[35B] ANTI-SKID BRAKING SYSTEM (ABS) - - TROUBLESHOOTING - DIAGNOSTIC TROUBLE CODE PROCEDURES - Code No. 21, 22, 23, 24: ABS Sensor | PRINT PAGE / INDEX / PRIOR / NEXT

Code No. 21, 22, 23, 24: ABS Sensor
CIRCUIT OPERATION A toothed ABS rotor generates a voltage pulse as it moves across the pickup field of each ABS sensor. The amount of voltage generated at each wheel is determined by the clearance between the ABS rotor teeth and the ABS sensor, and by the speed of rotation. The ABS sensors transmit the frequency of the voltage pulses and the amount of voltage generated by each pulse to the ABS electronic control unit (ABS-ECU). The ABS hydraulic unit modulates the amount of braking force individually applied to each wheel cylinder.
DIAGNOSIS CODE SET CONDITIONS Diagnosis codes No. 21, 22, 23 and 24 are output in the following cases: Open circuit is not found but no input is received by one or more of the four ABS sensors at 10 km/h or more. ABS sensor output drops due to a malfunctioning ABS sensor or warped ABS rotor.
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THESE DIAGNOSIS CODES ARE TO SET ARE:) Malfunction of the ABS sensor Damaged wiring harness or connector Malfunction of the hydraulic unit (integrated with ABS-ECU) Malfunction of the ABS rotor Malfunction of the wheel bearing Excessive clearance between the ABS sensor and ABS rotor Teeth lack or clogging of the ABS rotor
| DIAGNOSIS
| STEP 1. MUT-II/III data list. Set MUT-II/III to data reading mode, and check the data list items by driving the vehicle. Item 01: Front right ABS sensor Item 02: Front left ABS sensor Item 03: Rear right ABS sensor Item 04: Rear left ABS sensor OK: The reading on the speedometer nearly matches the indication on MUT-II/III, when driving. Q: Is the ABS sensor input normal? YES: This malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope With Intermittent Malfunction . NO: Go to Step 2.
| STEP 2. Check the ABS sensor installation. Q: Is the ABS sensor bolted securely in place at the front knuckle or the trailing arm? YES: Go to Step 3. NO: Install it properly (Refer to .) and go to Step 11 .
| STEP 3. Inspect the ABS sensor and ABS rotor. Refer to . Check items: ABS sensor internal resistance: 1.24 - 1.64 kΩ Insulation between the ABS sensor body and the connector terminals Toothed ABS rotor check Q: Is the ABS sensor or ABS rotor damaged? YES: Replace it and then go to Step 11. NO: Go to Step 4.
| STEP 4. Measure the resistance at the ABS-ECU connector B-03. Disconnect the connector B-03 and measure at the harness side. Measure the resistance between the ABS-ECU connector terminals 16 and 26, 9 and 10, 11 and 17, or 27 and 28. Standard Value: 1.24 - 1.64 kΩ Q: Is the resistance between terminals 16 and 26, 9 and 10, 27 and 28, or 11 and 17 within the standard value? When resistances between all terminals are within the standard value.: Go to Step 9. When resistance between terminals 16 and 26 is not within the standard value.: Go to Step 5. When resistance between terminals 9 and 10 is not within the standard value.: Go to Step 6. When resistance between terminals 27 and 28 is not within the standard value.: Go to Step 7. When resistance between terminals 11 and 17 is not within the standard value.: Go to Step 8.
