL on batteries, and many unsolvable (insoluble for you English majors) problems are related to a battery that would last another three years in any other car!

 

Ugotmale, some thoughts! First, P2135 is not a code listed by Jaguar! The various codes that do apply to the throttle system give the causes, if not the throttle body and APP themselves, as faulty wiring - either open circuit, short circuit or short from signal level voltage to B+. The only other item mentioned is the throttle motor relay, but if that fails the throttle sets to a default value and idling is controlled by fuel injection intervention. Is that relevant to your situation?

Unfortunately the throttle relay is one of the permanently fixed relays in the glove box fuse panel, so replacement would require a new/used post 2004MY fuse panel!

 

Hey there lets see if I can post a comment here... I recently bought an x type at auction not running, did head gasket and got it running with alternator light on and waterpump leaking. Put advanced auto I believe rebuilt alternator as they required core and new waterpump and engine runs fantastic however my alternator light keeps blinking on and off intermittently. Not consistently either, intermittently. when light is off yea I got 14,5 volts at alt. and battery. I read 13 also after running for awhile, I assume battery charged again, but when light is on it is at 12.8 at alternator and battery. Posts here and ask.com and other post said change out cables, all of them, didn't change, light still comes on, I took the old ground cable that was bolted from terminal to body and added it with the new one to body and did not change , the other day I had this bright idea of taking that additional ground cvable to the trans, and it helped. The light does not come on with the frequency it did, but it still comes on and at this point I am lost. My last thought is take the pos. cable from battery to fuse block that came off and add that with the new one and see what happens cause that cable showed signs of the most heat even though I have still seen worse that that. That's what I have been saying, alternator is new and still have problem and actually never seen 15 volts. but people say they get it and I wonder if advance auto alternator regulator insid eis not strong enough, but I am not ready to pay 750 dollars for a jaguar alternator after just spending 300 dollars for battery cables.

 

Astromorg, the P2135 isn't the code the shop gave me just what my OBD tool listed. I've been trying to avoid going to the shop because it's been getting expensive, $115 a pop, but I've concluded it's what i'll have to do. I'm glad you mention throttle relay because I hadn't considered that. The more info I get here the better so i can have some semblance of know how when I chat with the shop tech. Hopefully the relay is not the issue. I dropped it off tonight to have it looked at so we'll see. I asked them to check the ECU and TCM for water ingress also. I also read on the forum that the Range Sensor could be a cause. Fingers crossed for good news.

Whydididodis, how old is the battery? A new one is about $180-$215 and seems like a better option than going with an OEM Alternator. Rockauto has some Alternator options around $200 also. Does the Advanced Auto one push enough amps, somewhere around 120?

 

Word back from the mechanic is - loosely translated into non-mechanic lingo - that the code is referencing low resistance at the throttle or throttle relay. So it's suspected that either the throttle relay is bad or the pins in the plug to the throttle are not allowing enough resistance and vibration is causing the signal to get lost. URGH! So I imagine if that is the case, I've been chasing this issue for the last 2yrs subsequently replacing the throttle body twice and the pedal assembly once when they likely weren't the issue. Damn car.

Question I have now is: What the hell are these pins that are being spoken of? I don't have the car so I can't go out and look at the throttle or the plug. The throttle is new so the pins must be in the plug.......? Can the pins or plug be fixed/replaced? Do I have to, somehow, replace the plug or entire wiring harness?

 

The first, and no-cost option, is to check the Black 4 way connector to the throttle body and the Black 2 way connector to the throttle motor. They should be bright and corrosion free and a spray of electrical cleaner may help.

If that makes no difference it is possible to byepass the throttle motor relay temporarily for diagnostic purposes!

First, remove Fuse 36, 20A in the Glove Box fuse panel to disconnect the relay from the ECU.Then rig a temporary wire from the output side of the Fuse 36 position and connect it to a 12v supply. That replicates the relay activated and may prove or disprove the relay's part i your problem.

The output side of the fuse position is the one with 0v with ignition on.

 

Good to know. Thanks for the feedback!

 

So I tracked down, or the shop tracked down, my fault issue. Seems the pins in the plug to the throttle body were loose and there was a poorly soldered wire they re-soldered. They also tightened the pins so they would connect better and I've driven about 300 miles, both city and highway, without an issue. I checked the plug and wire like it was suggested but I didn't see an issue, but I'm not a professional mechanic. I guess the Jag is very sensitive, like a woman. I should begin to refer to it as a "her". Seems, also, that I never needed to replace the throttle body or pedal sensor because the issue is related to the plug and wires.

The new thing, that didn't happen before, is the shifting is rough and seems to hesitate. I think this might be something related to a fluid change but I don't know. It doesn't miss, but it seems to have a surge of torque on the freeway at cruising speed and it feels like it doesn't know whether it wants to be in 5th, 4 high or 4 low around 40mph. Should I have the TCM re-flashed or disconnect and reconnect the negative on the battery? Or is this just the nature of the beat?

 

The other thing it is doing is it doesn't fire right up smoothly after a stop and restart. It acts like it isn't getting enough spark or there is too much gas in the combustion. It starts, but it's boggy. At first start it fires right up and spikes to like 1500 or 2000rpm and drops normally. If I restart it seems bogged down and it only jumps to like 1000 or so and levels off at about 700rpms. Is this an issue? It start everytime.

 

Sounds like there's a fault or.... maybe it's not yet relearned that you fixed it. Try a hard reset - which will clear the fuelling etc learned values. It'll run a bit rough when you restart so let it idle for at least 5 mins. Just drive normally and it'll sort itself out or if in a hurry look up the drive cycle.

In case there is still a fault, any that makes it hard for the PCM to run the engine can cause bad gear shifts till you fix the engine fault. Don't assume there's any fault at all with the trans! It just can't stand a naughty engine.

 

I have posted this in other thread, but I saw "Astromorg" and "Thermo" is very knowledge here; My X-Type (3rd one) got over heat and engine quit running, towed her home, check the spark plugs they all wet and have trait of brownish stuff, I drain the oil; Water came out before the gooey brown stuff followed out, trouble head gaskets. Remove the head gasket I saw in side cylinders full of water. After cleaned them up every things and put back together with new head gaskets,I replaced new radiator hose with thermostat and water pump, the engine cranked but still not start, I replace new ignition coils, new spark plugs, I scan the OBD gave twelve codes, some of them duplicated: P0122, P0182, P0193. P0222, P1108, P1532 (2X), P1549 (2X), P1603 (2X). I'm OK with mechanic but am not with electric nor electronic, can you tell me what are these codes? How to test them? Could it be ECM?