Voltage from ECM to CCCI

[good2win22]

I've been doing some research about code 41. I haven't had this code pop up but it got me thinking about the code 16 on the TR6 that did rear its head.  I'm still waiting for Bob to get to my TR6 module. 


Code 16 on the TR6 - cam sensor signal lost
Code 41 on the ECM - cam sensor failure


From what I've read when setting the cam sensor, the voltage from the the middle pin on the connector will be between 5 - 10 volts and then will drop to 0 - 2 volts when in the window of the Hall effect sensor. I've also read that to set the code 41 on the ECM, voltage coming from the sensor drops below 6 volts.


I found the diagram for the ignition module and started probing with my volt meter. All conditions are the same, battery is on a 2 amp charger, key is on.


I have 12.46 volts at the battery
I have 11.52 volts at pin P. This is the power coming from the ECM fuse and ignition circuit
I have 11.52 volts at the at the power side of the cam sensor and pin n at the ignition module
I have 4.97 volts at the middle signal wire at the cam sensor and at pin k at the ignition module


I did a resistance check on the grounds of the module, ground wire at the sensor connector and the brackets of the module.  The highest reading was a .04 with the voltmeter set at 20.


I guess I have several questions with this. First, obviously the age of the wire and possible corrosion of the contacts in the ignition circuit would cause the volt drop from the battery to the CCCI but what is the correlation of the voltage from the CCCI to the 5-10 volts at the sensor?


Second, why haven't I popped the code 41 sense the voltage is below the 6 volt threshold at start up?  I guess I need to check voltage while the engine is running to verify/confirm what voltage is.


Third, would the ECM go into batch mode without throwing the code?

[Steve Wood]

Your voltages sound about right.  Clean the fuse block contacts on the ecm-ign and ccci fuses and see if that helps reduce the drop.   there are lots of connections between the battery and module.  I don't think you have a problem.

[good2win22]

Cleaned the contacts at the fuse block on both circuits. No change.  Grabbed my spare ECM and swapped that in and I now have 11.89 volts at the ignition module and sensor but still the same 4.97 volts from the sensor. 


Bob sent me a message says that he can't duplicate the problem on the bench. Says he's going to throw it on his car later today and see what happens.  We'll see...

[Steve Wood]

the voltages will come up when the engine is started, I am pretty sure.  That will eliminate the question of voltage.  the 4.97 is about normal as I recall.