- Turn ignition on. Using a DVOM, measure voltage between breakout box pins No. 2 and 40. If voltage is more than 10 volts, go to step 5). If voltage is less than 10 volts, go to next step.
- Check fuse No. 22 to "ANTI-LOCK" light and vehicle battery. Turn ignition off. Disconnect positive battery cable. Check for continuity between pin No. 40 and ground. If continuity is present, go to next step. If continuity is not present, repair wire harness.
- Check for continuity between pin No. 2 and ignition switch Yellow wire (single connector). If continuity is present, reconnect positive battery cable and go to next step. If continuity is not present, repair wire harness.
- Turn ignition on. Check for battery voltage at ignition switch Yellow wire (single connector). If battery voltage is present, connect ECM wire harness connector to ECM. Recheck vehicle symptom. If battery voltage is not present, replace ignition switch. Check ABS system operation.
- Check for battery voltage between pins No. 2 and 40. If battery voltage is present, go to step 8). If battery voltage is not present, go to next step.
- Check for battery voltage at electronic control relay pin No. 30 on harness side. If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit between relay and ignition switch.
- Turn ignition off. Check for continuity between electronic control relay pin No. 87a (harness side) and breakout box pin No. 2. If continuity is present, replace electronic control relay. If continuity is not present, repair open circuit between relay and ECM.
- Check for continuity between breakout box pins No. 3 and 40. If continuity is present, go to step 12). If continuity is not present, go to next step.
- Disconnect main power (Green) relay from connector. Check for continuity between relay terminals No. 30 and 87a. If continuity is present, go to next step. If continuity is not present, replace main power relay.
- Disconnect positive battery cable. Check for continuity between main power relay pin No. 30 on harness side and breakout box pin No. 3. If continuity is present, go to next step. If continuity is not present, repair Blue/Green wire in harness.
- Check for continuity between main power relay pin No. 87a on harness side and ground. If continuity is present, install main power relay, ECM and battery cable. Recheck symptom. If continuity is not present, repair wire harness.
- Check for continuity between breakout box pins No. 20 and 40. If continuity is present, go to step 14). If continuity is not present, go to next step.
- Remove main power relay. Check for continuity between relay pin No. 30 on harness side and breakout box pin No. 20. If continuity is present, install main power relay and ECM. Recheck symptom. If continuity is not present, repair Blue/Green wire in harness.
- Turn ignition on. Measure resistance between breakout box pins No. 9 and 10. If resistance is less than 5 ohms, go to step 20). If resistance is more than 5 ohms, go to next step.
- Disconnect fluid level indicator 2-pin connector. Measure resistance across indicator terminals. If resistance is more than 2 ohms, go to next step. If resistance is less than 2 ohms, replace fluid level indicator.
- Ensure brake system is pressurized. Disconnect pressure warning switch 3-pin connector. Check for continuity between switch terminals No. 3 and 5. If continuity is present, go to next step. If continuity is not present, replace pressure warning switch.
- Check for continuity between breakout box pin No. 9 and fluid level indicator pin No. 1 on harness side. If continuity is present, go to next step. If continuity is not present, repair Brown/White wire in harness.
- Check for continuity between pin No. 2 of 2-pin fluid level indicator connector on harness side and pin No. 5 of 5-pin pressure warning switch connector on harness side. If continuity is present, go to next step. If continuity is not present, repair Brown/White wire in harness.
- Check for continuity between pin No. 5 of 5-pin pressure warning switch on harness side and breakout box pin No. 10. If continuity is present, turn ignition off. Connect all electrical connectors. Recheck symptom. If continuity is not present, replace Brown/Green wire in harness.
- Check for continuity between breakout box pin No. 9 and 10 in turn to ground. If continuity is present, go to next step. If continuity is not present, go to step 26).
- Ensure brake fluid level is at maximum level. Disconnect fluid level indicator 2-pin connector. Check for continuity between each terminal in turn to ground. If continuity is present, replace fluid level indicator. If continuity is not present, go to next step.
- Check for continuity between fluid level indicator pin No. 1 on harness side and ground. If continuity is present, repair Brown/White wire in harness. If continuity is not present, go to next step.
- Disconnect 5-pin pressure warning switch connector. Check for continuity between fluid level indicator pin No. 2 on harness side and ground. If continuity is present, repair Brown/White wire in harness. If continuity is not present, go to next step.
- Ensure brake system is pressurized. Check for continuity between pressure warning switch pin No. 3 and 5 in turn to ground. If continuity is present, replace pressure warning switch and pump motor relay. If continuity is not present, go to next step.
