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Home >> Dodge and Ram >> 2001 >> Durango 5.9 Z, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1388: Auto Shutdown Relay Control Circuit >> Testing
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DTC P1388: Auto Shutdown Relay Control Circuit: Testing

  1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1388 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1388 is not displayed or displayed count is not "0", go to step  7.
  2. Turn ignition off. Remove ASD relay from Power Distribution Center (PDC). See Figure. PDC is located in engine compartment, next to battery. Disconnect PCM connectors. PCM is located in engine compartment on passenger-side inner fender panel. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. Using DVOM, measure resistance of ASD relay control circuit (Dark Blue/Yellow wire) between ASD relay cavity No. 85 and PCM harness connector C3 terminal No. 3. See Figure and Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Blue/Yellow wire between PDC and PCM.
  3. Turn ignition on. Measure voltage of fused battery (+) output circuit (Red/White wire) between ground and ASD relay cavity No. 86. See Figure. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Red/White wire between ASD relay and junction connector No. 1 terminal No. 24, located in PDC. Repair wiring as necessary. See WIRING DIAGRAMS article.
  4. Turn ignition off. Ensure PCM is disconnected and ASD relay is removed from PDC. Measure resistance between ground and PCM harness connector C3 terminal No. 3 (Dark Blue/Yellow wire). See Figure. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Blue/Yellow wire between ASD relay and PCM.
  5. Measure resistance between ASD relay terminals No. 85 and 86 (component side). See Figure. If resistance is 50-80 ohms, go to next step. If resistance is not 50-80 ohms, replace ASD relay.
  6. At this time, PCM is assumed to be defective. Replace PCM.
  7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, reconnect all connectors. Check for any related Technical Service Bulletins (TSBs) that may apply. Start engine. Wiggle wiring harness from ASD relay to PCM while monitoring scan tool display. PCM is located in engine compartment on passenger-side inner fender panel. If GOOD TRIP counter display changes to "0", repair connector or wiring harness where wiggling caused display to change. If GOOD TRIP counter display does not change to "0", no problem is indicated at this time.
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