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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 P1596: Speed Control Switch Always High >> Testing:
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DTC P1596: Speed Control Switch Always High: 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. Start the engine. Using DRBIII® in SENSORS mode, read S/C input state. While monitoring display, press S/C ON/OFF switch in right S/C switch several times, then leave on. Does DRBIII® display S/C state switching OFF and ON? If yes, go to next step. If no, go to step  3.
    2. 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.
  2. 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.

  3. Turn ignition off. Disconnect S/C ON/OFF switch harness connector only from the right S/C switch. Measure resistance across S/C ON/OFF switch (component side). Is resistance 20,300-20,700 ohms? If yes, go to next step. If no, replace the right S/C switch. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS.
  4. Reconnect the S/C ON/OFF switch harness connector. Disconnect clockspring upper and lower harness connectors. Measure resistance of the sensor ground circuit between clockspring C1 (upper) harness connector terminal No. 4 and clockspring C3 (lower) harness connector terminal No. 3. Measure resistance of the speed control switch signal circuit between clockspring C1 harness connector terminal No. 5 and clockspring C3 harness connector terminal No. 2. Is resistance more than 5 ohms for either circuit? If yes, replace clockspring. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS. If no, go to next step.
  5. Reconnect clockspring harness connectors. Disconnect S/C ON/OFF switch harness connector only from the right S/C switch. Turn ignition on. Measure voltage of S/C switch signal circuit at right S/C switch harness connector terminal No. 1. Is voltage more than 5.2 volts? If yes, repair S/C switch signal circuit for a short to battery voltage. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS. If no, go to next step.
  6. Turn ignition off. Reconnect S/C ON/OFF switch harness connector. Disconnect clockspring C1 harness connector (instrument panel harness side). Disconnect PCM C3 harness connector. Measure resistance of S/C switch signal circuit between clockspring C1 harness connector terminal No. 5 and PCM C3 harness connector terminal No. 32. Is resistance less than 5 ohms? If yes, go to next step. If no, repair open in S/C switch signal circuit. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS.
  7. Reconnect PCM C3 harness connector. Disconnect S/C ON/OFF switch harness connector only from the right S/C switch. Measure resistance of S/C switch signal circuit between clockspring C1 harness connector terminal No. 5 and right S/C switch harness connector terminal No. 1. Is resistance less than 5 ohms? If yes, go to next step. If no, repair open in S/C switch signal circuit. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS.
  8. Measure resistance of sensor ground circuit between clockspring C1 harness connector terminal No. 4 and right S/C switch harness connector terminal No. 2. Is resistance less than 5 ohms? If yes, go to next step. If no, repair open in sensor ground circuit. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS.
  9. Reconnect S/C ON/OFF switch harness connector. Disconnect PCM C1 harness connector. Measure resistance of sensor ground circuit between clockspring C1 harness connector terminal No. 4 and PCM C1 harness connector terminal No. 4. Is resistance less than 5 ohms? If yes, go to next step. If no, repair open in sensor ground circuit. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS.
  10. If there are no possible causes remaining, replace PCM. Perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS.
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