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1) I can't figure out what it takes to cause the car to cut-off (hard acceleration, coasting, deceleration, etc)
2) I only have two known electrical problems with my car
1) When I turn on my tail lights (and headlights) the bulb out indicator come on even though all the bulbs are working
2) When I use my key fob or key to open (and lock?) the doors only the right headlight flashes. The headlight both work with the headlight switch
I gave my daughter my 96 XJ6. This 95 xj6 is new to me.
3) I swapped the ecu and ecu relay from these two cars. Her car works fine, my car cuts off.
4) I swapped the cks between the cars and same problem.
5) I swapped the ignition coils with no change.
6) I swapped the negative battery terminals with no change.
7) I checked the battery cables right after the car cut off and both cables were cool to the touch.
8) I cleaned the battery posts and cables.
9) I made sure that the battery is fully charged!
10) Radio stays on when the car cuts off. Radio is aftermarket but gets its power from the radio harness.
Today I plan on checking ground wires.
Might the problem be he body processing module?
I plan on trying to get the car to cut-off while wiggling relays
Any other ideas?
My car has 120,000 miles on it and drive as nice as can be except when it cuts-off!
You’re gonna need to provide more detail. Is it always exactly 5 minutes? Does the idle wander? Does it just shot off, or does it sputter? Does the engine have to be hot for this to happen, can it happen cold? How many times/how long have you known that this can happen?
1st, I did replace the TPS and the car still cuts off while driving.
I do not think that it is exactly 5 minutes before the car shuts down but it is close to that. It certainly is not after 1 minute. I just notice that this happens this evening. I had the car out for a nice drive (1 hour) came home did a few things and about 30 minutes later I started up the car and it stalled. I restarted the car and it turned off after about 5 minutes. This happened 5 times. After a few minutes the idle started fluctuating and the car just turned off with no sputtering. I would say that it isn't a fuel problem.
I do have an OBD2 reader. The CEL has been off for the last 300 miles after I charged my battery.
Very odd that you’re not even getting the check engine codes for engine stall or transmission fault (because the engine stalled). That is very odd.
Next time you’re able to, run the engine and wiggle the MAF connector. Those occasionally work themselves loose. They make poor contact and then the ECU doesn’t see it and poof!
The XJS also has a master relay in the knee bolster. I wonder if the X300 has that as well. It’s called a “Multi Function Unit”. This may be the root of your problem. See if the x300 has one of these. If it does, swap it out.
When you say you "swapped the cks" with your daughters car, do you mean the crankshaft position sensor? If not, I would definitely try swapping it, as it is prime suspect for most strange X300 faults.
The ECU is powered by 2 relays and both relays are needed at all times
The small right engine bay fuse box relay # 9 ( called the ignition positive relay ) can be swapped with the same on the left engine bay fuse box ( this left relay in reality only controls the horn )
The large ECU controlled relay# 5 which is controlled by the ECU and brings power back into the ECU , you can swap this relay with one of the same part # like a headlight , fog light , or A/C clutch
The fuel pump is controlled by a fuse in the right heelboard fuse box in front of the rear seat and is also called a ignition positive relay
You can swap this relay with the same left engine bay relay
There was a odd cases where the pins where bent in the OBD 2 connector shorting out and popping the fuse which is shared with the fuel pump control at point 7
Don't remove the troublesome large connector above the fuel tank ( BT4 ) yet but you can wiggle it before removing it
Last edited by Parker 7; Sep 23, 2021 at 12:13 PM.
When you say you "swapped the cks" with your daughters car, do you mean the crankshaft position sensor? If not, I would definitely try swapping it, as it is prime suspect for most strange X300 faults.
The Crankshaft position sensor can fail partially without flagging a code
One of the partial uses is for fuel pump relay enable
You can remove the fuel pump relay and jumper the sockets with a heavy jumper wire and this will directly power the fuel pump eliminating the relays control by the CKPSThis will keep the pump running with the keys in your hand so plan accordingly
Recommend using blade type connectors in the sockets for best pump electrical current flow
The auto parts stores will sometimes have some spare heavy gauge wire in the tool box behind the counter
Car cuts off and then restarts a second later
