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

P0691 Description

The Engine Control Module (ECM) has detected a short to ground in the cooling fan relay 1 control circuit

P0691 Information for specific makes

P0691 AUDI
P0691 BMW
P0691 CHRYSLER
P0691 DODGE
P0691 JEEP
P0691 SUBARU
P0691 SUZUKI
P0691 VOLKSWAGEN