FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Mitsubishi >> 2004 >> Eclipse V6-3.0L SOHC >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P1751

P1751

DTC 54 (P1751): A/T Control Relay System A/T Control Relay System Circuit

Part 1 Of 2:




Part 2 Of 2:






CIRCUIT OPERATION
^ A/T control relay (terminal 1) receives battery positive voltage through a dedicated 20 amp fuse.
^ The PCM (terminal 50) applies voltage to energize the A/T control relay (terminal 2). With the A/T control relay energized, system voltage is applied to the PCM (terminals 77 and 89).

DESCRIPTIONS OF MONITOR METHODS
If relay output voltage is below specified value, PCM judges that A/T control relay has a failure.

MONITOR EXECUTION
Continuous

MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored)
^ DTC 41 (P0731): 1st gear incorrect ratio
^ DTC 42 (P0732): 2nd gear incorrect ratio
^ DTC 43 (P0733): 3rd gear incorrect ratio
^ DTC 44 (P0734): 4th gear incorrect ratio
^ DTC 46 (P0736): Reverse gear incorrect ratio
^ DTC 36 (P0743): Torque converter clutch solenoid malfunction
^ DTC 31 (P0753): Low-reverse solenoid malfunction
^ DTC 32 (P0758): Underdrive solenoid malfunction
^ DTC 33 (P0763): Second solenoid malfunction
^ DTC 34 (P0768): Overdrive solenoid malfunction
Sensor (The sensor is determined to be normal)
^ Torque converter clutch solenoid
^ Low-reverse solenoid
^ Underdrive solenoid
^ Second solenoid
^ Overdrive solenoid





LOGIC FLOW CHARTS (Monitor Sequence)

DTC SET CONDITIONS
Check Conditions
^ Voltage of battery: 9 volts or more.
^ Time after PCM turns on A/T control relay: 0.5 second or more.

Judgement Criteria
^ A/T control relay output voltage: 7 volts or less. (0.1 second)
^ If DTC 54 (P1751) is set consecutively four times, the transaxle is locked into 3rd gear as a fail-safe measure, and the "N" range light flashes once per second.
OBD-II DRIVE CYCLE PATTERN Start the engine, and keep the vehicle stopped in "P" range for 5 seconds.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
^ Malfunction of the A/T control relay
^ Damaged harness or connector
^ Malfunction of the PCM

DIAGNOSIS

Required Special Tool:
^ MB991958: Scan Tool (MUT-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: MUT-III USB Cable
^ MB991911: MUT-III Main Harness B

STEP 1. Using scan tool MB991958, check data list item 54: A/T Control Relay Output Voltage.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.





1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Set scan tool MB991958 to data reading mode for item 54: A/T Control Relay Output Voltage.
^ The voltage should equal battery positive voltage.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage equal battery positive voltage?
YES: It can be assumed that this malfunction is intermittent.
NO: Go to Step 2.

STEP 2. Check the A/T control relay.





1) Remove the A/T control relay from the engine compartment relay box connector A-17X.





2) Using jumper wires, connect terminal 3 to the negative battery terminal, and terminal 2 to the positive battery terminal.
3) Measure the resistance between terminals 1 and 4 of the A/T control relay.
^ The resistance should measure less than 2 ohms.
^ Disconnect the jumper wires. The resistance between terminals 1 and 4 should measure over limits (open circuit).
Q: Is the resistance measure less than 2 ohms when the relay is energized, and open circuit when the relay is de-energized?
YES: Go to Step 3.
NO: Replace the A/T control relay.

STEP 3. Check A/T control relay socket A-17X in the engine compartment relay box for loose, corroded or damaged terminals, or terminals pushed back in the socket.





Q: Is the relay socket in good condition?
YES: Go to Step 4.
NO: Repair or replace the damaged components.

STEP 4. Measure the supply voltage at A/T control relay connector A-17X in the engine component relay box.





1) Disconnect the A/T control relay.





2) Measure the voltage between terminal 1 and ground.
^ The measured voltage should equal battery positive voltage.
Q: Is the measured voltage equal to battery positive voltage? YES: Go to Step 7.
NO: Go to Step 5.

STEP 5. Check intermediate connector C-07 for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q: Are the connector and terminals in good condition?
YES: Go to Step 6.
NO: Repair or replace the damaged components.

