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Becm and Engine ECU losing security sync


martinc

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So after resolving my EKA input problem, my car is now unlocked and security is operating properly from the remote, but the car just won't start.

Turning over no problem, but not a hint of trying to actually run.

Browsing through the topics there seems to be an issue sometimes when after a dead battery scenario the engine ECU loses security sync with the Becm, and on the Bosch Motronic versions (as opposed to GEMS), a few posts have stated that if they have lost sync, when the ignition goes to position II, the engine warning lamp will not illuminate. Mine however is illuminating ok.

Does anyone know if this definitely indicates the engine ECU is fine (in terms of security sync) before I set about fuel system troubleshooting?

Martin

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With Gems the check engine lamp confirms security synch twixt BECM and itself,but with Motronic from memory it does not.It must be a year ago that I had a 4.6 Bosch LP with exactly the same problem.I could redo the security learn with Testbook then a week later it would lose it.The owner was very vague and did not offer much help with exact symptoms,but the car had a flat battery each time I went to it.I fitted the uprated alarm receiver and a new engine compartment fusebox and sent it back.(Could not find any loom faults/switching issues)Not heard from it since,and it came via a garage who would have not have an issue in complaining.A good battery,(Diesel spec one.) new alarm receiver,dry non rotten wiring and an unburnt fusebox are a big help for a reliable P38 RR !

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Thanks for the update, I've had the AA out to it who after checking the plugs because it "sounded like it was flooded!", then hooked up the diags and found fault codes P1667 & P1672 on the ECU. From browsing the forums again it would appear this definitely means the loss of security sync between Becm and ECU is the issue. However, the garage it's being recovered to is a general mechanic who has done all the other work on the car for me, and does not have a test book or rovacom. He says he can get his hands on one, but has spoken to someone else who has said the keys , Becm and ECU all need to be programmed with new codes!

Can anyone who has testbook confirm this? From the posts I've read I don't think this is correct as I got the impression you could set the ecu into "security learn" mode and it re-syncs with the Becm.

Can anyone who has testbook / rovacom confirm what the proper procedure is for correcting this problem.

Thanks

Martin

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