Hello all,.

1999 Volvo C70 2.3 T5 Cabrio.

This is the range of cars that had a seperate Immo module, and no CEM.
The car has come in for a new electric window motor and auto trans valve block.
It's had this intermittent non-start issue throughout.

I've got an intermittent crank, no start issue - Codes 720A and 2400.

Code 720A is apparently telling me that the Engine doesn't get the matching code from the Immobiliser.
Code 2400 is apparently a Fuel relay feedback code

As these cars are known to have intermittent fuel pump relay module issues, we took the relay module apart, and operated the relay contact by hand, and it seemed to work, the engine started, the fuel pressure is fine, all seemed well in our diagnostic universe.
So we ordered a new relay, it arrived today, fitted, car started and ran fine.
Turned off to remove fuel pressure test set and refit fusebox covers, now no start.

The Immo is reporting that it sees the transponder, and is giving the code to the Engine ECU, and has no codes.
If I operate the ignition switch without the key present - I get a "no transponder" code from the Immobiliser.
So it's not the antenna ring, or the transponder.

Wiring is all sound, no other fault codes present on the car at all...

Fuel pump relay works fine, engine cranks quickly, but no start...

Has anyone successfully managed to bypass the Immobiliser on the M7 ecu?
Or any ideas on how to go forward?

TIA,

Mike.