Hi,

I am looking for pointers on the above fault.

The 3rd Piston Deactivation solenoid on a Bosch CP1 should be energised at idle according to the CP1 manual.

I have a Lexia trace from 2.5 years ago where it says it is active ie YES. There was no DTC back then.

About 1.5 year ago, I ended up doing a Frankenstein repair to the ECU. It doesn't seem to be in the area of where I need to be looking.

So symptoms are I can actuate the solenoid with a diag tool and can hear it clicking on and off for around 12 seconds. This proves the wiring and the solenoid is sound. To double check, I measure 23 Ohms across Pins 1 and 2 of the solenoid. To triple check, I graphed the fuel pressure whilst using a power probe to actuate the solenoid. I could see that the pressure fluctuated (presumably because the fuel pressure regulator) is trying to adjust the rail pressure. I am happy to upload graph if anyone feels it might be useful.

It seems clear to me that the ECU is not switching the earth side to Pin 80 of the 88 pin connector.

I have traced this back internally and it seems to go to Pin 21 Output Q4 (from memory - perhaps need to double check) of Infineon TLE 4266G chip (which is an intelligent six fold low side switch). Pin 4 of this chip traces to Pin 23 of an Infineon B59233 chip (which the datasheet says is P7.4/CC28IO?). From what I can make out, this is programmable as either an input or an output. I am assuming (which is dangerous) that Output Q4 on the TLE chip is fed from the Input IN4 on the opposite side of the chip according to the block diagram if I am reading it correctly.



This is probably a step too far to me but I am willing to listen to advice on how I can check component level for Pin 80 of ECU connector being switched to ground.

If this is outside the scope of this forum, I'd be interested to know of other websites / forums where I might be able to get an answer.

Part of me wonders if the programming has become corrupted somehow and the actual ECU hardware is fine?

If the above is correct, should I be looking at the file at the following address for CAPCOM2 CC28 to look for some particular HEX Code?



Thanks in advance.

I am a beginner who knows very little but am trying to make sense of it all so go easy on me please.