I have a 2005 X-type and it suddenly went into limp mode. I lost the speedometer, the tachometer, and almost every warning light lit up. It was a dry evening and had been dry for a week or more. When I checked the codes there were a dozen or so and most were CAN related majority for engine and transmission. I reset the codes and got about 7 miles before reoccurring. Both the battery and alternator have checked out fine. Research has turned up two common issues of the wire harness of the gauge cluster. Han anyone else had this issue and successfully remedied it. What can I do to start diagnosing or at least eliminating causes.

 

CAN communications are usually carried on twisted pairs of yellow and green wires between the various CAN connected modules.
I think you should normally measure about 200 ohms of resistance on the CAN line depending on which module as some are simply passing CAN through to the next in the chain while others act as a CAN hub or terminator.
There are some prior threads from other members that have methodically traced CAN wiring and taken measurements. You might want to do an advanced search to see if you can locate and read them to see if they might help guide you.

However, the best place to start is by downloading the schematic for your 2005 model, but be aware that 2005 saw a change in production so there are two schematics (up to 2005.25 and after 2005.25).
In the later pages (somewhere around Fig 20) is the CAN Bus layout showing you how the modules interconnect, connector and pin info.

Rodent activity under the hood is unfortunately common due to the use of vegetable based wire insulation throughout the looms.
Modules to pay particular attention to a re the ABS module, TCM and instrument cluster.

TCM is known to suffer some water ingress following the loom down from the heater assembly. Water overflows the cabin filter intake if the scupper drains are blocked and that can lead to a damp carpet in the foot well and water tracking along the cable loom to the TCM.

If you suspect the TCM might have copped some water, you can remove it, open it up and check if the internal side of the main connector or PCB shows any sign of some corrosion which can cause some electrical current leakage.
That corrosion residue can be cleaned back with a small stiff brush (tooth brush) and/or cotton buds using some Meths or Isopropyl alcohol.
If the corrosion has take too much of a hold there might be some connector pin or copper track damage that might need addressed.

Good luck with your hunt.

 

Google canbus diagnostics with multimeter. Read and watch a couple vids. Easy to do basics

 

Jeroli27, can you provide us the codes you got?
h2o2steam, I think the change on the schematics was 2004.25, not 2005?

Start by downloading the workshop manual, link to it can be found on the stickies.
You'll find that the Electrical-section on the manual, has the codes you have, with testing instructions on canbus.
If your codes point to canbus fault, you can pinpoint your issue; ECM, TCM, ABS/TC/DSC, CCM, J-gate or IC, or canbus wiring with multimeter. Number of modules in the network depend on the specs of your car.
As h202steam said, electrical schematics show connector numbers and pinouts as well as network layout.

I recently did extensive research to my 2.5 '04 AWD to find cause for limp mode and P1799 / P1637 codes.
Turned out to be the ABS control module, witch was then rebuilt, and got it on the road again.

On '04MY the canbus should have around 110-120 ohms resistance, measured from the diagnostic (obd) connector pins 6 and 14 if bus termination is ok, meaning that all modules are present in the network.
If you only got 50-70ohms, you have termination missing from the network, if you have more than 10k ohm, you have open circuit, and that's either wiring issue or bad connection etc.
I belive '05MY has the same values: the terminator resistors are in the ABS module, and in the Inst.cluster.
By the way, the TCM is a PITA to get out, its behind the fusebox in the drivers footwell (left hand drive); you'll need to disconnect the whole fusebox to get to it, or even the connector(s).. Theres's two connectors, if you have 32bit TCM, and only one if 16bit. Disconnect the battery first !
Hope this helps, good luck!

 

Mp-x,

You are right....I just have a new puppy introduced at home in the last week, so sleep has been almost non-existent .
Brain is definitely temporarily fried until normal sleep pattern returns in a month or so ​​​​​​.