Diagnostic Aids
WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
To locate an intermittent problem, use scan tool to monitor DTC P2600 LAST TEST with engine running above 1800 RPM or ECT above 178°F (81°C). Wiggling wires while watching for a change from PASSED to FAILED may locate the area where an open in the wiring may exist.
Auxiliary coolant pump relay coil resistance: 70-115 ohms.