I went to my 2002 XJ8 today and it wouldn't start.
Turned over but wouldn't fire.
A code check came up with P1638 and P 1642.
P1638 says, CAN LINK CCM/INSTM Network malfunction.
P1642 says Fuel Pump monitor circuit High Input.
Can someone please translate?
Thanks
Bill W

 

Any one any ideas? I have a non-starting car with the DTC's in the above thread
Thanks


Bill W

 

Clear them. Which come(s) back first?

You may need a new pump.

 

Check for fuel pressure.If you have no fuel pressure check for power at the connector to the top of the fuel tank. If you have power at the connector to the roll over valve on the top of the fuel tank, but the pump does not run, you need a pump. More than likely you will need the harness that runs between the roll over valve and down to the pump, they are a common failure.

On a side note, that ECM CAN circuit to instrument cluster code - I saw it on an X-type once, causing a security system malfunction, which caused a no start. The key transponder in the column wasn't getting power from the instrument cluster, had to put in a used one. This code also frequently sets when your battery voltage goes low.

 

I've been checking the car today and it would seem that the problem is that there is no signal (12v ?) from the Engine Management ECM to the trunk located pump relay. I have the battery on charge at the moment, but will try and make more progress on Monday, tied up tomorrow. Bill W

 

It seems that the White/Red wire, that comes from the ECU and goes to the fuel pump relay coil, extends an earth that operates the relay, firing up the fuel pump. I disconnected the 54 way multiplug in the trunk and put an Earth in the White/Red wire and the pump fired up. Today I have to get to the ECU in the engine compartment and disconnect the ECU and put an earth on the White/Red wire that feeds to the pump relay and hope the pump fires up ???.


Bill W.

 

Today I have been having a good dig into the Fuel system, and I think I can rule out the non-starting being a fuel problem. As I am working on my own, I can't tell if the fuel pump is activating when II may have flooded the engine with my earlier attempts to start the car crank the engine. I replicated the earth from the ECU and had the fuel pump running all the time. I then tried to start the engine, but once again nothing. The battery was fully charged. After the cranking, I pressed the valve on the fuel rail and fuel came out at pressure. Tomorrow I shall attack the spark side of the problem. All plugs out for a spark check ( They are new Iridium plugs ). After the cranking and the non-starting, I plugged in my code reader. All that was logged was a P1000. Mystified!!! Any ideas anyone????????? Bill W.

 

If you flooded it you may have bore wash. Use the search to get suggested solutions.

 

Spray starting fluid in the intake. If you have bore wash this should kick it off enough to get it started.

At any rate you should have the engine attempting to fire with starting fluid.
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After taking the plugs out this morning I found them all wet. Spun the engine to blow any vapour out, cleaned up a plug, connected its coil, earthed it, and it sparked OK.

I will clean up all the plugs and put them back and see if it will fire, after putting a squirt oil in each cylinder and spinning it over with the fuel fuse out. Fingers crossed.

Has anyone got a DIY method of checking fuel pressure? Or can recommend a gauge to do the job?

Thanks

Bill W

 

If it is bore wash there are posts about what to do in the S-Type forum (only the S 4.0 suffers).

 

Hold the gas pedal all the way to the floor, crank it, stop, crank it again, stop, crank it again: as soon as you sense it is trying to start, let up the gas pedal and crank it. I think you are flooded. Barring that: try starting using starting fluid, as suggested above.

Bore wash (oil washed off the sides of the cylinder so you have no compression) is really rare in an 02 engine.

Final question: what secondary tensioners do you have? If not metal, you may have slipped a sprocket and are out of time.