'98 XJ8 VDP, 139xxx miles.

Traveled about 150 miles on the highway today with A/C on, about 85 degree weather, some rain. Near the end of the trip, got a Tramission Fault error message, and car seemed to shift/slow down a bit. Then my wiper and turn signals no longer functioned. Luckily I was right near my exit so got off and shut the car down at the first place I could safely park. Let it sit a few moments, it started right up but seemed to accelerate in a jerky fashion, and a number of error messages came up, including Transmission Fault, Low Coolant, ABS Fault, Stability Control Fail, Traction Control Fail, etc. Then the Check Engine light came on so I pulled over onto a side street and shut the car off. Tried to start it a few minutes later, normal System Check procedure messages/lights came on, but only a single click and whirrrr sound, no crank, no start. Only error message now was Low Coolant. Checked under hood, the coolant sensor was hanging loose below the reservoir, cracked at the base of the orange/brown tubular shaft. The reservoir was full. Tried to reinstall the sensor, no luck. I think it is toast at this point.

Disconnected the battery for a few moments hoping to reset the system, no success.

Questions:

1 - Could a low coolant fault prevent the car from starting? If so, is there a way to bypass the sensor, or do I just need to replace it as a first order of business?

2- Could this be one or more fuses going bad? Which ones should I check? Looked through my manual, none appeared as an obvious ones to check.

FYI, I had the transmission repaired/rebuilt about two years ago. Did secondary tensioners about nine months ago. Recent oil change, oil level good, coolant level good, nearly full tank of 92 octane gas. Temperature gauge reads right in the middle, has never gone above (hot) in the nearly three years I have had this car. New battery about 15 months ago.

Any help appreciated as I am at a friends house for the weekend with my car about a mile down the road (pushed and parked safely on another friends driveway) with no way to get home!

Thanks very much for any assistance.

 

The coolant level sensor will have no affect on the car other than the instrument panel message. You can connect the two leads at the sensor connector to eliminate that.

Appears that you have read the OBDII codes. Please post them. Have you looked the codes up on the internet? Assuming you do not carry a copy of JTIS around with you.

The click and whirrr sounds like low battery voltage or a loose connection of the B+ or ground cables from the battery to the starter. Low voltage could create all sorts of codes.

 

A bad battery can cause all kinds of problems in these cars - I had one due similar things.

The fact that it happened after a long drive may point to a failing alternator that was not able to keep up with the electrical demands -- and you were slowly discharging the battery.


If you have an older battery in the car - I would first replace it - and see what happens. If the car starts right up and runs - you then check out the charging system. If the battery is newer - you are going to have to charge it up and go from that point. I like to charge the battery disconnected from the car.

Batteries are strange -- especially in very hot weather. I had to replace a 15 month old battery in my Lexus last week. Started the car fine -- drove an hour -- dead.

 

Thanks for the info. Going to see if I can get the car started with a jump. If so I will bring it to the Walmart in my friends neighborhood (I bought my battery at my local Walmart) to have them test the battery and charging system. The battery is still under warranty, so if it is the culprit, they should be able to replace it free.

BTW, don't have a code reader, should probably get one. I was just relaying the error messages that came up on the console.

 

You may be able to jump the car and get it started -- but if the charging system is not working you will quickly drain the battery. If the battery is good it may have recovered enough to start the car - but this will quickly strand you.

Also - make sure you have the correct battery. Its a large battery with the vent. I have seen people put the wrong battery in the cars to save a few dollars - you want the vent! And the CCA

 

Car started up after cranking slowly for a few seconds. Drove it to nearby Advance Auto, where they tested the battery and charging system. Battery tested as follows:

Voltage: 12.05u
Measured: 766 CCA
Rated 850 CCA
Temperature: 88*F
Battery is good but low on charge. Check for causes of low charge:
-charging system
-alternator belt
-cables and connections

We then tested the Starter as follows:
Voltage: 10.89u
Amps: 0.0A
Time 1.17s

Then the Charging System as follows:
No Voltage
Charging system problem
Check belts, connections and grounds.
Alternator service recommended if connections are ok.

Had to then jump start it to drive it about two miles back to my friends house. About halfway there, the error messages began appearing on the console as yesterday. Batter light came on as I pulled into the driveway, and the car stalled.

Charging the battery now, a local mechanic friend is coming by to check it out.

How hard is it to get at the belts/connections/alternator and replace if necessary?

Thanks again.

 

Alternators in general have become quite trouble free -- I have never touched any in my Jaguars and you rarely see them mentioned.

I would bet they are not cheap - years ago you could always find a rebuilder - but depending on your location this may not be possible.

Just make sure to look at the belt placement before you take it off and don't over stress the tensioner (some don't like this when they get old)


Wish I could be more help.

 

One of our sponsors (Ken at Motorcars LTD) has a salvaged unit for $200, and he can ship overnight if you call him tomorrow. He guarantees his products.

That is, of course, you can't find a rebuilt unit somewhere closeby.

 

While I have never understood why, there have been several reports of non-OEM alternators causing problems but bet there is a 'fits' alternator an any AP store open today. The belt routing is available in the attachment.

 

Best I can tell the current alternator is the factory original. At least I know neither I nor previous owner changed it (that covers the last eight years or so).

A mechanic friend tested the charging system and showed me that the alternator was putting out much lower voltage that it ought to be, so the battery was being run down and not recharging.

Was able to source a replacement unit (Nippon Denso) locally, will pickup 8AM tomorrow. Luckily, both my friend's son and another local friend with extensive car repair experience are coming tomorrow to help me get this repaired.

I've checked online for the alternator removal and replacement procedure. Any opinions on whether its easier to remove from the top (removing twin fan and motor assembly from behind radiator) or from the bottom (removing oil filter) of the engine bay? Any particular tool(s) and procedure(s) to handle tensioners and remove the belt? Tips and suggestions welcome.

 

Please check the Terminal Post (LNC1380AA) on the false bulkhead in the engine compartment (Right side where the starter/alternator cable connects to the main power wire near the ECM/TCM box). These have a habit of melting and causing all sorts of electrical faults.
If it is faulty all the batteries and alternators you throw at the car will not cure the situation. It is the first thing to check!!

bob gauff

 

Is there a specific procedure to test the Terminal Post, or just visually see if it looks melted? I believe that is where we tested the alternator voltage earlier today and got progressively lower readings starting at about 8 volts while the car was running (after being jump started).

Thanks.

 

Alternator replaced, all voltages read correct, error messages gone, car starts and runs fine.

Took a little effort to get the alternator seated just right and we had to finesse the belt onto the alternator pulley with the handle of a hammer, but all turned out well.

Also shorted out the busted Coolant Sensor with a bit of wire . My coolant levels are fine but I'll keep an eye on it until I can get the sensor replaced.

Thanks to all for their advice and assistance.

 

Good to hear! Come back soon