Hi Dave,

Looks like I can't get the Modis till the weekend :-(

So in the meantime, any trouble shooting suggestions? I did a pretty through inspection of wiring harnesses around PCM, only found some very minor damage to wire isulation. Always possible something could have been over looked.

Do you think with what is functioning that the HS CAN is functioning?

When we did the initial scan, seem like everything but the PCM would communicate. We didn't test all of the sub systems, didnt know where to start and be productive.

As always thanks!

 

Pic of damage.

Have all parts, just need to get her running.

 

If you have a multimeter, you can check voltage on you CAN buses, and ohm them out with the batt disconnected, from the DLC.

HS is pins 6 and 14, should be 2.3 and 2.7v to ground on those pins with key on, and with batt disconnected, ~62 ohms from one to the other.

 

Hi Dave,

When referenced to ground, pin 6 had 0V and pin 14 also had 0V.
The resistance between pin 6 and 14 was 3.8 ohms.

Obviously not good. Something is definitely pulling down the CAN buses.
Not sure where to go next.

Thanks,

Nick

 

You had 0v with the key on, but you were able to communicate with anything?

I might have made my post confusing with punctuation, but voltage should be checked with the key on, and powered up. Resistance checked with the battery disconnected.

 

Yes sir, voltages checked with ignition on (key at position II), meter set to DC.

Resistance measured with ground disconnected from battery.

pin 3 (MS CAN) read 2.6VDC
pin 11 (MS CAN) read 2.25VDC

pin 4 = 0V
pin 5 = 0V
pin 8 = 10.0V
pin 9 = 11.4V
pin 16 = 12.6V

 

Next step would be resistance to ground, again, no battery, on HS CAN, see if you're shorted. Past that it is tracing wires, or disconnecting modules. When disconnecting modules you need to pay attention to what is branched off, and what is pass-through. If there are 2 HS CAN wires to a module it is branch(aside from IP and ABS, which are terminating) 4 wires would be a pass through, and cannot just be disconnected, as the CAN goes in, and out to the next module.

Pass through modules are:

PCM
EAS
Parking brake(known for corrosion)
Rear diff module
T-case module(again, corrosion)

The SRS module also can not be disconnected and allow a start, but it can be disconnected and voltage checked to see if it comes back up.

What you're seeing on MS CAN is what you should also be seeing on HS.

 

Only had a minute to look at vehicle last night.

Both pins 6 and 14 were reading 3ohms with respect to ground.
Grr, close enough to being shorted.

Been searching my RAVE manual, cant find a diagram giving location of the 10 modules that run off th HS CAN or the specific CAN wire color, other that twisted pair.

From what I have described, which modules would you start with first?

Tracing wires is fine, which module wires would you start with first?

Thanks!!!!

 

The LR3 wiring diagrams seem to show mostly YB and YN wires (yellow with black, yellow with brown); that is the tiny letters at the junctions. In the Module Communications Network section.

As for connector locations, I'd like some help with that as well. In the the D2 RAVE the electrical library has the connector list and photos. Where is this in the LR3 manual set?

 

Hi Dave,

Was able to get hazards to stop flashing by disconnecting connector: Trans auto YMD505900A (see attached pic)

With YMD disconnected, resistance across pin 6 to pin 14 on DLC is now 95.6 ohms.
With battery reconnected and YMD still disconnected, with DMM referenced to ground, pin 6 had 2.54V and pin 14 had 2.3V on DLC.

Next step, I reconnected YMD and DISCONNECTED C0635 from ECM. Looks like the wire bundle went from YMD to C0635.
With C0635 disconnected from ECM, resistance across pin 6 to pin 14 on DLC is now 91.5 ohms.
With battery reconnected and C0635 still disconnected, with DMM referenced to ground, pin 6 had 2.5V and pin 14 had 2.36V on DLC.

What do you think???