Recommended Procedure

To perform self-test, turn ignition off. Ensure test equipment is properly attached. If vehicle is equipped with an auxiliary powertrain control system (RPM control), it must be turned off before performing self-test. Using NGS tester, perform the following steps:

Select VEHICLE & ENGINE SELECTION menu.
Select VEHICLE, YEAR & MODEL.
Select PCM - POWERTRAIN CONTROL MODULE.
Select DIAGNOSTIC TEST MODE.
Select KOEO ON-DEMAND SELF-TEST.
Turn ignition on.
Follow operating instructions from NGS tester menu.
Record DTCs and perform appropriate system test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 7.3L DIESEL article. After test has been completed, cycle ignition off before performing other self-tests or driving vehicle.

NOTE: If performing repeated self-tests on models with Federal emissions, disconnect glow plug relay to keep battery from going dead. Relay is located on top, right side of engine. Ignore any glow plug DTCs while glow plug relay is disconnected.