STEP 6. Check the harness for open circuit or short circuit to ground between A/T control relay connector A-17X terminal 1 in the engine component relay box and battery.





Q: Is the harness wire in good condition?
YES: Go to Step 17.
NO: Repair or replace the harness wire.

STEP 7. Measure the resistance at A/T control relay connector A-17X in the engine component relay box.





1) Disconnect the A/T control relay.





2) Measure the resistance between terminal 3 and ground.
^ The resistance should measure less than 2 ohms.
Q: Is the measured resistance less than 2 ohms?
YES: Go to Step 9.
NO: Go to Step8.

STEP 8. Check the harness for open circuit or damage between A/T control relay connector A-17X terminal 3 in the engine component relay box and ground.





Q: Is the harness wire in good condition?
YES: Go to Step 17.
NO: Repair or replace the harness wire.

STEP 9. Measure the control voltage to A/T control relay connector A-17X in the engine component relay box.





1) Disconnect the A/T control relay.
2) Turn the ignition switch to the "ON" position.





3) Measure the voltage between terminal 2 and ground.
^ The measured voltage should equal battery positive voltage.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage equal to battery positive voltage?
YES: Go to Step 14.
NO: Go to Step 10.

STEP 10. Check the supply voltage at PCM connector C-54 <2.4L Engine> or C-55 <3.0L Engine> by backprobing.





1) Do not disconnect connector C-54 <2.4L Engine> or C-55 <3.0L Engine>.
2) Turn the ignition switch to the "ON" position.





3) Measure the voltage between terminal 50 and ground by backprobing.
^ The measured voltage should equal battery positive voltage.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Does the measured voltage equal battery positive voltage?
YES: Go to Step 11.
NO: Go to Step 13.

STEP 11. Check PCM connector C-54 <2.4L Engine> or C-55 <3.0L Engine> for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q: Are the connector and terminals in good condition?
YES: Go to Step 12.
NO: Repair or replace the damaged components.

STEP 12. Check the harness for open circuit or damage between A/T control relay connector A-17X terminal 2 in the engine component relay box and PCM connector C-54 <2.4L Engine> or C-55 <3.0L Engine> terminal 50.








Q: Is the harness wire in good condition?
YES: Go to Step 17.
NO: Repair or replace the harness wire.

STEP 13. Check for a short circuit to ground between A/T control relay socket A-17X terminal 2 and PCM connector C-54 <2.4L Engine> or C-55 <3.0L Engine> terminal 50.








Q: Is the harness wire in good condition?
YES: Go to Step 17.
NO: Repair or replace the harness wire.

STEP 14. Check the A/T control relay output voltage at PCM connector C-57 <2.4L Engine> or C-59 <3.0L Engine> by backprobing.





1) Do not disconnect connector C-57 <2.4L Engine> or C-59 <3.0L Engine>.
2) Turn the ignition switch to the "ON" position.





3) Measure the voltage between terminal 77 and ground by backprobing.
^ The measured voltage should equal battery positive voltage.





4) Measure the voltage between terminal 89 and ground by backprobing.
^ The measured voltage should equal battery positive voltage.
5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage equal to battery positive voltage between terminal 77 and ground, and between terminal 89 and ground?
YES: Go to Step 17.
NO: Go to Step 15.

STEP 15. Check PCM connector C-57 <2.4L Engine> or C-59 <3.0L Engine> for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q: Are the connector and terminals in good condition?
YES: Go to Step 16.
NO: Repair or replace the damaged components.

STEP 16. Check the harness for open circuit or short circuit to ground between A/T control relay connector A-17X (terminal 3) in the engine component relay box and junction block connector C-57 <2.4L Engine> or C-59 <3.0L Engine> (terminals 77 and 89).








Q: Is the harness wire in good condition?
YES: Go to Step 17.
NO: Repair or replace the harness wire.

STEP 17. Using scan tool MB991958, check data list item 54: A/T Control Relay Output Voltage.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.





1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to "ON" position.
3) Set scan tool MB991958 to data reading mode for item 54: A/T Control Relay Output Voltage.
^ The voltage should equal battery positive voltage.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage equal to battery positive voltage?
YES: It can be assumed that this malfunction is intermittent.
NO: Replace the PCM.



pro multis Credits:Operation CHARM About Operation CHARM