Vehicles With ABS
DTC 21: ABS SensorDTC 22: ABS Sensor
DTC 23: ABS Sensor
DTC 24: ABS Sensor
ABS-ECU Signal Line System Circuit (ABS Sensor System) <Vehicles with ABS>:
CIRCUIT OPERATION
^ The ABS-ECU detects the speed of each wheel according to the pulse signals from each ABS sensor.
^ The AWD-ECU receives the ABS sensor signals through the ABS-ECU.
DTC SET CONDITIONS
A diagnosis code 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 ABS-ECU
^ 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, read the ABS 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 ABS diagnostic trouble code.
4) Turn the ignition switch to the LOCK (OFF) position.
Q: Are DTCs (No.11, 12, 13, 14, 21, 22, 23, 24) set?
YES: Refer to ABS-Diagnostic Trouble Code Chart.
NO: Go to Step 2.
STEP 2. 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 3.
STEP 3. Measure the ABS sensor output voltage at AWD-ECU connector C-139 by backprobing.
1) Turn the ignition switch to the ON position.
2) Measure the voltage between the following terminals of AWD-ECU connector C-139 and ground while turning the relevant tire of the terminal being measured one-half to one turn per second.
^ Terminal 9
^ Terminal 6
^ Terminal 7
^ Terminal 8
^ The voltage changes between 0 Volts and 5 Volts.
3) Turn the ignition switch to the LOCK (OFF) position.
Q: Does the voltage change between 0 Volts and 5 Volts?
YES: Go to Step 7.
NO: Go to Step 4.
STEP 4. Check ABS-ECU connector B-118 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-ECU connector B-118 (terminals 9, 6, 7, 8) and AWD-ECU connector C-139 (terminals 18, 32, 21, 20).
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 MB9911958, check data list item 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
^ The speedometer indication matches the M.U.T.-III indication.
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 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 6.
NO: Repair or replace the damaged components.