Toyota MA61 Supra Check Engine Light Install Guide


This page details one method of installing a Check Engine light into a Australian delivered MA61 Supra dash. Australian delivered MA61 Supra did not come with a check engine light fitted from factory, so when an engine conversion is undertaken and an engine with a check engine light is fitted it isn't possible to wire up the check engine light until some modifications are undertaken. 


Basic art skills are required and some proficiency with a soldering iron (this article assumes that you are able to remove the dash cluster/plastic cover without guidance, it is not a complex process).


I offer this article in good faith only; and accept no liability for damages incurred should you choose to follow this guide.


Installing the Check Engine Light Bulb

There is a spare location in the MA61 dash in which to install the bulb required to be the check engine light.  The circuit of the Check Engine light is that the ECU provides a ground to switch the check engine light on, and the other side of the bulb is supplied with a power source.


The power side of the bulb (if installed at the indicated position) is supplied by the dash with fused (Gauge Fuse), ignition switched power which is ideal for our requirements, however a wire from the engine ECU 'W' pin to the other end of the bulb is required. I'm not aware of a spare wire in the existing MA61 body wiring loom, so I installed the required wire from the engine ECU to the dash.


Installing the globe simply requires scratching/removing the solder mask from where the globe contacts sit as can be seen in the below picture (second position from the left).  I suggest acquiring the required bulbs at the same time as the Check Engine Light symbol if possible.


The other end of the MA61 dash circuit board doesn’t lead to a plug however, so I soldered a single pin plug to the track.  I removed some solder mask to allow tinning of that track, and then soldered the wire leading to a plug. Afterwards I applied some hot glue over the top to add some extra strength to the joint. NOTE: Be particularly careful during soldering as too much heat from the solder iron WILL cause the plastic dash membrane / circuit board to melt!  I also suspect it would be possible to disassemble that dash and install a screw etc similar to a number of the other existing connections; however this is not something that I looked into.


The above section covers the modifications required to the rear of the dash; however it is also necessary to fit a Check Engine light symbol as discussed in the following section.


Installing the Check Engine Light Symbol

The below picture shows the removed MA61 dash, the front plastic cover of which also needs to be removed.  The area of interest is the blank area directly to the left of the ‘BRAKE’ signal that can be seen in the bottom-centre of the dash.


The below picture shows the area that the Check Engine light will be installed into in more detail.  The Check Engine light is installed into the space between the fuel symbol and the BRAKE warning signal.


The following picture shows the removed portion of the dash light system (Note: I was unable to remove the panel without the two with mounting posts, but ideally the mounting posts would remain).  This acts as the template to which the Check Engine light is added.


I sourced my Check Engine symbol from a MZ11 Toyota Soarer however this is not an ideal candidate in my experience.  The plastic used in the MZ11 dash is slightly thicker and although it can be made to work, it does look slightly messy / rough (however this cannot be seen in the finished product, so is of no real consequence).  The MZ11 dash symbols are also uncoloured; they receive their colour by tinted covers underneath the symbols after the dash globes.  This means that if you wish for your Check Engine light to light up a colour other than white (yellow is the stock colour for Toyota Check Engine lights to my knowledge) you will need to add a cover to your globe or some form of tinting.  The below photo shows the MZ11 Check Engine Light symbol as sourced.


This picture shows the marking out process.  I suggest marking out such that you will be able to make the required joins under the plastic dividers between sections helping to hide any mistakes/imperfection in the joins.


The process of installing the Check Engine light requires cutting out of the blank area to the left of the BRAKE writing such that the Check Engine light symbol can be installed in its place.  A sharp cutting tool is required, I used as scalpel.  Once both the existing panel and the donor Check Engine symbol have been trimmed to the correct/needed sizes it is simply a matter of bonding them in place (NOTE: I found generic superglue to be ineffective, I used hot glue instead, however epoxy may work).  The below photos illustrate the procedure that I undertook.



The below picture shows the modified panel installed in the dash (NOTE: as I removed the two mounting posts I simply glued them back in place to secure the panel).


The below picture shows the completed MA61 dash with Check Engine Light illuminated.



Wiring of the Check Engine Light is not a complex process, simply one wire from the engine ECU is required to be routed from the engine ECU area to the dash area.


The engine ECU pin commonly marked as 'W' is the required engine ECU pin.  The engine ECU illuminates the Check Engine Light by grounding the 'W' pin as required.


For the Check Engine Light to come on there must be a power source at the other end of the bulb for the ECU to provide a ground for.  The Check Engine Light and accompanying diagnostic circuit can be seen in the below figure.


[Engine Controls Part #4 –Diagnosis, Toyota Motor Sales, U.S.A.,Inc.]



I would not suggest using a MZ11 Soarer dash as the donor dash.  I have done some more research into dashes and the most suitable donor I have found currently is from an RT142 Corona.

5M-GE MX73 Cressida is unsuitable as the symbol is too large (in my opinion).

RA65 Celica does not have a symbol, only writing which personally does not appeal to me as I prefer the symbol.


It maybe discover that there is an ideal donor dash; such that the existing panel can be replaced without modification, however I am yet to identify one if one does indeed exist. I have also seen Check Engine LED’s fitted to some export xA6x Celica / Supra / XX; pursuing this may also be an option.


Getting the engine ECU to 'flash out codes' is achieved by connecting the engine ECU TE1 pin (or the Tc pin on more modern Toyota engines) to the engine ECU terminal E1 (E1 is the equivalent of ground, which is also equivalent to the battery negative terminal). A Toyota document that provides more information can be found <here>.



As you can see, installing a Check Engine Light into a MA61 dash is not particularly hard!  Of course you must also remember to run the required wire from the engine ECU.