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Inspection Procedure 31

CIRCUIT OPERATION
- If the selector lever is moved to "P" or "N" range and the ignition switch is turned to "START" position, battery positive voltage is supplied to PCM (terminal 58) through the ignition switch and park/neutral position switch. Because of this, the PCM detects that the engine is cranking.
- The park/neutral position switch detects the selector lever position (P, N or other ranges) and converts it to voltage signal (high or low). Then the park/neutral position switch send that signal to the PCM.
Battery positive voltage is applied from PCM (terminal 59) through the resistor inside the PCM to the park/neutral position switch (terminal 10)
If the selector lever is moved to "P" or "N" range with the ignition switch turned on (except "START" position), continuity will exist between the PCM and ground through the park/neutral position switch and starter motor. The terminal voltage of the PCM will become low. If the selector lever is moved to the other ranges, continuity will be lost between the PCM and ground. The terminal voltage of the PCM will become high.

TROUBLESHOOTING HINTS
The most likely caused for this code to be set are:
- Malfunction of the ignition switch.
- Malfunction of the park/neutral position switch.
- Improper connector contact, open circuit or short-circuit in the harness wire.
- Malfunction of the PCM.




WIRING DIAGRAM




CONNECTORS

DIAGNOSIS

STEP 1. Check the park/neutral position switch.
Refer to On-vehicle Service.
If the park/neutral position switch is not defective, go to Step 2.
If the park/neutral position switch is defective, replace the park/neutral position switch. Then check that the malfunction is eliminated.




STEP 2. Check the circuit at park/neutral position switch connector B-39.
1. Disconnect connector B-39 and measure at the harness side.
2. Turn the ignition switch "ON."
3. Measure the voltage between terminal 10 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).
4. Turn the ignition switch "OFF"
If not approximately 12 volts, go to Step 3. If approximately 12 volts, go to Step 5.







STEP 3. Check the harness wire between park/neutral position switch connector B-39 (terminal 10) and PCM connector C-40 (terminal 59).
If no harness wire between park/neutral position switch connector B-39 (terminal 10) and PCM connector C-40 (terminal 59) is damaged, go to Step 4.
If any harness wire between park/neutral position switch connector B-39 (terminal 10) and PCM connector C-40 (terminal 59) is damaged, repair it. Then check that the malfunction is eliminated.




STEP 4. Check harness connector C-40 at the PCM for damage.
If harness connector C-40 is damaged, repair or replace it.
Refer to Harness Connector Inspection >.
If harness connector C-40 is in good condition, replace the PCM.
Then check that the malfunction is eliminated.

STEP 5. Check the circuit at the park/neutral position switch connector B-39.
1. Disconnect connector B-39 and measure at the harness side.
2. Disconnect PCM connector C-40.
3. Turn the ignition switch "START."
4. Measure the voltage between terminal 9 and ground.
- Voltage should be approximately 12 volts (battery positive voltage)
5. Turn the ignition switch "OFF."
If approximately 12 volts, go to Step 6.
If not approximately 12 volts, check the harness wires between the park/neutral position switch and the ignition switch connector; and the starter relay circuit (vehicles with theft-alarm system). Then repair if necessary. Refer to Harness Connector Inspection >. Then check that the malfunction is eliminated.







STEP 6. Check the harness wire between the park/neutral position switch connector B-39 (terminal 9) and PCM connector C-40 (terminal 58).
If no harness wire between park/neutral position switch connector B-39 (terminal 9) and PCM connector C-40 (terminal 58) is damaged, go to Step 7.
If any harness wire between park/neutral position switch connector B-39 (terminal 9) and PCM connector C-40 (terminal 58) is damaged, repair it. Then check that the malfunction is eliminated.







STEP 7. Check the harness connector B-39 at the park/neutral position switch and the harness connector C-40 at the PCM for damage.
If harness connectors B-39 and C-40 are in good condition, replace the PCM.
If the harness connectors B-39 and C-40 are damaged, repair or replace them. Refer to Harness Connector Inspection >.
Then check the malfunction is eliminated.
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