Component Testing

Relay Test

1. Ignition OFF, disconnect the KR121B Reductant Control Module Relay 2.
2. Test for 70 - 110 Ω between terminals 85 and 86 of the relay.
   • If not within 70 - 100 Ω 

     Replace the relay.

   • Go to next step: If within 70 - 100 Ω 
3. Test for infinite resistance between the following terminals listed below:
   • 30 and 86
   • 30 and 87
   • 30 and 85
   • 85 and 87
     • If less than infinite resistance 

       Replace the relay.

     • Go to next step: If infinite resistance 
4. Install a 20 A fused jumper wire between relay terminal 85 and B+. Install a jumper wire between relay terminal 86 and ground.
5. Test for less than 2 Ω between terminals 30 and 87.
   • If 2 Ω or greater 

     Replace the relay.

   • Go to next step: If less than 2 Ω 
6. All OK.