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WARNING: This page is about a different car, the 2001 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.

General conditions for this trouble code: Atmospheric pressure must exceed 72 kPa and the engine coolant and intake air temperature must exceed -7°C.
Test 1: Engine running. Main relay voltage exceeding 10V. Pre -heating active.
Test 2: Engine running. Main relay voltage exceeding 10V. Pre -heating active for more than 60 s.