P0816

DTC P0816: Short in Transmission Gear Selection Switch Downshift Switch Circuit, or Transmission Gear Selection Switch Downshift Switch Stuck ON

NOTE:
^ Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information.
^ This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.

1. Turn the ignition switch ON (II).
2. Leave the shift lever in the P position.
3. Check the DOWNSHIFT SWITCH in the DATA LIST with the HDS.
Is DOWNSHIFT SWITCH ON?
YES - Go to step 4.
NO - Intermittent failure, the system is OK at this time. Check for intermittent short to body ground in the wire between the transmission gear selection switch and the PCM.

4. Turn the ignition switch OFF.
5. Disconnect the transmission gear selection switch/park pin switch/A/T gear position indicator panel light connector.
6. Turn the ignition switch ON (II).
7. Check the DOWNSHIFT SWITCH in the DATA LIST with the HDS.
Is DOWNSHIFT SWITCH ON?
YES - Go to step 8.
NO - Replace the transmission gear selection switch, then go to step 12.

8. Turn the ignition switch OFF.
9. Jump the SCS line with the HDS.
10. Disconnect PCM connector E (31P).
11. Check for continuity between transmission gear selection switch/park pin switch/A/T gear position indicator panel light connector terminal No. 8 and body ground.





Is there continuity?
YES - Repair short in the wire between PCM connector terminal E13 and the transmission gear selection switch, then go to step 12.
NO - Go to step 20.

12. Reconnect all connectors.
13. Turn the ignition switch ON (II).
14. Clear the DTC with the HDS.
15. Start the engine in the P position, wait for more than 10 seconds, then press the brake pedal and shift to the M position.
16. Push the shift lever toward upshift position (+) slowly, and return to neutral position; repeat this test 10 times or more.
17. Pull the shift lever toward downshift position slowly, and return to neutral position; repeat this test 10 times or more.
18. Check for DTCs with the HDS.
Is DTC P0816 indicated?
YES - Check for intermittent short to body ground in the wire between the transmission gear selection switch and the PCM, then go to step 1.
NO - Go to step 19.

19. Monitor the OBD STATUS for P0816 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other DTCs were indicated in step 18, go to the indicated DTC's troubleshooting.
NO - If the screen indicates FAILED, check for intermittent short to body ground in the wire between the transmission gear selection switch and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 15.

20. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
21. Start the engine in the P position, wait for more than 10 seconds, then press the brake pedal and shift to the M position.
22. Push the shift lever toward upshift position (+) slowly, and return to neutral position; repeat this test 10 times or more.
23. Pull the shift lever toward downshift position slowly, and return to neutral position; repeat this test 10 times or more.
24. Check for DTCs with the HDS.
Is DTC P0816 indicated?
YES - Check for intermittent short to body ground in the wire between the transmission gear selection switch and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 21. If the PCM was substituted, go to step 1.
NO - Go to step 25.

25. Monitor the OBD STATUS for P0816 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other DTCs were indicated in step 24, go to the indicated DTC's troubleshooting.
NO - If the screen indicates FAILED, check for intermittent short to body ground in the wire between the transmission gear selection switch and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 21. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, go to step 21.