MoTeC Global Forum

Hi,
I have a Motec M48 ECU 9804 Serial 655 EPS C3, and a Motec TTB installed on my 1995 Holden VS Calais V8 383.

As part of the installation it looks as though some engine functions of the diagnostic connector, and the "Check Powertrain" lamp on the dashboard, have been disabled. An alternate LED equivalent for the "Check Powertrain" lamp has been installed near the OEM Holden powertrain control module. This LED indicates that the following Diagnostic Trouble Codes (DTCs) have been logged:

DTC15 - Engine coolant temperature sensor - signal voltage high
DTC23 - Input air temperature sensor - signal voltage high
DTC41 - Ignition electronic spark timing circuit fault

Am I correct in assuming that the above DTCs are logged because the Motec M48 is capturing and/or providing these functions, and that the "Check Powertrain" light has been disabled and LED installed to avoid the light being on all the time when in fact there is no problem? Or has something gone wrong with the installation?

I would appreciate any advice and recommendations you can give me.

Hi,
It really depends on how the M48 has been installed. I assume it is "piggy-backed" onto the factory ECU? Or has the factory ECU been completely removed?

You probably need to talk to the person who did the installation. Normally with an M48 piggy back we would get an extra Air Temp and Coolant Temp sensor installed to keep the factory ECU happy but this may not be how your car has been done. The ignitino system fault would be expected because the M48 will be incharge of that and the factory ECU is missing it.

I am not sure why there is an alternate diagnostic LED in there. Maybe the factory dahs one has been connected to the M48 as a shift light...?

There are many different and equally effective ways to install an ECU, especially piggy backed.