Intermittent safe mode and no codes

[alexk]

Hi, I'm getting safe mode occurring (when I restart the engine it goes away).  Have scanned for faults but nothing comes up. If safe mode is engaged should'nt the ecu have some record if it? The last fault I read was to do with the injector quantity adjuster which I haven't managed to investigate yet.

[insanitybeard]

I'm not sure what the issue might be but the ECU will only log a fault code if the various signals from the sensors that it uses/monitors fall outside of an expected range, therefore if whatever's causing the fault isn't throwing the sensor readings sufficiently out it won't log a fault.

E.G, if it was due to a drop in fuel pressure due to something like a split diaphragm then it could cause a loss of performance but not necessarily log a fault code if there isn't a sensor to 'see' the loss of pressure.

[alexk]

I see your point but isn't limp mode something that the ecu initiates due to recognising a fault? I assume it is limp mode I'm getting as the normal performance (full power) resumes when the engine is restarted.

[alexk]

Hi, I'm getting safe mode occurring (when I restart the engine it goes away).  Have scanned for faults but nothing comes up. If safe mode is engaged should'nt the ecu have some record if it? The last fault I read was to do with the injector quantity adjuster which I haven't managed to investigate yet.

[insanitybeard]

I see your point but isn't limp mode something that the ecu initiates due to recognising a fault? I assume it is limp mode I'm getting as the normal performance (full power) resumes when the engine is restarted.

It depends- is it definitely going into an ECU induced limp mode or is it an (engine) power loss caused by e.g, loss of fuel pressure, loss of vacuum somewhere, an intermittent electrical fault.....

Usually these kind of faults will be picked up by the ECU when a sensor reading goes outside of the expected perameters but not always. For example, the relay 109 fault on the diesels can cause (electrical) power loss to several systems but won't register a fault.

[alexk]

I assume it's limp mode as normal function returns when the engine is restarted. Is there anything else that could be 'reset' by turning the engine off?

[Chrispb]

Are you still getting a fault code for the quantity adjuster?

Just thinking your setup is not picking up codes that are present.

Test your VCDS set up by inducing a fault code, disconnect MAF sensor multiplug then start engine this will give you a code for MAF sensor short to +

Boost issues will leave a code whether it's pos or neg deviation that's 17965 & 17964
Also Accelerator position sensor G79 can give codes 18047 and 00777

[alexk]

No I am not getting any fault codes now. Will try what you suggest and see what happens.

[alexk]

Hi Chris, finally got round to checking the vagcom and I don't think uts working properly alright. Pulled the maf out with the engine running and got no fault codes from the vcds-lite. I also tried to reset the quantity adjuster as part of trying to sort out this intermittent limp mode problem. Got to the point where I entered new values and heard the engine tone change but was unable to save the changes as it said I needed the registered version to do that. Anyway am not sure it would have solved the problem if the adjuster is sticking.
Question is: can I  do anything to the vcds so that it will pick up the fault codes properly?

[Chrispb]

Have you checked the settings below.
https://www.fordmpv.com/smf2/ford-galaxy-reference-library/vagcom-vcds-lite-connection-problems/

[alexk]

Hi chris, I tried to reset the latency as per instructions but in my device manager (win 7) I was not given the option, only input and output rate. Output was at 16 and I reset it to 2 and the input level followed automatically to 4. When I connected the lead to the car the interface was found but there was a message that was 'poor'. Still no fault reported on vcds.

[Chrispb]

A lot of the cables from ebay only work with XP are you sure yours is OK for Win7

[alexk]

Dammit! Just checked my eBay history from May 2013 and it is indeed a cable for xp only. That explains some frustrations