DR-23 Throttle Body Minimum Air Flow

*** UPDATED BY TSB #18-61-86

1. Connect diagnostic read-out tool to engine test connector, then disconnect and plug vacuum supply hose to heated air temperature sensor.
2. Remove air cleaner assembly and connect tachometer to engine.
3. Disconnect tee connector in PCV valve vacuum supply hose, then install tool C-5004 or equivalent into vacuum supply hose.
4. Start engine and let it run until the radiator cooling fan cycles on then off, then put system into Engine Running Test Mode 70.
5. If tachometer is reading 1100---1300 RPM for 4-135 engines or 1050---1250 RPM for 4-153 engines, proceed to Test 24. DR-24A Driveability Not Related to Engine Controls
6. If tachometer is not reading specifications, replace the throttle body.