Key On/Engine Running (KOER) Test

This test checks sensors under actual operating conditions. Fault must be present at time of test to be detected. This test will display an Engine ID Code, a Dynamic Response Code and an On Demand Service Code. After a Dynamic Response Code is received, quickly press and release accelerator once only. If test is not performed properly, a series 70 code (77, 76, 73, 72) will appear and the test will have to be repeated.

Start and run engine at more than 2000 RPM for 2 minutes. Ignore any output codes at this time. Turn engine off and wait 10 seconds. Verify test is activated. Start engine. Test will proceed with Engine ID Code, Dynamic Response code and Engine Running On Demand service codes. If a 10 or 1 pulse occurs during Dynamic Response code, open throttle wide open momentarily. Record codes and proceed as follows: