Immobiliser issue B2798

[cptspaulding]

Odd one.

Had a 2zz swap done 18 months back & only recently discovered how the swapper fudged the immobiliser. He simply took the transponder reader ring from around the ignition barrel, taped the old Celica key inside it & concealed the lot beneath the steering wheel casing. Which has been working fine until now - albeit I effectively have no immobiliser.

My issue is intermittent starting issue in hot weather, whether the engine is hot or cold. It turns over fine (sounds a bit faster than my normal turn-over, may be my imagination) but refuses to start. I can leave it, go back in 10-15 minutes & likely it will start again. Never gone longer than 30 minutes without starting. Happened one day a month back, been fine since but did it gain a few times yesterday.

A month back I got the local garage to come around to the work car park with their computer & it picked up the code B2798 - Immobiliser communication malfunction no.2.

Firstly has anyone had the same experience with immobiliser issues in hot weather?

Lacking any takers on that, my plan is to do the following.

1. Get a new blank key & have it cut appropriately.
2. Transfer the guts of the Celica key to the new blank key.
3. Relocate the transponder reader ring back to it's correct location around the ignition barrel.

If that all goes well (in cool weather) I'll then carry on to.

4. Do the immobiliser pedal dance to get my original key working with the immobiliser.
5. Do the pedal/door dance to get the locking plip buttons working on the new key.

This should get the immobiliser to function again as it ought to but likely as not, it won't address the hot weather starting issue. So what then?

Could I have an issue with the immobiliser reading ring? Worth replacing that with another?

While waiting for that is there another way to bypass the immobiliser in the wiring, shorting a couple of the pins on the ECU? It's a UK Celica 2zz ECU.

Any/all thoughts & advice appreciated.

[Call the midlife!]

Not familiar with the 2zz immobiliser functionality etc but doesn't the standard one disable starter and fuel pump?
So if the starter is turning it might suggest hot weather fuelling issues?
My tdci can be a real bitch to start when the engine is hot, some mechanics have suggested it's a lazy fuel pump, starts first time every time when cold.


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[cptspaulding]

Not familiar with the 2zz immobiliser functionality etc but doesn't the standard one disable starter and fuel pump?
So if the starter is turning it might suggest hot weather fuelling issues?
My tdci can be a real bitch to start when the engine is hot, some mechanics have suggested it's a lazy fuel pump, starts first time every time when cold.


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Ah, may be getting closer...

A few months back it didn't start, with very similar symptoms. Wouldn't bump start either, so I suspected fuel issues. Checked my fuses & the 7.5A on the fuel pump was blown. Replaced it & it started again. BUT, being an electrical engineer I understand that if a fuse blows then there is generally a fault on the circuit that makes the fuse blow.

Can anyone confirm that the starter motor is disabled by the immobiliser?

[shnazzle]

Nope just fuel

[cptspaulding]

Nope just fuel

Thanks for the confirmation. Back to the original post.

If it was fuel pump surely it would show up whilst driving, not just on starting? Possibly a lazy relay to the fuel pump?

[shnazzle]

Nope just fuel

Thanks for the confirmation. Back to the original post.

If it was fuel pump surely it would show up whilst driving, not just on starting? Possibly a lazy relay to the fuel pump?

Might not be priming but that doesn't explain the odd code

[Call the midlife!]

Nope just fuel

Thanks for the confirmation. Back to the original post.

If it was fuel pump surely it would show up whilst driving, not just on starting? Possibly a lazy relay to the fuel pump?

Might not be priming but that doesn't explain the odd code

Looking back it was the useless Clifford alarm that was fitted to mine that isolated the starter and fuel pump, apologies for the misinformation.


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