hughandrew

Can I feasible replace celsior ecu with ls400 ecu to get rid of Japanese text everywhere.

also what effect would replacing the factory ecu with an aftermarket like a Haltech do to the rest of the car eg immobiliser, electronic systems. And on that point, I’ve heard people say the factory ecu is ‘locked down’. What does this mean.

CELSI0R

I believe locked down means that you cannot modify the firmware to make the ecu behave differently

LS 400 ecus and Celsior ECUs are not the same because the cars have differences. Highly doubt you can just swap them

Can't say for aftermarket ecus. All depends on how it's installed and what the ecu offers

400fanboy

It won't get rid of the Japanese text.

LS400 ECU's are not modifiable. LS430 ECU's are, and can be modified and tuned like many other cars, because that ECU is cracked. It's hacked. The security\encryption or whatever around it was defeated so it is not "locked down" anymore. This is why there are engine\trans tunes for the LS430.

For some reason I don't remember the specifics now, but I don't think it's as easy as just putting a LS400 ECU in a Celsior. 97+ means immobilizer, which means you can't swap the ECU at all. I think 95+ USDM cars get OBD2 and international cars don't, I don't know how that interchange works with the port within the car and that cabling. I'm not sure if the radio and other electronics change, I think plugs may be changed but I'm not sure.

You're also talking about running a standalone ECU. Throwing out all the tuning, error reporting and drivability work Toyota did and starting from zero. Standalones like Megasquirt are great and they have a purpose, but I don't think you know what you're doing and I think this is an awful idea. UNLESS this is a junk\project car, then I say have at it.

Yamae

Celsiors use a hydraulic cooling fan. On the other hand LS400s use electric cooling fans. The cooling method alone is totally different and both the circuit and the software are not compatible.

Stroock639

the LS 400 uses a direct clutched fan for the main one, and there's just a single electric fan that only activates when it's hot enough outside and the A/C has been running... you're saying that second fan isn't electric on the celsior?

Yamae

The photo you showed is not a Celsior's. It must be for non-JDM LS400 or SC400.
A Celsior has a big hydraulic fan only and it doesn't have any other fans. The hydraulic motor gets the controlled pressure generated by the hydraulic pump attached to the engine. The pump is precisely controlled by the ECU changing the pressure.

Stroock639

oh interesting so on the celsior that fan with the clutch isn't there? but yes that's a non-JDM 1UZ

Yamae

A Celsior does not have a fan with the clutch. The hydraulic fan controls everything even the A/C is ON. When idling, you even can stop the rotation by your hand since it is rotating very slowly but once the engine becomes hotter or the A/C is on, the rotation speed increases a lot and you can hear the sound of air blowing but not so noisy to me. I'd say the cooling system for my Celsior is very well made. We never had any trouble with it during my brother's owner ship and mine for more than 2 decades. We never needed to add the fluid nor to do any maintenance. Both functions and the reliability are excellent.

So when someone uses Celsior's ECU for non Celsior, the cooling control system has to be dealt with deeply. I'd say it's not easy for an average DIYer. Only someone very well skilled can do it.

You can see the cooling fan here. The hydraulic motor is this and there are ports of in and out indicated by arrows.

Stroock639

that's awesome! i never knew about the difference in the cooling system... i love learning about all the little variations between the multiple international markets the LS/celsior was sold in

any idea why it was done this way? are there any other significant mechanical differences like this between JDM and non-JDM models?

Yamae

Regarding the hydraulic cooling fan, I was informed from an engineer who was related to the cooling system, "Aimed the best NVH in the world and the best temperature controlling performance at any places in Japan where the climate is extreme".

According to the manual, it says below in Japanese. I just add the English translation under this but sorry for my limited skill.

■電子制御油圧駆動ファン
ファン騒音の低減のため、新開発の電子制御油圧駆動ファンを採用しました。ファンの回転数を無段階にコンピュータ制御して常に最適な風量が得られるようにしています。
このシステムは、タイミングベルトで駆動される専用オイルポンプによる圧送されるオイルで、ファンに直結した油圧モーターを駆動しています。
制御コンピュータは、エンジン回転数、冷却水温、エアコン信号により、オイルポンプ吐出側の制御バルブを調整して油圧モーターへのオイル量を調整し、クーリングファンの回転数を調整します。
油圧モーターを通ったオイルは、オイルクーラーで冷却されて、再びオイルリザーバタンクに戻ります。

(English translation)
■ Electronically controlled hydraulically driven fan
In order to reduce fan noise, we have adopted a newly developed electronically controlled hydraulically driven fan. The fan rotation speed is controlled steplessly by a computer to ensure that the optimal air volume is always obtained.
This system uses a hydraulic pump driven by a timing belt to drive a hydraulic motor that is directly connected to the fan.
The ECU uses the data of engine speed, cooling water temperature, and air conditioner signals to adjust the control valve on the oil pump's discharge side to adjust the amount of oil to the hydraulic motor and the rotation speed of the cooling fan.
The oil that passes through the hydraulic motor is cooled by an oil cooler and then returned to the oil reservoir tank.

As far as I know about other differences, the gear ratio of the AT is slightly different and the evaporation control system is quite different due to the strict regulation especially a model for California.