Hi, I have just started on TGO and would like to know if anyone could help me with the following question?

I have just replaced the ecm with a reconditioned item which now shows code 14 cts problem, now this comes up as a ses light soon as it goes closed loop, which is much quicker than the previous ecm, I have checked the voltage across the cts when this happens and its reading about .8 volt, the coolant temperature is normal which I would have thought would be around 1.5v or so, I think the unit may be the problem as the light is not on when the other ecm is fitted.

I fitted the cal pack / prom from the previous ecm (Hypertech)

The cts has been changed just to be sure.

Looks like it's the ecm, just wondering if anyone has had a similar thing happen?

Thanks!

 

Sounds to me that the replacement ECM is bad.

Pin C10 on the ECM is the CTS input. Check that the pin doesn't have any dirt or corrosion on it.

RBob.

 

Thank you RBob, I think its the "new" ecm as well, its all a bit of a hassle shipping it back ( I am over the pond!) and I have one that works at the moment.

Be nice to have the ATE to find the fault , although these are old now , not sure of how many have upgraded to the newer ecms on these first ones.

Mossie

 

May be able to fix it. Most likely there is a 348/3.65K pull up (PU) pair in series, and a 10K in series after that going on to the ADC.

The PU pair are in series going to +5 volts. And then either a transistor or gate that can be enabled to provide +5 V to the point between the two resistors.

This way the ECM can switch the PU between 4K and 348 ohms.

It may be something as simple as an open resistor.

RBob.

 

Thanks for that RBob, I will have a look!

 

This is from a different ECM, but is along the lines of what I would expect in the '85 TPI ECM.

RBob.

 

Thank you for that info, that will be a great help Sir!

mossie