ABS

C2112

Component Location:

General Description
The ABS ECU supplies battery power to all solenoid valves by way of a valve relay which is controlled by the Electronic Control UNIT (ECU). The valve relay and all solenoid valves are installed inside the HECU (Hydraulic and Electronic Control Unit).

DTC Description
ABS ECU monitors voltage of the valve relay to check if ABS ECU can perform ABS control normally. When the valve relay is switched to ON, the HECU will set this code if the solenoid drive voltage is below permissible voltage ranges for a period of time. When the valve relay is switched to OFF, the HECU sets this code if the solenoid drive voltage is over the permissible voltage range for a period of time.

DTC Detecting Condition:

Schematic Diagram:

Monitor Actuation Test
1. Connect scantool to Data Link Connector (DLC)
2. Ignition "ON" & Engine "OFF".
3. Select the "Actuation Test" mode on the scantool.
4. Inspect operating status of all valves with Actuation Test.

Specification : It's normal if operating sound is heard.






5. Do all valves operate normally?

YES
a. Fault is intermittent caused by poor connection in power harness (ABS1) and/or HECU's connector or was repaired and HECU memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

NO
a. Go to "W/Harness Inspection" procedure.

Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness (es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?

YES
a. Repair as necessary and then go to "Verification of Vehicle Repair" procedure.

NO
a. Go to "Power Circuit Inspection" procedure.

Power Supply Circuit Inspection
1. Ignition "OFF"
2. Disconnect HECU connector.
3. Ignition "ON".
4. Measure voltage between terminal "25" of the HECU harness connector and chassis ground.

Specification : Approx. B+






5. Is the measured voltage within specifications?

YES
a. Go to "Ground Circuit Inspection" procedure.

NO
a. Check for poor connection in the power supply harness between the battery terminal (+) and the terminal "25" of the HECU harness connector. Check for open or blown 30 A ABS fuse referring to "Circuit Diagram". Repair as necessary and then go to "Verification of vehicle Repair" procedure.

Ground Circuit inspection
1. Ignition "OFF".
2. Disconnect HECU connector.
3. Measure resistance between terminal "8,24" of the HECU harness connector and chassis ground.

Specification : Approx. below 1 ohm






4. Is the measured resistance within specifications?

YES
a. Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.

NO
a. Check for damaged harness and poor connection between terminal "8,24" of the HECU harness connector and chassis ground. Repair as necessary and then go to "Verification of vehicle Repair" procedure.

Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Using a Scantool, Clear DTC.
3. Operate the vehicle within DTC Detecting Condition in General Information.
4. Are any DTCs present?

YES
a. Go to the applicable troubleshooting procedure.

NO
a. System performing to specification at this time.