DTC 82

DTC 82: Electric Pump Relay System

ELECTRIC PUMP RELAY SYSTEM CIRCUIT
Refer to DTC 81. DTC 81

CIRCUIT OPERATION
Refer to DTC 81. DTC 81

DTC SET CONDITIONS
DTC 82 is set when the pressure sensor does not reach the specified value even if the AWD-ECU has output the electric pump motor drive command.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)
^ Insufficient fluid
^ Malfunction of the pressure sensor
^ Malfunction of the electric pump relay
^ Malfunction of the hydraulic unit
^ Damaged harness and connector
^ Malfunction of the AWD-ECU

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

STEP 1. Check the fluid.
Check that the right amount of fluid is in the reservoir tank.
Q: Is the check result normal?
YES: Go to Step 3.
NO: Go to Step 2.

STEP 2. Check the fluid leaks.
Check that the fluid is not leaking.
Q: Is the check result normal?
YES: Add the fluid.
NO: Repair the leaking part and add the fluid.

STEP 3. Using scan tool MB991958, read the ACD diagnostic trouble code.





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) Check for ACD diagnostic trouble code.
4) Turn the ignition switch to the LOCK (OFF) position.
Q: Are DTCs 45, 46, 47 set?
YES : Refer to DTC 45: Pressure Sensor System (Open Circuit or Short Circuit). DTC 45
YES : Refer to DTC 46: Pressure Sensor System (Open Ground). DTC 46
YES : Refer to DTC 47: Pressure Sensor System (Abnormal Power Supply). DTC 47
NO: Go to Step 4.

STEP 4. Using scan tool MB991958, read the ACD diagnostic trouble code.





1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the ON position.
3) Check for ACD diagnostic trouble code.
4) Turn the ignition switch to the LOCK (OFF) position.
Q: Is DTC 81 set?
YES: Refer to DTC 81: Electric Pump Relay System. DTC 81
NO: Go to Step 5.

STEP 5. Using scan tool MB991958, check actuator test item 04: Electric Pump Drive.





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 actuator test mode.
^ Item 04: Electric Pump Drive.
^ Operating sound of the electric pump can be heard.

4) Turn the ignition switch to the LOCK (OFF) position.
Q: Is the pump operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Go to Step 6.

STEP 6. Measure the voltage at electric pump relay connector B-122.








Disconnect the electric pump relay connector, and measure the voltage between terminal 4 and ground.
^ The voltage should measure battery positive voltage.
Q: Is the measured voltage battery positive voltage?
YES: Go to Step 10.
NO: Go to Step 7.

STEP 7. Check electric pump relay connector B-122 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 8.
NO: Repair or replace the damaged components.

STEP 8. Check the harness for open circuit short circuit to ground between the ignition switch and the electric pump relay connector B-122 terminal 4 and fusible link 27.





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

STEP 9. Using scan tool MB991958, check actuator test item 04: Electric Pump Drive.





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 actuator test mode.
^ Item 04: Electric Pump Drive.
^ Operating sound of the electric pump can be heard.

4) Turn the ignition switch to the LOCK (OFF) position.
Q: Is the pump operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Replace the AWD-ECU.

STEP 10. Check electric pump connector B-29 and electric pump relay connector B-122 for loose, corroded or damaged terminals, or terminals pushed back in the connector.








Q: Are the connectors and terminals in good condition?
YES: Go to Step 11.
NO: Repair or replace the damaged components.

STEP 11. Check the harness for open circuit between electric pump relay connector B-122 terminal 3 and ground.





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