No Error Codes, No Spark

[Axcontrols]

1998 W210 035

I know a bloke who breaks mercs, sells spares etc. - He has a device for reading error codes out of the control unit.

My Car shows no current codes. It shows one stored code relating to when I disconnected the crank sensor to test it. Cleared that code and now there's no current error codes at all in there.

Car opens, I climb in, insert the key in the ignition, click, steering lock comes off so I can steer (I'm sure the steering wouldn't unlock if there was a key ID problem)

I hear the fuel pump buzz as usual.

Turn the key, engine turns but doesn't start.

I disconnected a plug lead, inserted a spark plug into the plug lead, earthed the body of the plug, cranked the engine, no spark.

So, here's the question, what kind of fault would cause there to be no spark. A fault that doesn't show in the control unit ?

There's 2 coils, tested output of both of them. No spark from either of them.

The fault didn't happen while driving. The car drove fine. Parked it up on Friday night. Came out saturday morning to this problem.

I have two keys/fobs. One of the keys is almost new so not a key battery problem.
I swapped the main car battery out today just in case but no difference so not a car battery problem.

Anyone have any ideas ?

 

[brandwooddixon]

The immobiliser may still be active.

It is possible for the key to open the car and turn over the engine, but unless the correct code is read back it will not start the engine.

If you are sure that the key is not at fault then it could possibly be the key reader in the ignition switch barrel. This is known to fail occasionally, but is very expensive to replace.