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PCM System Error: Navigation System not available


PCGB Member
Hi All,

I am looking for some advice/repair options for an issue with the PCM 2.1 in my 2006 997 C4S . Following a battery disconnect the PCM displays a message ' System Error: Navigation System not available. Under the SW versions screen (4.0) There is a warning triangle for the Navigation System. PCM, System Software, Amp, CD Changer and Phone all have a tick.

Selecting Navigation system displays a table that shows the Target: / Actual:------/------ Entered Yes Found No.

The DVD drive powers up and the disc spins, I have tried a reset on the PCM, disconnecting the battery, re-connecting the MOST bus but still the same issue.

The navigation system worked before the battery was disconnected.

Any ideas/options to remedy?

Thank you in advance for your help!



On the face of it that sounds like a MOST bus (fibre optic ring) issue. Usual course of action is to get a loop connector from Amazon and unplug / loop stuff until the error goes away but since it happened post battery change there is a chance a handover reset may be required ( needs Porsche PIWIS diags )

But. Since you said “disconnect” that suggests you/ someone was in the frunk around the battery. That’s where the amp and the auto changer (if you have them) are so I would suggest “checking your homework” in that area - especially looks for displaced or damaged “orange wires” (they aren’t wires - they are glass )

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