Component Testing

Relay Test

1. Ignition/Vehicle - Off
2. Remove the component : KR121A Reductant Control Module Relay 1orKR121B Reductant Control Module Relay 2
3. Test for 70 to 110 ohms between the test points : Component terminal 2/85 & 1/86
   • If not between 70 and 110 ohms 

     Replace the component : KR121A Reductant Control Module Relay 1orKR121B Reductant Control Module Relay 2

   • Go to next step : If between 70 and 110 ohms 
4. Test for infinite resistance between the test points :
   • Component terminal 3/30 & 2/85
   • Component terminal 3/30 & 1/86
   • Component terminal 3/30 & 5/87
   • Component terminal 2/85 & 5/87
   • If less than infinite resistance 

     Replace the component : KR121A Reductant Control Module Relay 1orKR121B Reductant Control Module Relay 2

   • Go to next step : If infinite resistance 
5. Connect a 3 A fused jumper wire between the test points : Component terminal 2/85 & 12 V

   Connect a jumper wire between the test points : Component terminal 1/86 & Ground

6. Test for less than 2 ohms between the test points : Component terminal 3/30 & 5/87
   • If 2 ohms or greater 

     Replace the component : KR121A Reductant Control Module Relay 1orKR121B Reductant Control Module Relay 2

   • Go to next step : If less than 2 ohms 
7. All OK.