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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 47 (Engine Controls - Tests W/Codes - 5.9L Diesel) >> Self-Diagnostic Tests >> Test TC-12A - Auto Shutdown Relay Control Circuit

Test TC-12A - Auto Shutdown Relay Control Circuit

WARNING: This page is about a different car, the 1995 Dodge Pickup and 1995 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit and connector terminal identification, see CONNECTOR IDENTIFICATION  . For wiring diagrams, see WIRING DIAGRAMS  section at the end of this article.
  1. Using scan tool, erase DTCs and actuate ASD relay. If relay is not clicking, go to step 3). If relay is clicking, condition required to set DTC is not present at this time. AUTO SHUTDOWN RELAY CONTROL CIRCUIT DTC sets if ASD and fuel pump relay control circuit is not in its proper state when monitored by PCM during cranking. Possible causes are: open or short in ASD and fuel pump relay control circuit, open or short in control circuit wire, open or shorted ignition power feed to relays, or failed control circuit driver in PCM.
  2. Inspect wiring and connectors. Repair harness or connector as necessary. Perform TEST VER-1. If no problems are found with wiring and connectors, wiggle harness between PCM and relay. Ensure actuator test is still running. Using scan tool, read DTCs. If AUTO SHUTDOWN RELAY CONTROL CIRCUIT DTC resets, repair appropriate harness or connector. Perform TEST VER-1. If DTC does not reset, see INACTIVE DTC CONDITION  . Test is complete. Perform TEST VER-1.
  3. Remove ASD relay. Substitute another relay. If substitute relay clicks, replace original ASD relay. Perform TEST VER-1. If substitute relay does not click, remove substitute relay. Using scan tool in voltmeter mode, check voltage on ASD relay connector 12-volt ignition feed circuit (Light Green/Black wire). If voltage is 10 volts or less, repair open Light Green/Black wire. Perform TEST VER-1.
  4. If voltage is more than 10 volts, turn ignition off. Using an external ohmmeter, check resistance across A/C clutch relay terminals. See Figure . If resistance is more than 100 ohms, replace ASD relay. Perform TEST VER-1.
  5. If resistance is less than 100 ohms, turn ignition off. Disconnect Powertrain Control Module (PCM). Using scan tool in ohmmeter mode, check resistance of PCM connector terminal No. 57, control circuit (Dark Green/Orange wire). If resistance is less than 5 ohms, repair short to ground in Dark Green/Orange wire. Perform TEST VER-1.
  6. If resistance is 5 ohms or more, use an external ohmmeter to check resistance of ASD relay connector control circuit (Dark Green/Orange wire) between PCM connector terminal No. 57 and ASD relay connector. If resistance is 5 ohms or more, repair open Dark Green/Orange wire. Perform TEST VER-1. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-1.
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