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Home >> Mitsubishi Truck >> 2000 >> Montero Sport LS 2WD V6-3.0L SOHC >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> Transmission Control System >> DTC 54

DTC 54









CIRCUIT OPERATION
- A/T control relay (terminal number 1) receives the system voltage from the fusible link.
- When turning the ignition switch to "ON," the PCM receives system voltage from the ignition switch (terminal 98). Then the PCM (terminal number 50) applies a voltage to the A/T control relay (terminal number 4), and the A/T control relay switch is turned on. When the A/T control relay switch is turned on, the battery applies a power supply voltage to the PCM (terminal numbers 77 and 89).

DTC SET CONDITIONS
- If the A/T control relay voltage is less than 7 volts after the ignition switch has been turned to "ON," it is judged that there is an open circuit or a short-circuit in the A/T control relay ground and diagnostic trouble code number "54" is output. The transmission is locked into the 3rd gear as a fail-safe measure, and the "N" range light flashes at a frequency of 1 Hz.

TROUBLESHOOTING HINTS
The most likely causes for this code to be set:
- Malfunction of the A/T control relay
- Damaged connector
- Malfunction of the PCM

DIAGNOSIS





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

CAUTION: To prevent damage to scan tool MB991502, make sure the ignition switch is "OFF" before connecting or disconnecting the scan tool MB991502.

STEP 1. Using scan tool MB991502, check data list item 54: A/T control relay output voltage.
1. When the ignition switch is turned to "ON," scan tool shows system voltage.
2. When the ignition switch is turned to "OFF," the scan tool shows 0 volts.
If the A/T control relay is operating properly, it can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/inspection Service Points.
If the A/T control relay is not operating properly, check for 12 volts at terminal 98 when the ignition switch is turned ON. If not OK, check connectors, wiring, etc. between PCM and ignition switch. If OK, go to Step 2.

STEP 2. Check the A/T control relay.





1. Remove the A/T control relay.
2. Use jumper wires to connect terminal number 2 of the A/T control relay to the negative battery terminal, and terminal number 4 of the A/T control relay to the positive battery terminal.





3. Check continuity between terminal numbers 1 and 3 of the A/T control relay when the jumper wires are connected to the battery and disconnected from the battery.
If the check above meets the specification, go to Step 3.
If the check above does not meet the specification, replace the A/T control relay. Then confirm that the malfunction is eliminated.

STEP 3. Check connector C-97 at the A/T control relay for damage.





If harness connector C-97 is damaged, repair or replace it. Refer to Harness Connector Inspection. Recheck for DTCs.
If harness connector C-97 is in good condition, go to Step 4.

STEP 4. Check the harness wire between fusible link and A/T control relay connector C-97.





NOTE: After inspecting intermediate connectors D-02 and D-09, inspect the wire. If intermediate connectors D-02 and D-09 are damaged, repair or replace them. Refer to Harness Connector Inspection.

If any harness wire between battery and A/T control relay connector C-97 is damaged, repair it. Refer to Harness Connector Inspection. Recheck for DTCs.
If the harness wire is in good condition, go to Step 5.

STEP 5. Check the harness wire between A/T control relay connector C-97 and ground.





If any harness wire between A/T control relay connector C-97 and ground is damaged, repair it. Refer to Harness Connector Inspection. Recheck for DTCs.
If the harness wire is in good condition, go to Step 6.

STEP 6. Check harness connectors C-90 and C-91 at the PCM for damage.





If harness connectors C-90 and C-91 are damaged, repair or replace them. Refer to Harness Connector Inspection. Recheck for DTCs.
If harness connectors C-90 and C-91 are in good condition, go to Step 7.

STEP 7. Check the harness wire between PCM connectors C-90 and C-91 and A/T control relay connector C-97.





If any harness wires between PCM connectors C-90 and C-91 and A/T control relay connector C-97 are damaged, repair them. Refer to Harness Connector Inspection. Recheck for DTCs.
If the harness wires are in good condition, recheck for DTCs. If the malfunction is not eliminated, replace the PCM.


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