A lockup kit is a very popular mod for the 4WD tourer and off-road adverturer, especially in the LC200 and now Prado/Hilux/Fortuner. It reduces fuel consumption and transmission temperatures, improves engine braking, and gives better power responsiveness.
[edited 14/04/23 to include Prado 150/Hilux/Fortuner as lockup-matePLUS+ now support these models and has the same design and features as the LC200 described below]
One of the questions I’m frequently asked is
“How does lockup-mate®PLUS+ work and how is it different?”.
Firstly, I’d like to answer this by providing a brief introduction to the various types of lockup kits available for the Landcruiser 200, followed by an explanation of the advanced features of MM4X4 lockup-mate®PLUS+, which has features and intelligence only possible due to its digital control interface to the vehicle ECUs.
lockup-mate®PLUS+ is the latest product release from MM4X4. Designed, manufactured and supported in Australia, with lifetime firmware updates available as new features or improvements are added.
Evolution of Automatic Transmission Torque Converter Lockup Kits
First-generation lockup kits are a simple on/off button, controlled entirely by the driver. Typically, the driver would switch the kit on at cruising speeds and manually switch it off again to unlock as the vehicle slowed. Failing to unlock can cause the engine to stall which puts a lot more responsibility and mental load on the driver, as they rely on the human for all lockup control.
Second generation kits simplified the operation for the driver by automatically locking and unlocking the torque converter at a pre-determined speed. Typically, there is a high and low speed switch. The high speed setting is often used with the transmission in DRIVE, and the low speed setting when the transmission in SPORT. Some kits automatically switch between high and low speeds according to the DRIVE or SPORT position. Speed-based automation was a leap forward in ease of use, but in SPORT mode and in the low speed setting, the driver must always keep on top of the gear choice. Failing to change gears at the right time can cause stalling, engine error codes, surging and harsh gear changes. This puts more responsibility on the driver to use the kit appropriately.
The next generation lockup kit is the digitally controlled lockup-mate®PLUS+ (or LM8+ for short in this blog). It is specifically adapted for each Toyota model and transmission to provide the best performance for that model.
It’s not just about locking the torque converter. lockup-mate®PLUS+, intelligently locks and unlocks according to the actual conditions, for a smoother driving experience and to protect the transmission.
It's fully automatic, so it’s easy to use. You just drive the car like normal. Use D around town (60kph), or S4 if you want it to lockup. To lockup at lower speeds (from 25kph) you simply select a lower gear (S2, S3). For highway driving just use D, S5, or S6. It also adjusts for 4H and 4L fully automatically. Easy!
You can also turn the kit on and off with a push of the LED/switch. When in 4L and using momentum to clear obstacles, we advise that you disable the lockup kit. In this situation the torque converter helps to reduce driveline shock loads.
All the features described below are not available in a ‘speed-based’ or manual button lockup kits.
What is digital control?
Digital control uses a computer to communicate with the vehicle Electronic Control Units (ECUs) and intelligently controls the use of the lockup clutch. This makes it very easy to use and provides an enhanced driving experience, whilst protecting the transmission from damage and excessive wear.
A speed activated lockup kit does just, and only that. It measures the vehicle speed by intercepting the speed sensor wires from the transmission and locks up the torque converter above that speed, regardless of the overall status of the vehicle (eg, under full throttle).
A digital lockup kit, instead, obtains information from the vehicle ECUs using the vehicle’s digital CANBus network. This also makes it much simpler to install.
lockup-mate®PLUS+ communicates with the Engine ECU, Transmission ECU, Instrument Cluster ECU (and more) via the vehicles OBD2 diagnostic connector.
The LM8+ control unit processes not only speed, but also throttle position, current gear, RPM, transmission shift lever position, selected Sport gear number (eg S4), torque converter slip, transmission oil temperature, high or low range 4WD (4H/4L), headlight status, cruise control, and more.
It also measures the ECU’s electrical current to the torque converter solenoid, and uses digital PWM control of the torque converter solenoid to mimic the complex control signals of the factory computer.
With all this information available, lockup-mate®PLUS+ can seamlessly and properly integrate with the operation of the vehicle.
Drive & Sport Operation
When the torque converter is locked, the driveline is like a manual gearbox with a direct connection between the engine and wheels (no slip). In an automatic transmission the factory ECU gear up-shift points are programmed such that it will typically select a gear which is too slow to maintain lockup. This is a key behaviour that impacts the operation of a lockup kit.
LM8+ uses different lockup logic for DRIVE, SPORT and low range 4WD (4L).
DRIVE
When in D, S5, and S6, the ECU will leave the car in 5th gear at speeds as low as 50kph, which is too slow to maintain lockup.
So in D it will lockup when above ~70kph. 70kph is a guide, not a rule, as all the protection logic still applies.
To get the most benefit from the lockup kit at lower speeds, a lower gear is necessary, hence the use of SPORT mode, eg, to lockup at 60kph, use S4.
You can also use D when you only want it to lockup when driving in higher speed zones (eg. 80+kph).
SPORT
In SPORT mode, LM8+ uses a more complex algorithm to intelligently lockup the torque converter. As mentioned before, the transmission will often change gears too early to maintain lockup, and the kit needs to accomodate this.
