Thread: M and S lights, turns over but no start

Originally Posted by shack

What CAN fault is showing?

P1843 CAN timeout monitoring, and P1842, CAN level monitoring..

And now it won't start again.

CAN level monitoring.

Highly unlikely to be true, you would need the wrong TCU fitted.

It's most likely a phantom fault from another issue, such as low voltage while cranking, a failed TCU or engine ECU or wiring problem.

Timeout monitoring is usually because of low battery voltage or the ignition powered on with the engine ECU plugged in.

Or.... if your have a NNN ECU, flashing the ECU with a new firmware.

Cheers

Thanks, James. No, it's MSB. Wiring is possibly the issue, it's been a bit problematic. I did have a low voltage event, but it appears to be ok, and the fault returns without actually cranking, but I guess the combination of a few things, and the code being set even though the nano clears it, could all be contributing. Going out to check battery level even though it cranks fine. I know they are sensitive to voltage.

One thing I do not have a spare of is the ECU. Question as a follow up. When the nano says it has learned the security code, Does it store it on the device? It said that even without an SD card present.

It's not the nano that has saved the security code, it's probably badly worded.

From memory it's saved in the serial EEPROM in the engine ECU.

You can clear the fault with the engine running from memory, see if it comes back while still running.

It's quite possible the TCU is failing.

If you have another from ANY automatic D2, you can simply swap them to check.

MM says the batt is at 12.3v, nano says it's 12.0. ?Got it on charge in any case. I am getting an occasional position switch monitoring fault, but no sign of that in the odo or selector quadrant. The security horn, which I had never heard until Sunday, sounds when I put the car in N, running or not.

Apologies to the OP, but I don't think I'm hijacking his thread, we are facing similar issues and we could both learn.

I wonder if this could be causing me any issues?