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DTC P1388: Auto Shutdown Relay Control Circuit: Testing

  1. Turn ignition on, engine not running. With the DRBIII®, read DTCs. Is the DTC Specific Good Trip counter displayed and equal to zero? If yes, go to next step. If no, go to step  7.
  2. Turn the ignition off. Remove the ASD relay from the PDC. Turn ignition on, engine not running. Measure the voltage on the Fused Ignition Switch Output circuit at the ASD Relay connector in the PDC. Is the voltage above 10.0 volts? If yes, go to next step. If no, repair the Fused Ignition Output circuit for an open. Check all related fuses and replace as necessary.
  3. Turn the ignition off. Disconnect the PCM harness connectors. Measure the resistance between ground and the ASD Relay Control circuit at the PDC. Is the resistance below 100 ohms? If yes, repair the ASD Relay Control circuit for a short to ground. If no, go to next step.
  4. Measure the resistance between terminals No. 85 and 86 of the ASD Relay (component side). Is the resistance between 50 and 80 ohms? If yes, go to next step. If no, replace the ASD Relay.
  5. Measure the resistance of the ASD Relay Control circuit from the ASD Relay cavity in the PDC to the PCM harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the ASD Relay Control circuit for an open.
  6. There are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .
    7. WARNING: When the engine is operating, do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing.
  7. The conditions that set the DTC are not present at this time. The following may help in identifying the intermittent condition. With the engine running at normal operating temperature, monitor the DRBIII® parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set. Review the DRBIII® Freeze Frame information. If possible, try to duplicate the conditions under which the DTC was set. Refer to any Technical Service Bulletins (TSB) that may apply. Visually inspect the related wire harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals. Were any of the above conditions present? If yes, repair as necessary. If no, test is complete.
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