Swallowtail

Hi guys,

I'm jusing the T-OBD Scantool which tells me my Mototronic has fault code "44 - Tank ventilation valve".

Is this the same as fault code as P0444?

samurai_k

If you go to the Factory service manual: DME Diagnosis "book #24" you will find a section that explains the error code 43 as well as the procedure to test the valve.

It is #3 in the picture below. Screen shots of the service manual sections as well.

samurai_k

I have not tried it yet, but from what I remember both the durametric and the UDT999 OBD apps allows you to activate the valve as described as the "drive link" above.

Swallowtail

Thank you! I will report back in the other thread

pp000830

My Factory printed list of codes does not list a 44 for a 993 as a valid code.

• A 45 is a valid code derived from the conclusion that the CAT is not working properly, diagnosed by the after CAT oxygen sensor.

• A 93 is listed as "Fuel Tank Ventilation System P0441"
• A 98 is listed as Fuel Tank Ventilation Valve P0444 or P0445 or P0445

Am I missing something here?
Andy

Swallowtail

Maybe a wrong attribution in the Rennlist Scantool? Output is definitely as described (no typo).

pp000830

Wow, the two-digit code is a raw code provided by the Motronic system so there is a communication error, some additional codes were added on later year cars I am unaware of or it is a clipped part of a "P" four-digit code on the display of your scanner. Your scanner would have to be a very sophisticated to list a specific "P" codes as it would need to take into account the Malfunction Indicator Light MIL (Check engine) and the memory state in the ECU to diagnose to the four digit "P" code
For any given 2 digit fault code in combination with one of the below 4 states will point to one specific "P" code that relates to it.
0 MIL is not triggered with this fault
1 MIL is on and Freeze Frame is stored in memory
2 MIL is on and a previous Freeze Frame is overridden
3 MIL is blinking and a previous Freeze Frame is overriddenIL Light and memory status states:

Andy

Swallowtail

I'm very sorry but I made a mistake. I just read it out again and it indeed says 43 - not 44.

I do not know how 44 got stuck in my mind - I was so sure

pp000830

I must be missing something in that I do not show 43 as a valid code on my factory-supplied document dated 1996 named "On-Board Diagnosis 911 Carrera (993) Trouble Codes". It is listed as a valid Porsche Code on a third party site but possibly not for a 993.
Here it is:

Swallowtail

Here is a screenshot from the scantool. Problem is solved now - it was indeed a not connected plug to the valve.

Thank you both for your help!

Swallowtail

I checked my version of the manual. The code is present - maybe it is only valid for the non Varioram cars. (Same thing Samurai postet earlier)

pp000830

Interesting,

I checked the lists they don't match in some descriptions for the same numbers that are on both lists:
Maybe the earlier non-Varioram non-OBDCII Motronic ECU has a completely different code set that was changed and remapped to meet the 1996 USA DOT/EPA OBDCII standard code list required by US Regulation.
Andy