Xantia - How to Read Bosch MP5.2 Fault Codes?

wilsonkrg · Unread post by **wilsonkrg** » 24 Apr 2003, 14:57

I have a 1997 Xantia 2.0l 16V with a Bosch MP5.2 Engine ECU. After a bit of a fright yesterday (I think the MAP sensor went of hols for a while), I decided to get serious about trying to extract the fault codes for the ECU (like I can already do on BX M1.3 and AX Monomotronic ECUs). I found some instructions on the Yahoo boards - found the C3 terminal on the diagnostic connector and verified that it seemed to be connected to the ECU light in the dash by the way its voltage changed with the light going on an off.
However, after turning on the ignition and waiting for the ECU light to come on, shorting pin C3 to chassis for varying periods of time does not seem to have any effect. Shorting it to chassis before turning on the ignition had no effect either. I started the engine to make the ECU light go out, the grounded C3. This turned on the light by brute force and the ECU obviously recognised this as it held the light on for a few seconds after ungrounding. When the light went out again, did I notice a flicker? Checking with the oscilloscope revealed a 4mS off pulse about 80mS before the lamp went hard off. Does anyone know the significance of this?
Has anyone had more luck than me in being able to read the codes for this ECU using the in-dash ECU lamp? and if so how do you do it?
Regards
Ken W (Aust) [:(]

mbunting · Unread post by **mbunting** » 24 Apr 2003, 18:08

I wonder if you're closer than you think..
I have an ecu reader for Motronic 3.1, and you switch on for three seconds, off - then it starts to flash as you - repeat as required.
Have you tried a similar sequence with the Xantia using your technique ?
Mat.