Lotus Elise Exige T4 and T4e ECU

The Lotus ECU for the toyota powered Elise and Exige comes in various flavours.

The (early) T4 ECU series

Part A120E0005F is used in the very first production of the Toyota powered 111r for the EU market. It is a wedged shaped box with no cooling fins, only present in cable throttle cars. They are called T4 ecu’s. The later fly by wire throttle ecu’s are T4e series. More about later.

Its successor B120E0005F is also fitted to cable trottled cars only. Hear-say suggests that this version of the ECU can be flashed with a different fuel map whenever the cams, inlet induction or supercharger is added. An option which isn’t possible with the A-series.

Cam switch point lowering can be equally done on both, provided the workshop has the right tools.

I would like to quote these guys from eliseracing about the topic of reduced cam switch point without altering the fuel map or variable timing.

source: https://www.eliseracing.com/aspirated-ecu-and-tuning-packages

It is important to note that reflashed ecu conversions for these vehicles seem to perform very badly even compared with the standard factory map. There is a big belief that switching the cams over earlier increases power, (ie VVL effect switchover point). This could not be further from the truth on aspirated 2ZZ engines. When the VVL is engaged at 5700 rpm the effect is absolutely awful with a huge drop in power between 5700 and 6200 rpm. ./. We asked our pro driver to lap as quickly as possible for five laps with 5700 rpm switchover, his laptimes where all within 3/10's of a second of each other. We then swiched over to 6200 rpm switchover and immediately the car was 8/10's of a second quicker per lap again with 5 laps completed. ./.

How to remove the harness connector from the A- and B120E0005F ECU? Slide the top end of the connector out. At some point it will start to eject the connector.

You may find part numbers A120E0005F  and B120E0005F in 2004/2006 elises 111r. There are some derivatives of the T4 ecu:

  • ALS3M0014J – T4 ECU – manual exige cup supercharged 240, 04-05MY
  • A121E001F – T4 federal USA replaced by C121E0001F
  • C121E0001F – T4 federal USA 04-05 MY
  • ALS3M0249J – reported on 05 federal car – (Lotus Sport) T4 federal USA 05 – not in database

The T4e ECU series

The later builds (electronic throttle, airbag, small reflectors in the top corner of the headlight lenses) is fitted with a smaller ribbed ECU, called T4e. These go by the product ID:

  • B120E6501F – T4e electronic control module ECM uncalibrated – dealer programmed 1ZZ, 2ZZ, elise, exige ’08 MY onwards
  • A120E0029F – T4e – replaced by B120E0029F
  • B120E0029F – T4e ECU unprogrammed
  • C120E0029F -T4e MY 06-07 EURO
  • B121E0009F – T4e – federal, usa/canada 06-07 MY
  • A128E6009F -T4e exige S – 06-07 MY
  • A129E6003F – T4e exige S- 06-07 MY – USA
  • ALS3M0244F (Lotus sport) – T4E ECU with track programme
  • BLS3M0016K T4e cup 240 06 MY