LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 2002 >> Wrangler X, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1899: P/N Switch Performance >> Testing
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P1899: P/N Switch Performance: Testing

  1. Turn the ignition on. With the DRBIII®, read PCM DTCs. Is the Good Trip counter displayed and equal to zero? If yes, go to next step. If no, go to step  7.
  2. Turn the ignition on. With the DRBIII®, read the Park/Neutral Position Switch input state. While moving the gear selector through all gear positions (Park to 1 and back to Park), monitor the DRB display. Did the DRB display show P/N and D/R in the correct gear positions? If yes, test is complete. If no, go next step.
  3. Turn the ignition off. Disconnect the PCM harness connectors. Disconnect the P/N Position Switch harness connector. Measure the resistance of the P/N Position Switch Sense circuit between the P/N Position Switch harness connector and PCM harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the P/N Position Switch Sense circuit for an open.
  4. Measure the resistance between ground and the P/N Position Switch Sense circuit at the P/N Position Switch harness connector. Is the resistance below 5.0 ohms? If yes, repair the P/N Position Switch Sense circuit for a short to ground. If no, go to next step.
  5. Turn the ignition off. Reconnect Transmission Range Sensor harness connector. Move the Gear selector through all gear positions, from Park to 1st and back. While moving the gear selector through each gear, measure the resistance between ground and the P/N Position Switch Sense circuit at PCM harness connector. Did the resistance change from below 10.0 ohms to above 10.0 ohms? If yes, go to next step. If no, replace the P/N Position Switch.
  6. There are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .
  7. At this time, the conditions required to set the DTC are not present. Use the Freeze Frame Data to help you duplicate the conditions that set the DTC. Pay particular attention to the DTC set conditions, such as VSS, MAP, ECT, and Load. 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. Refer to any Technical Service Bulletins (TSB) that may apply. Were any problems found? If yes, repair as necessary. If no, test is complete.
scientia non olet · About LEMON Manuals