megan11 1.4 petrol no instruments or pas

[autoden]

Got this in today to give me headache. Car starts and runs ok. There is nothing on instruments ie no speedo ,no rev counter, no temp or fuel. It has good earth and 12v supply. No comms with PAS, instruments, injection or restraints. Can bus faults to the four modules listed. Can low is 1.7v, can high is 1.7v so something is pulling can high down to 1.7v. With clip it shows no faults in other modules only, restraints module locked! car does not appear to be accident damaged. Is it possible for the airbag/restraint module to do this? Looking to send this to have data cleaned in module and unlocked. Am I on the right track here? Your thoughts here gentlemen.

[Dunker]

Had a very similar fault the other week and it was the cluster that had died. Strip yours down and have a look for a burned up surface mount transistor. Mine was proper black and burned up. Not saying its same as yours but worth a look. Although looking at what you have not communicating it could be rusty connections on one of the multi-plugs on the BSI. Never had an airbag module cause that much trouble on a Megane even with crash data - never say never though - tis frensh.

[autoden]

Swapped the clocks' no change. Have checked all multi plugs on bsi. Don't like french, but I cannot complain, after all they paid my mortgage off early. See what happens when its been cleared. Need to get CAN high up to spec.

[clusters]

Silly question, unplugged the restraints module and try it?

[autoden]

That would be my next job if clearing data don't help. Its just that its such a pain to get to.

[Dunker]

Also, when you scope the CAN lines on Renaults (and especially Meganes) the waveforms sometimes don't look right. What I mean is, CAN low can look exactly as you would expect and CAN high can sometimes look distorted with regard to intermittent vertical peaks looking odd. Not exactly a mirror image of its opposite. Hard to explain unless you have seen it but it is normal and doesn't seem to affect comms.

[clusters]

That would be my next job if clearing data don't help. Its just that its such a pain to get to.

Should have been the first thing you did to check for shorted module or corroded connector. If the wiring runs under the carpet and along the kick panel, that's another place to look for corroded or pinched wires. Nobody said it would be easy. Carpets wet at all?

Should add that I had a similar experience with a different car, corroded connector on the restraint module under the seat. So much green you couldn't see the connector. Car still ran but no comm to any module and a dead cluster.

[autoden]

Dunker' thanks for that, I thought I was going mad when I scoped the high and low. It did look like a mirror image,almost. And yes to cluster, I know I should have checked under the carpet etc but it was a long day and I got bored with it. Ah well back to the drawing board. Thanks for staying with me guys.

[autoden]

*FIXED* Load tested the wires from fuse box next to glove box to key reader. Found one that failed. Traced it up to heater box area and found green dot on wire. All good now but what a pig to find.

[Meat-Head]

Sorry only just seen this.

had one same, but pas worked, was plug on pas 5 wires one bad .

what did you load it with and where EXCATLY it bust?

[autoden]

Meaty, cant recall how many wires on pas. To load test I normally use load pro leads, but on this one I used a 20w bulb from battery because of clearance.

[Meat-Head]

The one we had in at www.meat-head-motors.co.uk 2 thick power/gnd then ignion sense, 2 can in 2 can out