Output State Diagnostic Test Mode (DTM)

Output state DTM is used as an aid in servicing output actuators associated with EEC-IV system. It allows technicians to energize and de-energize most system output actuators on command. This mode is entered from KOEO SELF-TEST after all codes have been retrieved.

Disconnect cruise control servo (if equipped). With DVOM on 20-volt scale, connect DVOM negative lead to STO/MIL terminal at Diagnostic Link Connector (DLC). See Figure . Connect positive lead to positive battery terminal. Connect a jumper wire from Self-Test Input (STI) pigtail to Signal Return (SIG RTN) terminal at Diagnostic Link Connector (DLC). Turn ignition on.

Perform KOEO SELF-TEST  until continuous memory test is complete. DVOM will read less than 1.0 volt when test is complete. Depress and release throttle. If voltage increases, output state DTM has been entered. If voltage does not increase, depress throttle to WOT and release. If STO voltage still does not increase, go to CIRCUIT TEST QC. See the TESTS W/CODES - EEC-IV (2.0L) article in the ENGINE PERFORMANCE section.