Hi all,

Just purchased a 2002 X-Type 3.0 automatic. Car wouldn't start without a jump but was in decent shape and a good deal. The car is having an issue with charging. It will start but then stall/die after a while. Replaced battery as existing one tested bad. Replaced alternator. Still no luck. With a fully charged battery it starts no problem, but a voltmeter shows the battery dropping from 12-14v down to 8v at which point the car stalls.

I've tested a few things and am at a loss at this point:
1. Removed the new alternator and had it tested. It tested good, I have the test results if any of the values are of importance, but it shows the alternator putting out around 15V.
2. Tested resistence from alternator to battery - nearly zero. Tested resistence from alternator to ground - nearly zero
3. Checked serpentine belt, it appears to be installed properly, reasonably tight, and without any wear. Hear no slippage when running.
4. Reset the ECU.
5. Tested voltage while running. Can easily see the voltage dropping while the car is running. 14V at first, down to 8V when the car stalls.
6. While it is running, it is throwing a few OBD codes. Several seem to be caused by the low voltage. C1145, P1793, P1000, P1603, P1647

What else should I try?

 

When the engine is idling, what is the voltage across the battery terminals?

Is the alternator the correct one for the vehicle? It's always better in my opinion to take the one in the vehicle that failed to an automotive electrical shop for overhaul. Some of the 'rebuilt' and 'remanufactured' alternators and starters sometimes don't function correctly when installed. This is especially true of the voltage regulator/rectifier pack.

 

Dave, humor me with this test. What I want you to do is to put the battery on the charger and get it up to 100%. Next, I want you to start the car (engine cold), and as soon as you can, turn on everything electrical that you can. Hopefully the car willl run for a few minutes under this condition. If need be, sit in the drivers seat and attempt to keep the car running as long as you can.

If you can make the car run for a minute or two in this state, I want you to now cup your hand OVER!!!! (DO NOT TOUCH!!!!!!!) the battery terminals. Is one hot (atleast significantly warmer than the other)? If so, you have a bad battery cable. This is a common issue with the X-Type and your problems seem to point to this.

If both of these terminals seem to be at the same temperature, then the next check you want to do is to access the Engine Control Computer (ECM/ECU). You will see an orange wire with a green stripe on pin 65 (look on the connector (may need to remove it), there will be numbers indicating where Pin 65 is). Insert a sewing pin along the wire and then connect the red lead to the pin and the black lead to the body of the car (any bare metal surface). With the engine running and the voltage starting to drop (can use the interior lights to see them start to dim), is the voltage up at 13 VDC (or whatever the relative voltage of the car is)? If yes, you then either have a major short in the car (unlikely as you would have a fire ball somewhere, at a minimum a wire glowing white hot and would appear like a light bulb in an unusual spot) or the wire between the ECU and the alternator has an issue (unlikely, but possible).

Hope this helps.

 

 

Yes, attach red to the inserted needle, black to chassis ground point of a multimeter.

 

Dave, with the wire inside the plug, you cannot access the bare copper to get a reading. So, what you are dong is sliding a normal sewing pin/needle down along side the wire. This will allow the point of the pin to touch the copper and since the pin is metal, it will become energized too, giving you a point outside the connector to be able to attach your multimeter to and see the voltage. What this check is doing is if you see a high voltage (near what the battery is), then this is telling me that you have either a very large current draw or there is a break in the wiring between the ECU and the alternator (leading to the alternator not outputting anything). If the voltage on the pin is very low, then that tells me the ECU has the issue.

The sewing pin will slide along the wire going to Pin 65 in the connector. it is an old mechanics trick so you don't have to damage the wiring insulation. Damaging the insulation will result in more problems in the future that if you can avoid, you want to do.

 

Thanks Thermo, you were on the right track. There were two problems. The 4-pin control wires going into the alternator were not receiving good signals, they were corroded and loose. Signals at the computer were looking pretty good, but then at the alternator itself they were going crazy.

Second problem, probably due to the first, the alternator was dead. We cleaned up the wires, swapped alternator, and all is good!

 

Dave, good to hear that things are like they should be. Stuff like this happens when the plug goes not make a good seal. Adding current going through the connection and things go south that much faster.

 

Well my previous post was premature. I am still not seeing any output from the alternator. This is based on a clamp meter on the wire from the alternator to the starter - shows 0 amps. Can anyone clarify what the signals on the alternator control wires should look like? EN49-2 green red Iabelled B+. EN49-1 red-green labelled Charge, EN49-3 orange-green labelled FIeld, and EN49-4 blue labelled generator load. I don't particularly care if the battery light in the instrument cluster stays on, I just want the alternator to function.

 

Post #6? =

https://www.jaguarforums.com/forum/x...working-57277/

 

i changed alternader and power wire from alternader to the battery changed all pullys and tensioner

 

after that the problem was solved