I put my '09 C5 onto a diagnostic machine

[pentoman]

I borrowed a diagnostic machine and had a play with my "new" (to me) C5 today. I was just curious to see what was in there, what was available to change, how my values looked, and what faults may be stored if any.

Some screenshots are below for anyone interested.

The only significant logged faults under the 'engine' screen were to do with the brake sensor (possibly because the other day I used the accelerator while also lightly pressing the brake - oops!). None of these faults caused a dash warning to show up or any other negative effects.

I'm not sure how to interpret "EGR opening control applied". Should this match the value for "EGR Required opening position"?

There was a fault for the rear body height sensor which I cleared. The readings show the height sensor as working okay.









Specifically I was looking for any hints related to the vehicle's performance. It's a bit lethargic unless you really keep your foot down. However the readings for air flow sensor and turbo etc seemed "normal" to my untrained eye and there were no recorded obvious faults.

Hope this is interesting to somebody.

[pentoman]

Oh one more questions - would these fault codes (e.g. the rear height sensor) also have shown up on a generic/ebay OBD fault reader?

[Hell Razor5543]

Doubtful. Although car manufacturers 'agreed' to standardise the diagnostics communications, they didn't all do so. Anyway, the Lexia can tell you so much more than a simple generic reader.

[qprdude]

You say it's a bit lethargic, but you don't say what engine size/power you have. My 2.2 (173) is anything but lethargic,but I'm not sure I fancy a 1.6 in one of these big cruisers.

[pentoman]

Doubtful. Although car manufacturers 'agreed' to standardise the diagnostics communications, they didn't all do so. Anyway, the Lexia can tell you so much more than a simple generic reader.

Indeed and I do really want a Lexia but can't justify it when I have access to this diagnostic device. I hope this one (Autologic) does everything a Lexia does albeit at greater cost, since I spent an hour looking through every menu - there were hundreds covering everything from the Alarm's sensitivity to the stereo settings and depressurizing the hydractive. I can't think of anything that was missing - but then I've never used a Lexia .

Wishful thinking for a generic OBD reader to show those codes I guess.

You say it's a bit lethargic, but you don't say what engine size/power you have. My 2.2 (173) is anything but lethargic,but I'm not sure I fancy a 1.6 in one of these big cruisers.

My mistake. It is the 2.2 (173). It suffers from a poor throttle response. If you let off the accelerator at, say, 3000 rpm and reapply it, it takes a full two seconds for it to build up power again. Once the power has arrived it's very spritely, but it just takes so long for the power to arrive. I realise there is some turbo lag to deal with but I've driven a thousand turbodiesels and this seems to be among the worst for slow throttle response. It puts me off overtaking, because if I have to change gear during the maneouvre, I'll be floundering for two long seconds with no acceleration. Scary.

I need to drive or passenger in another one with the same engine, but am not sure how I achieve that (unless there's another friendly owner around Gloucestershire parts who wants some "beer tokens"!)

[qprdude]

The 2.2 seems a bit rare in the earlier X7 cars, as it was quickly replaced by the 2.0 I think. I have little, or no noticeably lag, and to be honest, one of the joys of the car is the superb overtaking power available instantly from 2000 revs upwards. Not to say that it's a slouch off the mark either. Not quite as rapid as my Saab, but a good balance for a big comfy cruiser. I think you might need a few tweaks somewhere.

[pentoman]

The 2.2 seems a bit rare in the earlier X7 cars, as it was quickly replaced by the 2.0 I think. I have little, or no noticeably lag, and to be honest, one of the joys of the car is the superb overtaking power available instantly from 2000 revs upwards. Not to say that it's a slouch off the mark either. Not quite as rapid as my Saab, but a good balance for a big comfy cruiser. I think you might need a few tweaks somewhere.

Thanks for writing that. What's it like when you change up a gear, is there a pause? Even if the new gear puts you over 2000 revs still?

[qprdude]

No pause or lag when I change up a gear, very smooth and there seems a continuous supply of power. I know exactly the feeling of a delay in power when you change up, as I had a Rover 75 with the 2 litre BMW derived engine which suffered from that. If I remember correctly it was something to do with the MAF sensor, but I couldn't be positive about that.

[wheeler]

Doubtful. Although car manufacturers 'agreed' to standardise the diagnostics communications, they didn't all do so.

I believe that was only for engine management & emissions related diagnostics so other systems like suspension, body control modules & autoboxes don't need to be standardised.