P0690 Buick Electronic Control Module Power Relay Sense Circuit High

P0691 Buick Fan 1 Control Circuit Low

Possible causes
– Faulty Low Speed Radiator Fan Relay
– Low Speed Radiator Fan Relay harness is open or shorted
– Low Speed Radiator Fan Relay circuit poor electrical connection
– Faulty Electric Fan
– Faulty Engine Control Module (ECM)
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Radiator fan inoperative
– Possible engine overheating
Buick Vehicle:Buick Regal – ?Buick Riviera – ?Buick LaCrosse – ?David Dunbar Buick – Buick Century – Buick LaCrosse – Buick LeSabre – Buick Lucerne – Buick Park Avenue – Buick Regal – Buick Verano – Buick Enclave – Buick Encore – Buick Rainier – Buick Rendezvous – Buick Terraza – Buick Riviera