Afternoon Guys

A strange fault has appeared on my 2004 XJ8, both rear struts have dropped to their knees and the fault code is U1262, SCP communication error between the REM and the ASM and another code form the instrument cluster, no data from the ASM, this happened all of sudden last Saturday, no problems on Friday though, SDD v160 can’t connect to the ASM either and won’t let me clear the fault codes, as I says it needs to update for all functions to work, so i can’t run the suspension calibration program, I’ve replaced the battery (less than year old), done a hard reset by holding the +/- cables together, but still the same, SDD/IDS v130 just hangs when i i try to read the codes. Any ideas or help greatly appreciated.

 

https://www.troublecodes.net/ucodes/u1262/

 

Strangely, the U1262 has cleared, but now I’m left with P1672 & U2454 and still unable to connect to the ASM.

 

The U1262 has strangely cleared now, but I’m now left with a P1672 CAN ECM / ASM Communication network fault on the ECM and U2454 CAN ASM Data Missing on the IC (instrument cluster), I’ve checked the C+ & C- cables at the ASM & IC and get 63 ohms, which is the correct value for the CAN Network at both of them, I didn’t have time to check the voltages or for a short/open circuit as it was getting dark, just need to check the CAN pins at the ECM (didn’t have the 5 point security torx bots, arriving tomorrow), as the Ω readings from the IC to the ECM were 0.0 ohms, which suggests a short/open circuit, but I would’ve thought a short/open circuit from the ECM would‘ve affected other modules as well?

 

Where/what pins were you testing to get 0 Ohms? In some cases that is the correct value. Check ASM connector for corrosion. However your ASM is last on line on the can bus and supplies the second half of the 60 ohm value. If its bus lines were bad you would not see the 60 ohms it would be 120.

 

If you have access to an oscilloscope that would be the easiest way to confirm CAN data signals are reaching the pins on the ASM. If both of those CAN wires have normal looking signal, check power and grounds of the ASM (use a test light that can actually carry some current, not just a DMM). If you have power, ground, and data signal, then sounds like the ASM has died. Assuming the pins are not corroded (which seems unlikely due to the location of the ASM behind the rear seat).