DTC P1899: P/N PERFORMANCE

Monitor & Set Conditions

Park/Neutral (P/N) switch is monitored continuously with transmission in Park, Neutral or Drive and not in limp-in mode. DTC may be stored if PCM detects an incorrect P/N switch state for an given mode of operation.

Possible Causes

• Intermittent Transmission Range Switch (TRS) Sense Circuit
• TRS
• TRS Sense Circuit Open
• TRS Sense Circuit Shorted To Ground
• Powertrain Control Module (PCM)

Testing

1. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for DTCs. If Good Trip Counter for DTC P1899 is displayed and equal to zero, go to next step. If Good Trip Counter for DTC P1899 is displayed and not equal to zero, go to step 7 .

2. Ensure ignition is on with engine off. Using scan tool, read TRS INPUT STATE. Observe scan tool display while moving gear selector through all gear positions, ending in Park. If scan tool display matches all actual gear positions, test is complete. If scan tool display does not match all actual gear positions, go to next step.

3. Turn ignition off. Disconnect PCM harness connector C1. PCM is located at passenger's side rear corner of engine compartment. Disconnect TRS harness connector. TRS is located on side of transmission. Check for poor connection/terminal contact at PCM harness connector and at TRS harness connector. Repair as necessary. Using DVOM, measure resistance of Black/White wire between terminal No. 2 on TRS harness connector and terminal No. 6 on PCM harness connector C1. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open in Black/White wire between TRS and PCM.

4. Using DVOM, measure resistance between ground and terminal No. 6 (Black/White wire) on PCM harness connector C1. If resistance is less than 5 ohms, repair short to ground in Black/White wire between TRS and PCM. If resistance is 5 ohms or greater, go to next step.

5. Using DVOM, measure resistance between ground and terminal No. 6 (Black/White wire) on PCM harness connector C1 while moving gear selector through all gear positions, ending in Park. If resistance changed from greater than 10 ohms to less than 10 ohms, go to next step. If resistance did not change from greater than 10 ohms to less than 5 ohms, replace TRS.

6. Replace and program PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.

7. Conditions required to set DTC are not present at this time. Check that displayed DTC matches the FREEZE FRAME DTC. Try to duplicate conditions recorded in FREEZE FRAME data. Inspect wiring and connectors between TRS and PCM. TRS switch is located on side of transmission. Repair wiring or connectors as necessary.