307
months ago.” Since grounds are a common cause of trouble in the Jaguar XJ-S, just go ahead and add a ground strap as
suggested on page 553.
FF67 -- SECONDARY AIR INJECTION SYSTEM: Charles Randle says, “My '94 6.0 started having FF67 set a
couple of months ago. I read up on it in the ROM, which tells me just enough to understand a dozen things that may
cause the problem. However, there is one ambiguous sentence that is a large gray area, so I took it to my local dealer
after talking to the Lead Technician on the phone. The simple things I could check myself I did. I determined the Air
was coming on and apparently in the right (as printed) sequences. The tech spent an hour verifying this on the JDS, and
called Mahwah. Two days later they faxed a "Decision Chart" and a possible problem/solution. It seems the PMCF on
all the 6.0's might have come from the factory with the PROM set too sensitive. During any of the secondary air
functions the PROM is looking for a certain voltage from both O2 Sensors. If it doesn't see a signal of this magnitude,
it sets FF67. And that is all it does. It doesn't go open loop or any other deregulating function. The bottom line is, the
dealer gave me the "Decision Chart" and said I really didn't want to pay him $78.00 an hour to verify 3 pages of
decision charts. He also gave me a mail for service procedure to send the PMCF to Delphi Diesel Systems for testing
and installation of a less sensitive PROM. To date I haven't either completed the Chart or contacted Delphi. The
JAGUAR NA procedure when the cars were under warranty was to have the dealer ship the PMCF to Mahwah, who
then sent it to Delphi and it was returned to the dealer COD for work/parts/shipping. For the time being, I am resigned
to ignoring the FF67 and dumping the code each time I won't be using the car for a while. There is no way to disable
the PMCF signal without disabling future serious codes that you might want to be notified of.”
Michael Hahne concurs: “My '94 XJ12 has the same FF67 deal. I replaced the O
2
sensors and had the recall done, and
it still shows up once in awhile. I talked with several knowledgeable folks who said it's probably clogged Air Injection
rails. It's a nasty job to clean these out, but hardly necessary for the kind of driving we do. It's mostly an emissions
thing. I've driven mine that way, occasionally clearing the FF67 code, for 10's of thousands of miles. No troubles. I
drive my '94 XJ12 from Chicago to New Orleans almost monthly. My car now has ~90,000 miles. I drive it daily to
and from work, a round trip of ~160 miles. Just drive the beast, and don't worry.”
FF69 -- DRIVE/NEUTRAL SWITCH: Alan Baker says, “This is a common fault on the XJ40's of that era, (they use
the same ECU). I'm told that the 'erroneous' Code 69 is caused by the battery voltage dropping too much during
cranking. It may be worth checking the battery terminals and connections for corrosion or possibly changing the battery
if it is of some age.”
Gregory Wells adds, “I was always told the FF69 involved the way the key is turned to start the car. If you grab the
key and turn it to the start position in one motion, the FF69 can be set. If you grab the key, turn it to the run position
and pause for just a brief moment before continuing on to the start position, the code won't set. I was told that the ECU
circuitry would not "see" the voltage level it was looking for if you passed through the run position quickly, rather than
pausing briefly, and this is what triggers the FF69 code.
“This isn't supposition, as we have many, many reports from customers that this procedure does keep the FF69 from
being set. The nice thing is that it costs nothing to try it.”
CLEARING FAULT CODES -- 6-CYL: Gary Penovich says, “On a ‘94, you can clear the fault code from the ECU
without disconnecting the battery. It's a piece of cake. Open the dash trim panel that's underneath the passenger airbag
by pulling down on it. Unscrew the passenger heater vent cover. Remove the small trim panel from around the heater
vent. You should see a purple connector attached to a yellow(?) wire. The connector has only one conductor in it, and
it isn't connected to anything. Short that conductor to ground for 3 seconds. It will clear the fault code. The process
may be the same for all AJ6 powered XJS, perhaps AJ16 as well.
“I have actually moved the connector outside of the trim by running the wire through the vent cover. Now, I can access
it simply by swinging the dash panel downward. It comes in handy after disconnecting sensors while the engine is
running. The ECU will flag a fault even if the key is on with the engine off!”