2001 xj with " no bu5" code?

Just dropping in to see if I can get some friendly help in here. From what I've seen thru google there is a bad connection between the gauge cluster and the ECU. Is this right and what should be done to fix this. The engine turns over but will not start and the "no bu5" code somes up in my odometer with the engine light on. Help please.

Try hitting the top of the dash first. It may fit it for a little bit. If not I would pull the cluster, clean the contacts, bend them out slightly and cover them in dielectric grease. Another option is a failed CPS. Not sure a faulty gauge connection would cause it not to start.

The #1 cause of NO BUS and a no start is a shorted crankshaft position sensor. Theoretically, anything on the bus (computer signal highway) could go south and give you problems but it is fairly common to see the crank sensor fail in this way.

Try this. Disconnect the crank sensor either at the sensor itself or at the connector inside of the engine bay near the firewall/#6 injector. Now turn the key to ON. If the NO BUS is gone, that is smoking gun verification that the crank sensor is the culprit.

As mentioned, there are a few things that could cause this but your must rule out the crank sensor FIRST.

Good luck and let us know what you find!

thanks for the info.

Talyn said:

Try hitting the top of the dash first. It may fit it for a little bit.

Click to expand...

That's what I do, about once a week for the last two years.

Replaced the crank sensor and she fired right up. Thanks birchlake. Wish they had put that thing somewhere a little easier to get to lol

Can anyone post up a pic of where to find the CPS? The only plug I can find by the #6 injector is for the O2 sensor for the 4, 5, 6 pre-cat, and the plug for the coil pack on the passenger side of the head.

hot_rod_hooligans said:

Can anyone post up a pic of where to find the CPS? The only plug I can find by the #6 injector is for the O2 sensor for the 4, 5, 6 pre-cat, and the plug for the coil pack on the passenger side of the head.

Click to expand...

http://autorepair.about.com/library/pictures/illustrations/bl011lib.htm

On the transmission bell housing, driver's side, follow the harness up for the connector. Make sure you get the right one for your year, and the OEM crank sensors from the dealer have a good reputation for longevity.

Thanks, if I got it right, the plug was back by the transmission linkage. Pulled the plug and the gages work again, no more "No Bus", but I still get a CEL after cranking, sound right?

Sounds right.