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Home >> Dodge and Ram >> 2003 >> Durango Base, 5.9 Z, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 15 (Engine Controls - Self Diagnostics - 4.7L) >> Diagnostic Tests >> DTC P0688: ASD Relay Sense Circuit Low >> Testing

DTC P0688: ASD Relay Sense Circuit Low: Testing

WARNING: This page is about a different car, the 2003 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: If DTC P0685 set along with DTC P0688, diagnose DTC P0685: ASD RELAY CONTROL CIRCUIT  first.
  1. With the DRBIII® scan tool, erase the DTC. Attempt to start the engine. If the engine will not start, crank the engine for at least 15 seconds. It may be necessary to repeat several times. Does the DTC reset. If yes, go to next step. If no, see INTERMITTENT CONDITION  under SELF-DIAGNOSTIC SYSTEM.
  2. Attempt to start the engine. Does the engine start. If yes, go to next step. If no, go to step  4.
    3. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool (8815) to perform diagnosis.
  3. Turn the ignition off. Remove the ASD relay from the PDC. Disconnect the PCM harness connectors. Measure the resistance of the (A142) ASD relay output circuit from the PDC to the appropriate terminal of the Miller Special Tool (8815). Is the resistance below 5.0 ohms? If yes, go to step  8. If no, repair the open in the (A142) ASD relay control circuit.
  4. Turn the ignition off. Install a substitute relay in place of the ASD relay. Ignition on, engine not running. With the DRBIII® scan tool, erase DTCs. Attempt to start the engine. With the DRBIII® scan tool, read DTCs. Does the DTC reset? If yes, go to next step. If no, replace the ASD relay.
  5. Turn the ignition off. Remove the ASD relay from the PDC. Using a 12-volt test light connect to ground, probe the (A16) fused B+ circuits in the PDC. Does the test light illuminate brightly? If yes, go to next step. If no, repair the open or short to ground in the (A16) fused B+ circuits. Inspect the related fuse and repair as necessary.
    6. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool (8815) to perform diagnosis.
  6. Disconnect the PCM harness connectors. Measure the resistance of the (A142) ASD relay output circuit from the PDC to the appropriate terminals of Miller Special Tool (8815). Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the open in the (A142) ASD relay output circuit.
  7. Measure the resistance between ground and the (A142) ASD relay output circuit at the relay connection. Is the resistance below 100 ohms? If yes, repair the short to ground in the (A142) ASD relay output circuit. If no, go to next step.
    8. NOTE: Before continuing, disconnect the PCM harness connectors and check the related wiring terminals for corrosion, damage or terminal push out. Repair as necessary.
  8. Using the wiring diagram as a guide, inspect the wire harness and connectors. Visually inspect the related wire harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect both the component and the PCM connectors. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, replace and program the PCM. See PROGRAMMING .
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