So LM8+ includes the actual gear shift map from the factory ECU to constantly predict ahead in time to determine if the transmission will change gears. Combined with speed, gear, accleration and throttle position, LM8+ will only commence the lockup process if it can remain locked if the gear changes.
A difference between the two LC200 models is the programming of the transmission gear shift points.
LM8+ includes the factory gear shift profiles for the LC200 models and uses it as part of the lockup control logic for each model.
Low Range 4WD (4L)
In low range the lockup algorithm primarily uses RPM (locked equivalent) when controlling lockup. The lock and unlock RPM ranges are adjustable depending on driving conditions. When climbing you may chose lower RPM range than when driving in sand. However, for most situations the defaults are fine.
To Lockup or Not to Lockup? That is the question
The torque converter is an amazing mechanical device which allows you to sit stationary while idling and then provide torque multiplication while accelerating. There are times when it’s best to use the torque converter, and times when its best to keep it locked.
lockup-mate®PLUS essentially changes the factory lockup profile, but in an intelligent way. It prioritises the use of the torque converter clutch for the fuel saving, temperature protection, and engine braking benefits, but will still unlock it when the conditions require it - fully automatically.
For example, if you are at low RPM there is less engine torque available, when extra power is needed the transmission can either unlock the torque converter or downshift a gear. LM8+ will assess the conditions and decide if unlocking is the best action to take.
Working in Harmony with the Transmission ECU
Because lockup-mate®PLUS+ communicates with the ECUs, it understands their status. In particular it knows when the ECU is controlling the lockup clutch in either the fuel saving flex-lockup mode or full lockup mode. When the ECU is using flex-lockup mode for fuel savings under light throttle, lockup-mate®PLUS+ will hand control of the torque converter back to the ECU. Similarly, when the factory ECU wants to fully lock the torque converter LM8+ will relinquish control. The means the factory ECU and LM8+ are both controlling the lockup clutch together, in harmony.
lockup-mate®PLUS+ will only control of the torque converter when it needs to override the factory ECU.
This also means the load resistor doesn’t get hot, which would occur if the lockup kit and ECU are both wanting to drive the solenoid at the same time.
Transmission Protection
SafeLock® is exclusive to MM4X4 kits. A limitation of a 'speed only' based lockup kit is they will lock according to just the vehicle speed, so under high load conditions this will activate the lockup clutch even when the slip is very high. Similar, if the torque converter remains locked at very low RPM there isn't enough pressure to hold the clutch firm. This can cause unnecessary wear to the torque converter clutch plate.
Our SafeLock® feature is constantly calculating and monitoring the slip in the torque converter, and will not activate the lockup clutch until the slip is low. For maximum longevity and reliability of the clutch it uses the same slip limits as the factory program.
Of importance is not only when to lockup the torque converter, but also when to unlock it. There are times when its best to unlock for a smoother gear change. For example, under low RPM (<1400), if the transmission downshifts from 4th to 3rd under high load, it will unlock to avoid a harsh gear change. Furthermore, at low RPM is automatically unlocks to prevent clutch slip and exccesive wear.
Also, when coasting ‘unlocked’ at low RPM there isn’t enough line pressure to apply the clutch. lockup-mate®PLUS+ recognises this and won’t lockup until the RPM is at least 1800. Once locked, however, it can remain locked until ~1300rpm.
It also monitors the transmission oil temperature and avoids activating until warm, just like the factory program.
Emergency Braking Unlock
All of our kits include the feature of immediately unlocking the torque converter when emergency braking (regardless of the speed). This reduces the chance of damage to the transmission should an impact occur. It also avoids the potential of interferance with the vehicles safety systems, like ABS and stability control. This is another protection feature which is unique to our products.
Advanced PWM Control
An essential element of a lockup kit is powering the electrical solenoid which controls the application of the torque converter clutch. This solenoid is a proportionally controlled valve that is adjusted by the characteristics of the Pulse Width Modulation (PWM) signal.
A 0%, 25% or 50% PWM signal will change solenoid position and thus the pressure against the torque converter clutch plate. This is exactly the same concept as releasing the clutch pedal when driving with a manual gearbox. Either you gently release it for a smooth takeoff, or alternatively ‘drop the clutch’. Basic PWM control would apply 0% then 100% and does not ensure smooth engagement.
The factory PWM engagement profile of the lockup clutch is a complex process that can take up to 4 seconds before full engagement is achieved. lockup-mate®PLUS+ digitally controls the PWM signal in the same way as the factory ECU so engagement of the clutch is smooth.
No Engine Trouble Codes
The transmission ECU has advanced real-time diagnostics and is continually looking for anomalies. If a problem is detected it will generate trouble codes (eg, P2757), which is actually just a 'false alarm' when a lockup kit is in use . This causes a Check Engine Light (CEL) and will disable some vehicle functions like the pre-crash warning system and ASC.
To date, the typical solution an engine re-tuner adopts is to reprogram the ECU to disable the CEL for the P2757 . However, LM8+ works in harmony with the ECU and will instead automatically clear a specific engine code (if necessary) by communicating with the ECU.
