Ok I went to start my 2005 xj8 and nothing . the car unlocks and locks. The interior lights heated seats and power seats work. The windows headlights radio don't work. I have 12 volts on the battery. The car was working fine the day before I checked all the fuses they all where good. I had someone come over to check out the car with a code reader. The code can p1638. This was a pretty cold day. Any help would be greatly appreciated

 

P1638 indicates a problem with the linkage through the CAN network to the ECM (Electronic Control Module) and the INSTM (at the moment I'd guess that denotes the instrument cluster module but I'm not sure).

The VERY FIRST test before you go wandering around spending a lot of money is to test that the battery is fully charged. With everything off a multimeter should show a static reading the neighborhood of 12.75 to 12.9v not just 12v or even 12.5v. With all of the electronics these cars are very sensitive to voltage especially when it's cold and battery chemistry is reduced.


If it reads lower that I posted first give it a good long trickle charge at low amps, not a jump start fast charge unless you really want to do some damage just for the fun of it. I've got several hanging around for my motorcycles and various vehicles and I don't think I've ever spent more than $30 for one. Walmart sells a decent line of Schumacher's for not much money.

If that isn't the problem report back and one of the online tech's who really understand the various modules will help. You might want to go to the download section and grab some XJ8 service files that cover the 2004+ years including an electrical schematic that shows where the umpteen ground points are as you may need it.

 

Hi sreed08,

Welcome to the Jaguar Forums!

I'm sorry to hear that you're having trouble with your X350. As RDMinor has already stated, your battery is the primary suspect, especially since it was a cold day when you experienced the no-start condition. The most important measurement of battery voltage is the voltage while cranking the engine. If it dips much below 11V, the Engine Control Module (ECM) will not trigger the ignition to fire. Some digital meters react too slowly to show just how low the battery voltage may be sagging so you may do better with an older analog meter.

Also, a generic OBDII scanner cannot read the proprietary Jaguar codes, of which there are many. If your battery voltage seems to be holding above 12V while cranking, your next step may be to have the codes read by a dealer or a good independent with the dealer-level computer-based diagnostic system, such as System Driven Diagnostics (SDD).

Please note that the entire Jaguar X350 Workshop Manual is available for free download in six sections from the 'HOW TO' quick links thread near the top of the home page of this X350 forum. The 2005 X350 Electrical Guide is available for download here:

http://www.jagrepair.com/images/Elec...al%20Guide.pdf


Also, since we're a friendly bunch around here, please visit the New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum and post an introduction so we can give you a proper welcome and learn something about you and your Jag.

Cheers,

Don

 

+1 on battery check, not just voltage but the crank amperage capacity needs to be good too.

 

Thanks a lot for all the info soon as this rain stops I will be back at it.

 

Ok changed the battery and still nothing. I needed up holding the unlock button on the key to see if the windows would go down and yes they did but now they won't go back up smdh. Maybe the car is in security mode or something. I'm lost now. I checked all the fuses and all are good I checked the starter that's good to. Nav screen still saying ignition off.

 

What volts on new batt? They often come part flat.

 

I would disconnect and shine up the two earth grounds in the boot to begin with.

 

Batt volts was 12.8

 

That's very healthy.

 

Did you try hard reset? check fuse box for blown fuses?

 

ok I am confused, do you mean it cranks? but wont start? these are too different things, if its turning over then battery is fine. You need spark, air, and fuel to start. First thing is to check fuel pressure,55-60psi,if you have healthy fuel, then next check the spark, pull a coil and use a spark reader, turn the engine over you should see a spark, if you don't , then if you have a noid light then disconnect the coil connect the noid to the coil connecting harness and use the noid to determine if the current is going to the coil. If you have current and spark then check the signal to the vvt solenoids, they should switch from bank to bank as the engine turns over. If the car wont engage the starter, do a test loop bypass to the solenoid to see the voltage to the starter...If you do a direct voltage app to starter you should hear it engage, if not starter is bad. I haven't seen many jaguars come to shop with starter issues, but if you have tested good on all the above mentioned ,then try a hard reset but disconnecting the neg terminal to battery for 45 min. If that doesn't work, then I hope you have a good enough scanner to test all live signals from the ecu. Again keep us posted we all are hear to help in any capacity.

 

OK car does not crank. I jumped the starter out and it works. I checked all fuses. Under hood cabin and trunk. None of the lights on the dash come on. I already did the reset and nothing. Well the radio started working after . but the windows and dash still doesn't work. The security light doesn't flash either. And like I said the windows are down and can't get them to go up. I did get the sunroof to close by turning the key to lock position.

 

From the symptoms that you described, it acts like there's a poor earth ground somewhere. Try checking for continuity between the negative post of the battery (leave the negative battery terminal connected), and an earth ground in the bonnet area. It's best to disconnect the positive terminal from the battery before performing this check.

 

I will try that when I get home.

 

OK still doesn't do anything. I'm ready to sell lol.

 

You have a P1638 code - since the battery checks and starter too - you have to perform "pin-point" tests to get to the bottom of the Code issue.

 

My wife's 2005 XJ8L just pulled the same stunt on her. Wouldn't start, all accessories operable, battery charged. Didn't check for a code on the car but to get it home I had to try and shift the transmission from Park in order to winch it onto the trailer. Long story short, the shift cable or mechanism has let go somewhere and the transmission was actually in reverse so the neutral safety switch was interrupting the starter circuit. I was able to reach under the car and manually activate the shift lever arm on the side of the transmission to Park where I was able to start the car and then later to neutral so it could be winched on the trailer. (It helps to have owned a few Edsels with the Teletouch Shifter. When they conk out, you get pretty good at this!) It would not allow me to engage drive from under the car or I could have driven it home. The DTC 1628 on my iPod app translates as Module Ignition Supply Input Malfunction so I don't know if the car might interpret a neutral safety switch in the wrong position related to the shift lever as that or not. I only got on to this as my helper was near the rear bumper and the backup beeper was going off even though the shifter was in Park. Just an idea. Wish you luck!

 

The shifter works. I'm trying to sell the car now. I have it on Craigslist. I will give it a couple days on there. Then I will take it to a shop . thanks for all the help

 

Hi sreed08,

I'm sorry you are frustrated with your car, but how much do you expect someone to pay for a Jaguar that won't start? In our area, Jagaurs that won't start bring a small fraction of what they would bring if they were running. You stand to lose far more by selling it in this condition than the cost of having a professional mechanic diagnose and repair the problem.

Please keep us informed.

Cheers,

Don