| STEP 5. Check the harness wires between ABS-ECU connector B-03 (terminals 16 and 26) and ABS sensor <front: LH> connector A-13 (terminals 1 and 2). NOTE: After inspecting ABS-ECU connector B-03, intermediate connector A-14 and ABS sensor <front: LH> connector A-13, inspect the wire. If ABS-ECU connector B-03, intermediate connector A-14 and ABS sensor <front: LH> connector A-13 are damaged, repair or replace them. Then go to Step 11. Q: Is the harness wire between ABS-ECU connector B-03 (terminals 16 and 26) and ABS sensor <front: LH> connector A-13 (terminals 1 and 2) damaged? YES: Repair it and go to Step 11. NO: Go to Step 11.
| STEP 6. Check the harness wires between ABS-ECU connector B-03 (terminals 10 and 9) and ABS sensor <front: RH> connector A-30 (terminals 1 and 2). NOTE: After inspecting ABS-ECU connector B-03, intermediate connector C-14, C-104 and ABS sensor <front: RH> connector A-30, inspect the wire. If ABS-ECU connector B-03, intermediate connector C-14, C-104 and ABS sensor <front: RH> connector A-30 are damaged, repair or replace them. Then go to Step 11. Q: Is the harness wire between ABS-ECU connector B-03 (terminals 10 and 9) and ABS sensor <front: RH> connector A-30 (terminals 1 and 2) damaged? YES: Repair it and go to Step 11. NO: Go to Step 11.
| STEP 7. Check the harness wires between ABS-ECU connector B-03 (terminals 28 and 27) and ABS sensor <rear: LH> connector D-21 (terminals 1 and 2). NOTE: After inspecting ABS-ECU connector B-03, intermediate connector C-104, C-117, D-22 and ABS sensor <rear: LH> connector D-21, inspect the wire. If ABS-ECU connector B-03, intermediate connector C-104, C-117, D-22 and ABS sensor <rear: LH> connector D-21 are damaged, repair or replace them. Then go to Step 11. Q: Is the harness wire between ABS-ECU connector B-03 (terminals 28 and 27) and ABS sensor <rear: LH> connector D-21 (terminals 1 and 2) damaged? YES: Repair it and then go to Step 11. NO: Go to Step 11.
| STEP 8. Check the harness wires between ABS-ECU connector B-03 (terminals 11 and 17) and ABS sensor <rear: RH> connector D-12 (terminals 1 and 2). NOTE: After inspecting ABS-ECU connector B-03, intermediate connector C-104, C-117, D-22 and ABS sensor <rear: RH> connector D-12, inspect the wire. If ABS-ECU connector B-03, intermediate connector C-104, C-117, D-22 and ABS sensor <rear: RH> connector D-12 are damaged, repair or replace them. Then go to Step 11. Q: Is the harness wire between ABS-ECU connector B-03 (terminals 11 and 17) and ABS sensor <rear: RH> connector D-12 (terminals 1 and 2) damaged? YES: Repair it and then go to Step 11. NO: Go to Step 11.
| STEP 9. Check the ABS sensor output voltage. Refer to . Output Voltage: When measured with a voltmeter: 42 mV or more When measured with an oscilloscope (maximum voltage): 200 mV or more Q: Does the voltage meet the specification? YES: Erase the diagnosis code memory, and recheck if any diagnosis code sets. If diagnosis code No. 21, 22, 23 or 24 sets, replace the hydraulic unit (integrated with ABS-ECU). Then go to Step 11. NO: Go to Step 10.
| STEP 10. Check the wheel bearing. <Front>: Refer to GROUP 26, On-vehicle Service - Wheel Bearing Play Check . <Rear>: Refer to GROUP 27A, On-vehicle Service - Wheel Bearing Play Check <2WD>. Or refer to GROUP 27B, On-vehicle Service - Wheel Bearing Play Check <4WD>. Q: Is the check result normal? YES: Go to Step 11. NO: Replace it and then go to Step 11.
| STEP 11. Check whether the diagnosis code is reset. Q: Do the diagnosis codes No. 21, 22, 23 or 24 reset? YES: Go to Step 1. NO: The procedure is complete.

[35B] ANTI-SKID BRAKING SYSTEM (ABS) - - TROUBLESHOOTING - DIAGNOSTIC TROUBLE CODE PROCEDURES - Code No. 21, 22, 23, 24: ABS Sensor | PRINT PAGE / INDEX / PRIOR / NEXT

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