No reprogramming of the vehicle ECU is needed to avoid a Check Engine Light
But a CEL could also be caused during installation if a plug is not connected (code P2759).
So a new feature we're adding across our range of products is to clear the CEL. lockup-mate®PLUS+ will send the OBD2 standard command to Clear the Engine Light using a simple double-click of the LED/switch.
This feature is also handy if a CEL is caused by any vehicle problem and you just want to try clearing it. You don’t need have an OBD2 reader or be an expert in using one.
Configuration Settings & Self Diagnostics
lockup-mate®PLUS+ is adjustable so you can set it up to your vehicles configuration or personal preferences. You don’t need to access the control unit to change its settings, instead, it communicates with the transmission ECU and Instrument Cluster ECU to enable you to change the configuration settings and to run its self-diagnostics.
With the ignition on (engine off) and the shift lever in the S position, you just press the LED/switch to enter these modes. Changing a setting is a simple as moving the shift lever + and – and looking at the instrument cluster for the new value, then pressing the LED/switch to select the next parameter to adjust. Simple.
Prefer to go hardcore? We’ve tried to cater for all customer’s needs and you can even disable all the inbuilt protections (but we don’t recommend this of course).
OBD2 Reader Compatibility
lockup-mate®PLUS+ is designed to operate in conjunction with an OBD2 reader, such as an UltraGauge, ScangaugeII or smartphone with an app.
Pre-facelift 200 series (2007-2015)
In the pre-facelift model there is a simple the interface between LM8+’s computer and the vehicle. By decoding the Toyota unique CANbus messages, LM8+ can ‘sniff’ most information in real-time. This also enables simple sharing of the OBD2 interface with aftermarket OBD2 readers (like UltraGaugeMX, ScanGauge II, and ELM327 devices).
As a result, there are no compatibility issues using lockup-matePLUS+ and OBD2 readers in the pre-facelift LC200.
2015+
From 2015, however, Toyota made significant change to the electronics architecture across many models. The In some, the Engine and Transmission ECUs were combined, a CANBus gateway introduced, and the CANBus messaging system was completely redesigned. Similar changes occurred again in 2020+.
In 2015+ model, every piece of information must be requested from the ECU rather than ‘sniffed’ like the pre-2015 models. In order to operate with OBD2 readers the digital OBD2 interface must be shared with lockup-mate®PLUS+, a purpose for which the industry standard OBD2 protocol was never intended. LM8+ overcomes this by using complex multiplexing of data requests to avoid conflicts between the two devices.
Unfortunately, compatibility with OBD2 readers is now a consideration. Compatible OBD2 readers include the UltraGauge, ScanGauge2, ScanGauge3 and ELM327 (but only some apps are compatible). CarScanner, and UltraGauge Blue apps are ok, but TorquePro is incompatible as it doesn’t filter the message stream. CarScanner is a very good alternative to TorquePro.
When using an OBD2 reader with the 2015+ models, the data request rate should be set to the maximum value. Instructions are available from this page using the CHECK COMPATABILITY button.
OBD2 Diagnostics
The kit includes a Y-splitter cable so LM8+ and the other OBD2 device can share communications with the ECUs, however dual use of the OBD2 interface is intended only for OBD2 readers which simply monitor ECU parameters (like current gear, engine temp, trans. temp, EGT temp, turbo boost etc).
If the other OBD2 device is used for diagnostics or specific activities like ECU re-programming, the kit should be switched off to allow the other device exclusive access to the ECU.
When turned off using the LED/switch, all CANBus activity is suspended, so any OBD2 device can still be used.
Remote Touring and Built-in Fault Tolerance
We’ve spoken a lot about digital features, but what happens if it all goes wrong. We’ve come from a remote touring background know how important keeping your car running is, so fault tollerance has been designed in.
If you suspect a fault with the operation of the lockup-mate®PLUS+ you simply remove the OBD2 plug from the vehicle connector which removes all power and will deactivate it. The internal relays will revert the wiring to the factory setup.
You may also wish to do this before taking the car in for a dealer service.
And even if there is a fault with the internal relays, the kit includes a link plug. You just remove the connector from the control unit and install the link plug to return everything back to factory wiring. This plug is also used to return the vehicle to normal if the LM8+ control unit is returned to us for a firmware upgrade.
If the digital interface to the lockup-mate®PLUS+ computer is interrupted or an internal anomoly is detected, it immediately unlocks the torque converter and resets itself.
A Final Note
You can see that behind the simple blue status LED is a very intelligent logic system, only possible using computer control and digital communication with the ECUs.
It’s normal for the LED to come on and off while driving, and sometimes you may not understand why it might seem to stay unlocked. In some respects, you just need to trust that the kit is working in your best interests.
And on a final note, the kit also has a feature called Slip Alert. If after 20 seconds of sustained high slip in the wrong gear it will flash the LED to advise you to down-shift if you want to regain lockup. It even dims the LED when the headlights are on.
If you are considering purchasing lockup-mate®PLUS+ and still have unresolved question/s, please contact us via the website, and include your phone number if you want us to contact you.
Happy travels,
Marshall