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Richard, Jaguar Technician
Category: Jaguar
Satisfied Customers: 15492
Experience:  12 years at a Ford/Lincoln Mercury and Jaguar dealer as technician and shop foreman.
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I have a 1998 jaguar xj8 cranks but wont start have engine

Customer Question

I have a 1998 jaguar xj8 cranks but wont start have engine fail safe coming up on the dash , have no spark
Submitted: 1 year ago.
Category: Jaguar
Expert:  Richard replied 1 year ago.

We may have a problem with the transmission rotory switch on the transmission as this signals the ECM that the transmission is in park or neutral and the ECM will then energize the injectors and coils. See if the engine will start in neutral. We then should use an OBD II scan tool to read fault codes. Let me know.

Customer: replied 1 year ago.
will not start in neutral codes I get slm,codes u1135,p0100,p20e2. bpm codes,u1041,b1794 ,u2012,b2368,b1595,b1446,b1875,b1352,b2335 . I have changed crank sensor and when I did I unhooked battery , I have no engine codes
Expert:  Richard replied 1 year ago.

Sorry for the delay. If we are sure we have no spark please check for injector pulse when cranking. Then make sure we have power to the coils on the pink/white wires as the coils should have battery voltage with the ignition ON.

Customer: replied 1 year ago.
no power to the coils not sure about injector pulse but the plugs are dry
I have fuel pressure
Expert:  Richard replied 1 year ago.

Ok no power to the coils is definitely a problem. If we do not have power to the pink/white wires with the ignition ON then we need to check the ignition coil relay and the fuses. The fuses you need to check for power on are fuse #14 and #18 both 10 amp in the small engine management fuse box in the engine compartment and the relay is located under the ECM enclosure in the passenger rear of the engine compartment. Click on the link. Visually inspect the fuses then make sure voltage is present to both sides of the fuse with the ignition ON.

Customer: replied 1 year ago.
checked fuses all have power swapped relays around with ones that I now are working still no start . I unhooked battery over night no codes but when I started to crank car the failsafe engine popped back up as soon as I started to crank car
Expert:  Richard replied 1 year ago.

The pink/white wire at the coils definitely shows no voltage with the ignition on.?

Customer: replied 1 year ago.
neither wires light test light when ignition is on or when cranking
Customer: replied 1 year ago.
how can I check and see if there is power to relays?
which wires or terminals should be hot and when?
Expert:  Richard replied 1 year ago.

Go to the ignition coil relay. The relays may not be in the correct order so we will need to go by the wiring color. With the ignition on we should have power on the white/pink, brown/white and the pink/white.

Customer: replied 1 year ago.
seem to have power to relays when I turn key on I have power to three wires the wire colors are different than what you gave me so I checked them all, all the relays have power to three wires could it be the security system ? my daughter was driving car ,went in the store opened trunk and set alarm off unlocked door to turn alarm off would not start after that.
Expert:  Richard replied 1 year ago.

Could be. Disconnect the negative battery terminal cable for about an hour. Put a charger on the battery just in case it is a voltage issue. Reconnect the battery and lock/unlock the driver door using the key in the lock cylinder. Also please confirm with a digital multimeter that power on the ignition coil connector.

Customer: replied 1 year ago.
well I unhooked battery while it was un hooked I cleaned the throttle body and re-hooked battery locked and unlocked door the car coughed I cranked it with the pedal on the floor several times and it started. I let it run for a couple min. shut it off started right back up . I turned it off and put it back together now it wont start I have unhooked battery reset everything still wont start
Expert:  Richard replied 1 year ago.

Try holding your foot to the floor again and we should also again try spraying some cleaner into the air intake while an assistant cranks the engine.

Customer: replied 1 year ago.
tried that no luck not getting spark again not sure i am getting fuel either that is why I sprayed it but didn't even cough what could cause no spark and or fuel ? relays are fine fuses fine ,reset by unhooking battery no faults show up on dash until I crank then failsafe engine comes on
Expert:  Richard replied 1 year ago.

I think the problem may be either the security or possibly the transmission rotory switch as that will cause no ignition and injector pulse. We do need to make sure power is present at the coils. Try moving the shifter back and forth to see if it will start.

Customer: replied 1 year ago.
did that and no go
Customer: replied 1 year ago.
if it the security could it be the key or ignition switch? sorry I didn't get back top you I work second shift
Expert:  Richard replied 1 year ago.

It would actually be the mobilization of the ECM which would need to be reset with the Jag factory tool. We should start from scratch. Double check for spark, fuel pressure and injector pulse ti see what is missing. Also with a compatible OBD II tool read all the faults codes if any and clear them.

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