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PROM ids

The table below shows the PROM id associated with various Elans and the 13th digit of the Vehicle identification number (VIN) that should help to identify which you have in your Elan.  If the label is still on the case of the ECU you can see the four letter code is printed at the bottom right (at least on the ECUs I have). Level with that on the left is an eight digit code (not the service number, the other one) and the last four digits of that are (in my examples) the four digit PROM id... So, with the ANXZ label I'm sitting looking at now it has the 8 digit code 16129239 and the PROM id read from the MEMCAL is 9239.


Elan type Prom id Code Eight digit label code 13th Vin digit Comments

The most common SE PROM. Can have problems meeting MOT emissions requirements due to the small adjustment range on the CO potentiometer. If your car has one of these and meets emissions requirements without difficulty you should stick with this chip. If your Elan has trouble meeting emissions standards then look at the 9930 below...

N.b.  The 9929 is a fully compatible updated version of the 9239.

SE 9930 ? ? 1

As 9929 but with revised CO potentiometer calibration to ensure that emission standards can always be met within the adjustment range of the potentiometer. See here for details of the retrofit and here for how to find if your car has one. This chip will allow any emissions problems to be remedied but if the car is currently fitted with a 9239 or 9929 then the CO potentiometer will require require adjustment after the chip is fitted to prevent lumpy idle problems.

S2, late SE
US - 49 States
1499 AXMZ 16161499 4

The only PROM used in the S2 and in US 49 states Elans. I've come across one in a Japanese Elan too. Catalyst equipped cars may not hit the Everest targets unless the backpressure from the catalyst equipped exhaust is addressed, although they should still gain appreciably in boost and power.

US Californian 9949 ?




Strict emission PROM for Californian Elans. As above, catalyst equipped cars may not hit the Everest targets unless the backpressure  from the catalyst equipped exhaust is addressed. Does not work in 49 States Elan.

Early version of 49 states?


5849 AWKZ 16155849 ?

A rare closed loop variant.  The comments concerning the performance of catalyst equipped cars given above also apply here.


The VIN can be found in the locations below: