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Home >> Mitsubishi Truck >> 2001 >> Montero Sport LTD 4WD V6-3.5L SOHC >> Repair and Diagnosis >> Powertrain Management >> Transmission Control Systems >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Symptom Diagnosis Charts >> Inspection Procedure 18

Inspection Procedure 18






INSPECTION PROCEDURE 19: 4L Detection Switch System

CIRCUIT OPERATION
- A battery positive voltage is applied to the 4L detection switch output terminal (terminal 1) from the PCM (terminal 112) via the resistance in the unit.
- The 4L detection switch is grounded through the transfer case to the vehicle body.

COMMENT
- If the transmission will not shift to 3rd gear, or if it shifts to 3rd gear when the transfer lever is in the "41-m position, the cause is probably a malfunction of the 4L detection switch.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set:)
- Malfunction of the 4L detection 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 75: 4L Detection 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 "ON" position.
3. Set scan tool MB991502 to data reading mode for item 75:
4L Detection Switch.
- When the transfer shift lever position is 4L, the scan tool display should be "ON."
- When the transfer shift lever position is other than 4L, the scan tool display should be "OFF"
4. Turn the ignition switch to "LOCK"(OFF) position.
Q: Is the switch operating properly?
YES: This malfunction is intermittent. Refer to How to Use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction.
NO: Go to Step 2.





STEP 2. Check connector B-17 at 4L detection switch for damage.
Q: Is the connector In good condition?
YES: Go to Step 3.
NO: Repair or replace it.

STEP 3. Check the switch output voltage at 4L detection switch connector B-17.





1. Disconnect connector B-17 and measure at the harness side.
2. Turn the ignition switch to "ON" position.





3. Measure the voltage between terminal 1 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to "LOCK"(OFF) position.
Q: Is the voltage normal?
YES: Go to Step 9.
NO: Go to Step 4.

STEP 4. Check the switch output voltage at PCM connector C-92 by backprobing.





1. Do not disconnect connector C-92.
2. Turn the ignition switch to "ON" position.





3. Measure the voltage between terminal 112 and ground by backprobing.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to "LOCK"(OFF) position.
Q: Is the voltage normal?
YES: Go to Step 5.
NO: Go to Step 6.








STEP 5. Check connectors C-96 at intermediate connector and C-92 at PCM for damage.
Q: Are the connectors in good condition?
YES: Repair it because of harness open circuit between 4L detection switch connector B-17 terminal 1 and PCM connector C-92 terminal 112.
NO: Repair or replace it.








STEP 6. Check connectors C-96 at intermediate connector and C-92 at PCM for damage.
Q: Are the connectors in good condition?
YES: Go to Step 7.
NO: Repair or replace it.








STEP 7. Check harness for damage between 4L detection switch connector B-17 terminal 1 and PCM connector C-92 terminal 112.
Q: Is the harness wire in good condition?
YES: Go to Step 8.
NO: Repair it.





STEP 8. Using scan tool MB991502, check data list item 75: 4L Detection 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 "ON" position.
3. Set scan tool MB991502 to data reading mode for item 75:
Detection Switch.
- When the transfer shift lever position is 4L, the scan tool display should be "ON."
- When the transfer shift lever position is other than 4L, the scan tool display should be "OFF"
4. Turn the ignition switch to "LOCK"(OFF) position.
Q: Is the switch operating properly?
YES: This malfunction is intermittent. Refer to How to Use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction.
NO: Replace the PCM.

STEP 9. Check the continuity at 4L detection switch connector B-17.





1. Disconnect connector B-17 and measure at the switch side.
2. Turn the ignition switch to "ON" position.
3. Selector lever position should be "N" range.





4. Check for the continuity between terminal 1 and ground.
- When the transfer shift lever position is 4L there should be less than 2 ohm.
- When the transfer shift lever position is other than 4L there should be open circuit.
5. Turn the ignition switch to "LOCK"(OFF) position.
Q: Is the continuity normal?
YES: Go to Step 10.
NO: Replace the 4L detection switch.





STEP 10. Check connector C-92 at PCM for damage.
Q: Is the connector in good condition?
YES: Go to Step 11.
NO: Repair or replace ft.





STEP 11. Using scan tool MB991502, check data list item 75: 4L Detection 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 "ON" position.
3. Set scan tool MB991502 to data reading mode for Rem 75:
Detection Switch.
- When the transfer shift lever position is 4L, the scan tool display should be "ON".
- When the transfer shift lever position is other than 4L, the scan tool display should be "OFF"
4. Turn the ignition switch to "LOCK"(OFF) position.
Q: Is the switch operating properly?
YES: This malfunction is intermittent. Refer to How to Use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction.
NO: Replace the PCM.

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