DTC 28

DTC 28: Park/Neutral Position Switch System (Short 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 "P" 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 more than one kind of park/neutral position switch input signals for continuous period of thirty seconds, it is judged that there is a short circuit in the Park/Neutral position switch and diagnostic trouble code number "28" is output.

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. Check the Park/Neutral position switch. Check for continuity between terminals for each selector position.

NOTE: For vehicles with sport mode, four positions (P, R, N, D) are used.











Q: Is the switch operating properly?
YES: Go to Step 2.
NO: Replace the Park/Neutral position switch.

STEP 2. Check connector B 41 at the Park/Neutral position switch for damage.





Q: Is the connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it.

STEP 3. Check connector C-61 <2.4L Engine> or C-63 <3.0L Engine> at PCM for damage.





Q: la the connector in good condition?
YES: Go to Step 4.
NO: Repair or replace it.

STEP 4. Check the switch output voltage at PCM connector C-61 <2.4L Engine> or C-63 <3.0L ENGINE> by backprobing. ("P" position)





1. Do not disconnect connector C-61 <2.4L Engine> or C-63 <3.0L Engine>.





2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 101 and ground by backprobing.
^ When selector lever position is "P," voltage should be battery positive voltage.
^ When selector lever position is "R," voltage should be 0.5 volt or less.
^ When selector lever position is "N." voltage should be 0.5 volt or less.
^ When selector lever position is "D," voltage should be 0.5 volt or less.
^ When selector lever position is "3," voltage should be 0.5 volt or less.
^ When selector lever position is "2," voltage should be 0.5 volt or less.
^ When selector lever position is "L," voltage should be 0.5 volt or less.
^ When selector lever position is sport mode, voltage should be 0.5 volt or less.
Q: Is the voltage normal?
YES: Go to Step 7.
NO: Turn the ignition switch to the "LOCK" (OFF) position. Go to Step 5 . Repair harness damage between the Park/Neutral position switch connector B-41 terminal 3 and PCM connector C-61 terminal 101 Vehicles without sport mode>.

STEP 5. Check harness for damage between Park/Neutral position switch connector B-41 terminal 3 and PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> terminal 101.

Q: Is the harness wire in good condition?
YES: Go to Step 6.
NO: Repair it.

STEP 6. Check connectors C-27 at intermediate connector and C-43 at combination meter for damage.

Q: Are the connectors in good condition?
YES: Repair harness damage between the Park/Neutral position switch connector B-11 terminal 3 and combination meter connector C-43 terminal 11.
NO: Repair or replace the defective connector(s).

STEP 7. Check the switch output voltage at PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> by backprobing. ("R" position) Measure the voltage between terminal 108 and ground by backprobing.

^ When selector lever position is "P," voltage should be 0.5 volt or less.
^ When selector lever position is "R," voltage should be battery positive voltage.
^ When selector lever position is "N," voltage should be 0.5 volt or less.
^ When selector lever position is "D," voltage should be 0.5 volt or less.
^ When selector lever position is "3," voltage should be 0.5 volt or less.
^ When selector lever position is "2," voltage should be 0.5 volt or less. Vehicles without sport mode>
^ When selector lever position is "L," voltage should be 0.5 volt or less.
^ When selector lever position is sport mode, voltage should be 0.5 volt or less.
Q: Is the voltage normal?
YES: Go to Step 10.
NO: Turn the ignition switch to the "LOCK" (OFF) position. Go to Step 8 . Repair harness damage between the Park/Neutral position switch connector B-41 terminal 7 and PCM connector C-61 terminal 108 Vehicles without sport mode>.

STEP 8. Check harness for damage between Park/Neutral position switch connector B-41 terminal 7 and PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> terminal 108.

Q: Is the harness wire in good condition?
YES: Go to Step 9.
NO: Repair it.

STEP 9. Check connectors C-27 at intermediate connector and C-63 at combination meter for damage.

Q: Are the connectors in good condition?
YES: Repair harness damage between the Park/Neutral position switch connector B-41 terminal 7 and combination meter connector C-63 terminal 10.
NO: Repair or replace the defective connector(s).

STEP 10. Check the switch output voltage at PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> by backprobing. ("N" position) Measure the voltage between terminal 121 and ground by backprobing.

^ When selector lever position is "P," voltage should be 0.5 volt or less.
^ When selector lever position is "R," voltage should be 0.5 volt or less.
^ When selector lever position is "N," voltage should be battery positive voltage.
^ When selector lever position is "D," voltage should be 0.5 volt or less.
^ When selector lever position is "3," voltage should be 0.5 volt or less. Vehicles without sport mode>
^ When selector lever position is "2," voltage should be 0.5 volt or less.
^ When selector lever position is "L," voltage should be 0.5 volt or less.
^ When selector lever position is sport mode, voltage should be 0.5 volt or less. Q: Is the voltage normal?
YES: Go to Step 13.
NO: Turn the ignition switch to the "LOCK" (OFF) position. Go to Step 11 . Repair harness damage between the Park/Neutral position switch connector B-41 terminal 4 and PCM connector C-61 terminal 121 .

STEP 11. Check harness for damage between Park/Neutral position switch connector B-41 terminal 4 and PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> terminal 121.

