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P1620 Diagnostic Trouble Code Discussion for October 2009

Low Engine Coolant Switch Circuit Low Input

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Trouble Ticket Help Requests for DTC P1620
Help Request Posted
2000 Saturn SL2 1.9L Readiness Monitors VIN: 1G8ZK5272Y
P1620: low coolant circuit. Mil light works properly and goes off OK when vehicle is started. However, 3 readiness monitors will not complete. They are Catalyst, Secondary Air, and EGR. Have been driving this for weeks - no difference???
October 05, 2009
2002 Saturn SC1 1.9L Hesitation, Cuts out, Stall VIN: 1G8ZP12862
P1620: low coolant. vehicle came in with above codes and egr valve connector disconnected. codes cleared. egr commanded % not matching actual egr %. egr replace with new a/c delco egr valve. vehicle test driven. idles perfect. under accel will kick and buck like a horse no matter...
October 27, 2009