Vehicles Without ABS
DTC 21: ABS SensorDTC 22: ABS Sensor
DTC 23: ABS Sensor
DTC 24: ABS Sensor
ABS Sensor System (Vehicle Without ABS):
CIRCUIT OPERATION
The AWD-ECU detects the speed of each wheel according to the pulse signals from each ABS sensor.
DTC SET CONDITIONS
A DTC corresponding to the open circuit or short circuit of the ABS sensor is set when one ABS sensor has detected a vehicle speed of above 15 km/h (9.3 mph), but any one of the remaining three ABS sensors could not detect the vehicle speed.
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)
^ Malfunction of the ABS sensor
^ 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. Using scan tool MB991958, check data list items 01, 02, 03, 04: ABS Sensor.
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) Start the engine.
3) Set scan tool MB991958 to the data reading mode.
^ Item 01: ABS Sensor
^ Item 02: ABS Sensor
^ Item 03: ABS Sensor
^ Item 04: ABS Sensor
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Go to Step 2.
STEP 2. Check the ABS sensor at ACD-ECU connector C-139.
1) Disconnect connector C-139 and measure at the harness side.
2) Measure the resistance between the following terminals.
^ Measure the resistance between terminal 9 and 22.
^ Measure the resistance between terminal 6 and 19.
^ Measure the resistance between terminal 7 and 20.
^ Measure the resistance between terminal 8 and 21.
Q: Is the measured resistance within the specified range?
YES: Go to Step 7.
NO: Go to Step 3.
STEP 3. Check the ABS sensor.
Q: Is the check result normal?
YES: Go to Step 4.
NO: Repair or replace the ABS sensor.
STEP 4. Check ABS sensor connector A-03, A-27, D-06, D-13, intermediate connector A-29, C-111, C-113, C-122, D-34 and AWD-ECU connector C-139 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 5.
NO: Repair or replace the damaged components.
STEP 5. Check the harness for open circuit or short circuit to ground between ABS sensor connector A-03 (terminals 1, 2), A-27 (terminals 1, 2), D-06 (terminals 1, 2), D-13 (terminals 1, 2) and AWD-ECU connector C-139 (terminals 6, 19, 9, 22, 7, 20, 8, 21).
Q: Is the harness wire in good condition?
YES: Go to Step 6.
NO: Repair or replace the harness wire.
STEP 6. Using scan tool MB991958, check data list items 01, 02, 03, 04: ABS Sensor.
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) Start the engine.
3) Set scan tool MB991958 to the data reading mode.
^ Item 01: ABS Sensor
^ Item 02: ABS Sensor
^ Item 03: ABS Sensor
^ Item 04: ABS Sensor
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Replace the AWD-ECU
STEP 7. Check the ABS sensor output voltage.
Q: Is the check result normal?
YES: Go to Step 10.
NO: Go to Step 8.
STEP 8. Check the ABS sensor and ABS rotor.
Q: Is the check result normal?
YES: Go to Step 9.
NO: Repair or replace the ABS sensor or ABS rotor.
STEP 9. Check the wheel bearing.
Q: Is the check result normal?
YES: Go to Step 6.
NO: Repair or replace the wheel bearing.
STEP 10. Check AWD-ECU connector C-139 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.