Q: Is the harness wire in good condition?
YES: Go to Step 12.
NO: Repair it.

STEP 12. Check connectors C-27 at intermediate connector C-43 at combination meter for damage.

Q: Are the connectors in good condition?
YES: Repair harness damage between the Park/Neutral position switch connector B-41 terminal 4 and combination meter connector C-43 terminal 9.
NO: Repair or replace the defective connector(s).

STEP 13. Check the switch output voltage at PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> by backprobing. ("D" position) Measure the voltage between terminal 102 and ground by backprobing.

^ When selector lever position is "P," voltage should be 0.5 volt or less.
^ When selector lever position is "R," voltage should be 0.5 volt or less.
^ When selector lever position is "N," voltage should be 0.5 volt or less.
^ When selector lever position is "D," voltage should be battery positive voltage.
^ When selector lever position is "3," voltage should be 0.5 volt or less. ^ When selector lever position is "2," voltage should be 0.5 volt or less.
^ When selector lever position is "L," voltage should be 0.5 volt or less. ^ When selector lever position is sport mode, voltage should be 0.5 volt or less.
Q: Is the voltage normal?
YES: Go to Step 20 . Go to Step 17 .
NO: Tern the ignition switch to the "LOCK" (OFF) position. Go to Step 14 . Repair harness damage between the Park/Neutral position switch connector B-41 terminal 1 and PCM connector C-61 terminal 102 .

STEP 14. Check harness for damage between Park/Neutral position switch connector B-41 terminal 1 and PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> terminal 102.

Q: Is the harness wire in good condition?
YES: Go to Step 15.
NO: Repair it.

STEP 15. Check connectors C-65 at shift switch assembly, C-27 at intermediate connector and C-41 at combination meter for damage. Vehicles with sport mode>

Q: Are the connectors in good condition?
YES: Go to Step 16.
NO: Repair or replace the defective connector(s).

STEP 16. Check harness for damage between Park/Neutral position switch connector B-41 terminal 1 and shift switch assembly connector C-65 terminal 1.

Q: Is the harness wire in good condition?
YES: Repair harness damage between shift switch assembly connector C-65 terminal 2 and combination meter connector C-41 terminal 50.
NO: Repair it.

STEP 17. Check the switch output voltage at PCM connector C-61 by backprobing. ("3" position) Measure the voltage between terminal 109 and ground by backprobing.

^ When selector lever position is "P," voltage should be 0.5 volt or less.
^ When selector lever position is "R," voltage should be 0.5 volt or less.
^ When selector lever position is "N," voltage should be 0.5 volt or less.
^ When selector lever position is "D," voltage should be 0.5 volt or less.
^ When selector lever position is "3," voltage should be battery positive voltage.
^ When selector lever position is "2," voltage should be 0.5 volt or less.
^ When selector lever position is "L," voltage should be 0.5 volt or less.
Q: Is the voltage normal?
YES: Go to Step 18.
NO: Turn the ignition switch to the "LOCK" (OFF) position. Repair harness damage between the Park/Neutral position switch connector B-41 terminal 5 and PCM connector C-61 terminal 109.

STEP 18. Check the switch output voltage at PCM connector C-61 by backprobing. ("2" position) Measure the voltage between terminal 122 and ground by backprobing.

^ When selector lever position is "P," voltage should be 0.5 volt or less.
^ When selector lever position is "R," voltage should be 0.5 volt or less.
^ When selector lever position is "N," voltage should be 0.5 volt or less.
^ When selector lever position is "D," voltage should be 0.5 volt or less.
^ When selector lever position is "3," voltage should be 0.5 volt or less.
^ When selector lever position is "2," voltage should be battery positive voltage.
^ When selector lever position is "L," voltage should be 0.5 volt or less.
Q: Is the voltage normal?
YES: Go to Step 19.
NO: Tern the ignition switch to the "LOCK" (OFF) position. Repair harness damage between the Park/Neutral position switch connector B-41 terminal 2 and PCM connector C-61 <2.4L Engine> or C-63 <3.0L Engine> terminal 122.

STEP 19. Check the switch output voltage at PCM connector C-61 by backprobing. ("L" position) Measure the voltage between terminal 110 and ground by backprobing.

^ When selector lever position is "P," voltage should be 0.5 volt or less.
^ When selector lever position is "R," voltage should be 0.5 volt or less.
^ When selector lever position is "N," voltage should be 0.5 volt or less.
^ When selector lever position is "D," voltage should be 0.5 volt or less.
^ When selector lever position is "3," voltage should be 0.5 volt or less.
^ When selector lever position is "2," voltage should be 0.5 volt or less.
^ When selector lever position is "L," voltage should be battery positive voltage.
Q: la the voltage normal?
YES: Go to Step 20.
NO: Turn the ignition switch to the "LOCK" (OFF) position. Repair harness damage between the Park/Neutral position switch connector B-41 terminal 6 and PCM connector C-61 terminal 110.

STEP 20. 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 the "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" and sport mode positions and confirm the scan tool display. (Vehicles with sport mode is indicated as "D" on the scan tool.)
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch operating properly?
YES: This malfunction can be intermittent.
NO: Replace the PCM.