DTC 27

DTC 27: Park/Neutral Position Switch System (Open Circuit)









CIRCUIT OPERATION
^ Battery positive voltage is applied to the Park/Neutral position switch (terminal 8) when the ignition switch is turned "ON."
^ Battery positive voltage is applied to the PCM (terminal 101) when the selector lever is in the lip l range. The PCM judges that the selector lever is in the "P" range when the battery positive voltage is applied.
^ Battery positive voltage is applied to the PCM terminal 108 (121, 102, 109, 122 or 110) when the selector lever is in the "R" range ("N," "D," "3," "2" or "L" range). The PCM judges that the selector lever is in the "R" range ("N" "D," "3," "2" or "L" range) when the battery positive voltage is applied.

DTC SET CONDITIONS If the PCM detects no Park/Neutral position switch input signal from any selector position for continuous period of thirty seconds, it is judged that there is an open circuit in the Park/Neutral position switch and diagnostic trouble code number "27" is set.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set:)
^ Malfunction of the Park/Neutral position switch
^ Malfunction of the ignition switch
^ Damaged harness, connector
^ Malfunction of the PCM

DIAGNOSIS

Required Special Tool: MB991502: Scan Tool (MUT-II)





STEP 1. Using scan tool MB991502, check data list item 61: Park/Neutral Position Switch.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991502 to data reading mode for item 61: Park/Neutral Position Switch.
^ Move the selector lever to "P," "R," "N," "D," "3," "27" "L," positions to confirm whether shown on the scan tool.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch operating properly?
YES: This malfunction is intermittent.
NO: When indication disagrees at all positions: Go to Step 2. When indication disagrees at "P" position: Go to Step 2. When indication disagrees at "R" position: Go to Step 11. When indication disagrees at "N" position: Go to Step 15. When indication disagrees at "D" position: Go to Step 19. When indication disagrees at "3" position: Go to Step 23. When indication disagrees at "2" position: Go to Step 27. When indication disagrees at "L" position: Go to Step 31.











STEP 2. Check for continuity between terminals for each selector position.
Q: Is the switch operating properly?
YES: Go to Step 3.
NO: Replace the Park/Neutral position switch.











STEP 3. Check connectors B-16 at Park/Neutral position switch, C-123 at intermediate connector and C-210 at junction block for damage.
Q: Are the connectors in good condition?
YES: Go to Step 4.
NO: Repair or replace the defective connectors.








STEP 4. Check harness for open circuit or short circuit to ground between Park/Neutral position switch connector B16 terminal 8 and junction block connector C-210 terminal 12.
Q: Is the harness wire in good condition?
YES: Go to Step 5.
NO: Repair it.





STEP 5. Using scan tool MB991502, check data list item 61: Park/Neutral Position Switch.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991502 to data reading mode for item 61: Park/Neutral Position Switch.
^ Move the selector lever to "P," "R," "N," "D," "3," "2," "L" positions to confirm whether shown on the scan tool.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch operating properly?
YES: This malfunction is intermittent.
NO: Replace the PCM.











STEP 6. Check for continuity between terminals for each selector position.
Q: Is the switch operating properly?
YES: Go to Step 7.
NO: Replace the Park/Neutral position switch.





STEP 7. Check connector B-16 at the Park/Neutral position switch for damage.
Q: Is the connector in good condition?
YES: Go to Step 8.
NO: Repair or replace it.

STEP 8. Check the switch output voltage at PCM connector C-114 by backprobing.





1. Do not disconnect connector C-114.
2. Turn the ignition switch to the "ON" position.
3. Move the selector lever to "P" position.





4. Measure the voltage between terminal 101 and ground by backprobing.
^ Voltage should be batted positive voltage.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 10.
NO: Go to Step 9.





STEP 9. Check connector C-114 at PCM for damage.
Q: Is the connector in good condition?
YES: Repair harness open circuit or short circuit to ground between Park/Neutral position switch connector B-16 terminal 3 and PCM connector C-114 terminal 101.
NO: Repair or replace it.





STEP 10. Check connector C-114 at PCM for damage.
Q: Is the connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it.











STEP 11. Check the Park/Neutral position switch. Check for continuity between terminals for each selector position.
Q: Is the switch operating properly?
YES: Go to Step 12.
NO: Replace the Park/Neutral position switch.





STEP 12. Check connector B-16 at the Park/Neutral position switch for damage.
Q: Is the connector in good condition?
YES: Go to Step 13.
NO: Repair or replace it.

STEP 13. Check the switch output voltage at PCM connector C-114 by backprobing.





1. Do not disconnect connector C-114.
3. Turn the ignition switch to the "ON" position.
3. Move the selector lever to "R" position.





4. Measure the voltage between terminal 108 and ground by backprobing.
^ Voltage should be battery positive voltage.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 10.
NO: Go to Step 14.





STEP 14. Check connector C-114 at PCM for damage.
Q: Is the connector in good condition?
YES: Repair harness open circuit or short circuit to ground between Park/Neutral position switch connector B-16 terminal 7 and PCM connector C-114 terminal 108.
NO: Repair or replace it.











