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Home >> Dodge and Ram >> 2003 >> Durango Base, 5.9 Z, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 5.9L >> Diagnostic Tests >> DTC P1597: Speed Control Switch Always Low >> Testing:
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DTC P1597: Speed Control Switch Always Low: Testing:

NOTE: Ensure vehicle being tested has a fully charged battery. If battery is not fully charged, false DTCs or error messages may occur.
NOTE: For component locations, see COMPONENT LOCATIONS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS .
  1. Turn ignition off. Connect DRBIII® to DLC. Turn ignition on. Using DRBIII®, read S/C switch volt state. Does DRBIII® display less than one volt? If yes, go to next step. If no, go to step  8
  2. Turn ignition off. Disconnect S/C ON/OFF switch harness connector only from the right S/C switch. Turn ignition on. Using DRBIII® in SENSORS, read S/C switch voltage. Did voltage change to 5 volts? If yes, replace right S/C switch. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS. If no, go to next step.
  3. Turn ignition off. Reconnect S/C ON/OFF switch harness connector. Disconnect S/C RESUME/ACCEL switch harness connector from left S/C switch. Turn ignition on. Using DRBIII® in SENSORS, read S/C switch voltage. Did voltage change to more than 4 volts? If yes, replace left S/C switch. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS. If no, go to next step.
  4. Turn ignition off. Reconnect S/C RESUME/ACCEL switch harness connector. Disconnect clockspring connector (instrument panel harness side). Turn ignition on. Using DRBIII® in SENSORS, read S/C switch voltage. Did voltage change to 5 volts? If yes, replace clockspring. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS. If no, go to next step.
  5. Turn ignition off. Reconnect clockspring harness connector. Disconnect S/C ON/OFF switch harness connector only from the right S/C switch. Disconnect PCM C3 harness connector. Measure resistance between S/C switch signal circuit at right S/C switch harness connector terminal No. 1 and ground. Is resistance less than 100 ohms? If yes, repair S/C switch signal circuit for short to ground. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS. If no, go to next step.
  6. Measure resistance between S/C switch signal circuit at right S/C switch harness connector terminal No. 1 and S/C switch sensor ground circuit at right S/C switch harness connector terminal No. 2. Is resistance less than 5 ohms? If yes, repair S/C switch signal circuit for short to sensor ground circuit. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS. If no, go to next step.
  7. If there are no possible causes remaining, replace PCM. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS.
    8. 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.
  8. Conditions that set DTC are not present at this time. The following list 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. Attempt to duplicate condition that caused DTC to set.
    • Refer to any Technical Service Bulletin (TSB) that may apply.
    • Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
    • Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.

    Were any of the above conditions present? If yes, repair as necessary. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS. If no, test is complete.

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