Component Testing: Abs-Ecu
NOTE:
DO NOT short circuit or check resistance of wrong terminals, as it may damage a sensor, wiring, or ABS-ECU.
- Leaving ABS-ECU connected, use a needle-nosed voltmeter wire probe to backprobe ABS-ECU terminals. Ensure voltage is as specified. See appropriate ABS-ECU VOLTAGE SPECIFICATIONS table. If voltage is as specified, go to next step. If voltage is not as specified, check related sensor, actuator and wiring. Repair as necessary.ABS-ECU VOLTAGE SPECIFICATIONS (AWD) (1)
Terminal No. (Description) and Check Condition Voltage 10 ("G" Sensor Input), Ignition On (2) Approx. 2.7 11 (Scan tool) Scan Tool Connected (3) Scan Tool Disconnected One Volt Or Less 12 (Input From Diagnosis Indication Selection) Scan Tool Connected Zero Scan Tool Disconnected Approx. 12 14 (Stoplight Switch Input) Ignition On, Stoplight Switch Off One Volt Or Less Ignition On, Stoplight Switch On System Voltage 15 (ABS-ECU Power Supply) Ignition On System Voltage Ignition In Start Zero 17 (Pump Motor Power Supply), At All Times System Voltage 18 (Solenoid Valve Power Supply), At All Times System Voltage 21 (Output To ABS Warning Light) Ignition On, Light Switch Off System Voltage Ignition On, Light Is Illuminated 0-2 28 ("G" Sensor Voltage out), Ignition On Approx. 5 (1) Unless otherwise indicated, specifications are with ignition on, engine off. (2) With vehicle parked on level surface. (3) Serial communication with scan tool. ABS-ECU VOLTAGE SPECIFICATIONS (FWD)(1)Terminal No. (Description) and Check Condition Voltage 11 (Scan tool) Scan Tool Connected (2) Scan Tool Disconnected One Volt Or Less 12 (Input From Diagnosis Indication Selection) Scan Tool Connected Zero Scan Tool Disconnected Approx. 12 14 (Stoplight Switch Input) Ignition On, Stoplight Switch Off One Volt Or Less Ignition On, Stoplight Switch On System Voltage 15 (ABS-ECU Power Supply) Ignition On System Voltage Ignition In Start Zero 17 (Pump Motor Power Supply), At all times System Voltage 18 (Solenoid Valve Power Supply), At All Times System Voltage 21 (Output To ABS Warning Light) Ignition On, Light Switch Off System Voltage Ignition On, Light Is Illuminated 0-2 (1) Unless otherwise indicated, specifications are with ignition on, engine off. (2) Serial communication with scan tool. - Ensure ignition is off. Disconnect ABS-ECU connector. Using an ohmmeter, check resistance between indicated ABS-ECU wiring harness terminals. Use Adapter Harness (MB991223) for checking contact pin pressure instead of inserting a test probe. See appropriate ABS-ECU RESISTANCE SPECIFICATIONS table. If resistance is as specified, ABS-ECU is okay. If resistance is not as specified, check related sensor, actuator and wiring. Repair as necessary.
ABS-ECU RESISTANCE SPECIFICATIONS (AWD)
| Terminals No. (Description) | Check Condition | Ohms |
|---|---|---|
| 1 & 2 (RR Wheel Speed Sensor) | Ignition Off | 1000-1500 |
| 4 & 5 (RF Wheel Speed Sensor) | Ignition Off | 1000-1500 |
| 6 & 7 (LF Wheel Speed Sensor) | Ignition Off | 1000-1500 |
| 8 & 9 (LR Wheel Speed Sensor) | Ignition Off | 1000-1500 |
| 16 & Body Ground (ABS-ECU Ground) | At All Times | Continuity |
| 19 & Body Ground (ABS-ECU Ground) | At All Times | Continuity |
| 30 & Body Ground ("G" Sensor Ground) | At All Times | Continuity |
ABS-ECU RESISTANCE SPECIFICATIONS (FWD)
| Terminals No. (Description) | Check Condition | Ohms |
|---|---|---|
| 1 & 3 (RR Wheel Speed Sensor) | Ignition Off | 1000-1500 |
| 4 & 5 (RF Wheel Speed Sensor) | Ignition Off | 1000-1500 |
| 6 & 7 (LF Wheel Speed Sensor) | Ignition Off | 1000-1500 |
| 8 & 9 (LR Wheel Speed Sensor) | Ignition Off | 1000-1500 |
| 16 & Body Ground (ABS-ECU Ground) | At All Times | Continuity |
| 19 & Body Ground (ABS-ECU Ground) | At All Times | Continuity |