STEP 15. Check the Park/Neutral position switch. Check for continuity between terminals for each selector position.
Q: Is the switch operating properly?
YES: Go to Step 16.
NO: Replace the Park/Neutral position switch.





STEP 16. Check connector B-16 at the Park/Neutral position switch for damage.
Q: Is the connector in good condition?
YES: Go to Step 17.
NO: Repair or replace it.

STEP 17. Check the switch output voltage at PCM connector C-114 by backprobing.





1. Do not disconnect connector C-114.
2. Turn the ignition switch to the "ON" position.
3. Move the selector lever to "N" position.





4. Measure the voltage between terminal 121 and ground by backprobing.
^ Voltage should be battery positive voltage.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 10.
NO: Go to Step 18.





STEP 18. Check connector C-114 at PCM for damage.
Q: Is the connector in good condition?
YES: Repair harness open circuit or short circuit to ground between the Park/Neutral position switch connector B-16 terminal 4 and PCM connector C-114 terminal 121.
NO: Repair or replace it.











STEP 19. Check the Park/Neutral position switch. Check for continuity between terminals for each selector position.
Q: Is the switch operating properly?
YES: Go to Step 20.
NO: Replace the Park/Neutral position switch.





STEP 20. Check connector B-16 at the Park/Neutral position switch for damage.
Q: Is the connector in good condition?
YES: Go to Step 21.
NO: Repair or replace it.

STEP 21. Check the switch output voltage at PCM connector C-114 by backprobing.





1. Do not disconnect connector C-114.
2. Turn the ignition switch to the "ON" position.
3. Move the selector lever to "D" position.





4. Measure the voltage between terminal 102 and ground by backprobing.
^ Voltage should be battery positive voltage.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 10.
NO: Go to Step 22.





STEP 22. Check connector C-114 at PCM for damage.
Q: Is the connector in good condition?
YES: Repair harness open circuit or short circuit to ground between the Park/Neutral position switch connector B-16 terminal 1 and PCM connector C-114 terminal 102.
NO: Repair or replace it.











STEP 23. Check the Park/Neutral position switch. Check for continuity between terminals for each selector position.
Q: Is the switch operating properly?
YES: Go to Step 24.
NO: Replace the Park/Neutral position switch.





STEP 24. Check connector B-16 at the Park/Neutral position switch for damage.
Q: Is the connector in good condition?
YES: Go to Step 25.
NO: Repair or replace it.

STEP 25. Check the switch output voltage at PCM connector C-114 by backprobing.





1. Do not disconnect connector C-114.
2. Turn the ignition switch to the "ON" position.
3. Move the selector lever to "3" position.





4. Measure the voltage between terminal 109 and ground by backprobing.
^ Voltage should be battery positive voltage.
5. Turn the ignition switch to "LOCK"(OFF) position.
Q: Is the voltage normal?
YES: Go to Step 10.
NO: Go to Step 26.





STEP 26. Check connector C-114 at PCM for damage.
Q: Is the connector in good condition?
YES: Repair harness open circuit or short circuit to ground between the Park/Neutral position switch connector B-16 terminal 5 and PCM connector C-114 terminal 109.
NO: Repair or replace it.











STEP 27. Check the Park/Neutral position switch. Check for continuity between terminals for each selector position.
Q: Is the switch operating properly?
YES: Go to Step 28.
NO: Replace the Park/Neutral position switch.





STEP 28. Check connector B-16 at the Park/Neutral position switch for damage.
Q: Is the connector in good condition?
YES: Go to Step 29.
NO: Repair or replace it.

STEP 29. Check the switch output voltage at PCM connector C-114 by backprobing.





1. Do not disconnect connector C-114.
2. Turn the ignition switch to the "ON" position.
3. Move the selector lever to "2" position.





4. Measure the voltage between terminal 122 and ground by backprobing.
^ Voltage should be battery positive voltage.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 10.
NO: Go to Step 30.





STEP 30. Check connector C-114 at PCM for damage.
Q: Is the connector in good condition?
YES: Repair harness open circuit or short circuit to ground between the Park/Neutral position switch connector B-16 terminal 2 and PCM connector C-114 terminal 122.
NO: Repair or replace it.











STEP 31. Check the Park/Neutral position switch. Check for continuity between terminals for each selector position.
Q: Is the switch operating properly?
YES: Go to Step 32.
NO: Replace the Park/Neutral position switch.





STEP 32. Check connector B-16 at the Park/Neutral position switch for damage.
Q: Is the connector in good condition?
YES: Go to Step 33.
NO: Repair or replace it.

STEP 33. Check the switch output voltage at PCM connector C-114 by backprobing.





1. Do not disconnect connector C-114.
2. Turn the ignition switch to the "ON" position.
3. Move the selector lever to "L" position.





4. Measure the voltage between terminal 110 and ground by backprobing.
^ Voltage should be battery positive voltage.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 10.
NO: Go to Step 34.





STEP 34. Check connector C-114 at PCM for damage.
Q: Is the connector in good condition?
YES: Repair harness open circuit or short circuit to ground between the Park/Neutral position switch connector B-16 terminal 6 and PCM connector C-114 terminal 110.
NO: Repair or replace it.