- Check for continuity between 5-pin pressure warning switch pin No. 5 on harness side and ground. If continuity is present, repair Brown/Green wire in harness. If continuity is not present, connect all electrical connectors. Recheck symptom.
- Turn ignition off. Measure resistance between breakout box pins No. 8 and 40. If resistance is 50-100 ohms, go to step 30). If resistance is not 50-100 ohms, go to next step.
- Remove main power (Green) relay. Measure resistance between relay terminals No. 85 and 86. If resistance is 50-100 ohms, go to next step. If resistance is not 50-100 ohms, replace main power relay.
- Check for continuity between main power relay pin No. 86 on harness side and breakout box pin No. 8. If continuity is present, go to next step. If continuity is not present, repair Blue/Green wire in harness.
- Check for continuity between main power relay terminal No. 85 and ground. If continuity is present, connect all electrical connectors. Recheck symptom. If continuity is not present, repair wire harness.
- Connect a jumper wire between breakout box pins No. 2 and 8. Turn ignition on. Measure voltage between breakout box pins 3 and 40. If voltage is more than 10 volts, remove jumper wire and go to step 33). If voltage is less than 10 volts, check fuse No. 19. Remove jumper wire. Go to next step.
- Turn ignition off. Remove main power relay. Using jumper wire, apply battery voltage to relay terminal No. 85 and ground relay terminal No. 86. Using a DVOM, check for continuity between relay terminals No. 30 and 87. If continuity is present, go to next step. If continuity is not present, replace main power relay.
- Check for continuity between main power relay harness connector pin No. 87 and battery positive terminal. If continuity is present, connect all electrical connectors. Recheck symptom. If continuity is not present, repair wire harness.
- Ensure ignition is off. Measure resistance between breakout box pins No. 4 and 22 (right rear wheel sensor), No. 5 and 23 (left front wheel sensor), 6 and 24 (left rear wheel senor) and No. 7 and 25 (right front wheel sensor). If resistance is 800-1400 ohms, go to next step. If resistance is not 800-1400 ohms, check corresponding wheel sensor circuit for continuity. If continuity is present, replace wheel sensor.
- Turn ignition off. Measure resistance between breakout box pins No. 11 and 18. If resistance is 2-5 ohms, go to step 36). If resistance is not 2-5 ohms, go to next step.
- Disconnect 2-pin main valve connector. Measure resistance across main valve terminals. If resistance is 2-5 ohms, repair wire harness. If resistance is not 2-5 ohms, replace hydraulic unit assembly as main valve cannot be replaced separately.
- Measure resistance between breakout box pins No. 11 and 40. If resistance is less than 2 ohms, go to step 39). If resistance is more than 2 ohms, go to next step.
- Disconnect 7-pin solenoid valve block connector. Measure resistance between solenoid valve block terminal No. 7 and ground. If resistance is less than 2 ohms, repair wire harness. If resistance is more than 2 ohms, go to next step.
- Disconnect negative battery cable. Check for continuity between valve body and ground. If continuity is present, replace solenoid valve block assembly for an internal ground problem. If continuity is not present, repair hydraulic unit ground strap.
- Measure resistance between breakout box pins indicated in SOLENOID VALVE BLOCK RESISTANCE table. If resistance is within specification, inlet and/or outlet valves are okay. Go to next step. If resistance is not within specification, see SOLENOID VALVE BLOCK TERMINAL RESISTANCE
. This table measures resistance directly at solenoid valve block assembly. If resistance measured at SOLENOID VALVE BLOCK TERMINAL RESISTANCE table is not within specification, replace solenoid valve block assembly. If resistance is within specification, repair wire harness.
SOLENOID VALVE BLOCK RESISTANCE
| Valve Application |
Breakout Box Pins |
Ohms |
| Right Front Inlet |
11 & 40 |
5-7 |
| Right Front Outlet |
11 & 34 |
3-6 |
| Left Front Inlet |
11 & 35 |
5-7 |
| Left Front Outlet |
11 & 16 |
3-5 |
| Rear Inlet |
11 & 15 |
5-7 |
| Rear Outlet |
11 & 33 |
3-5 |
SOLENOID VALVE BLOCK TERMINAL RESISTANCE
| Valve Application |
Valve Block Terminals |
Ohms |
| Right Front Inlet |
1 & 7 |
5-7 |
| Right Front Outlet |
2 & 7 |
3-6 |
| Left Front Inlet |
6 & 7 |
5-7 |
| Left Front Outlet |
5 & 7 |
3-6 |
| Rear Inlet |
3 & 7 |
5-7 |
| Rear Outlet |
4 & 7 |
3-5 |
- Ensure vehicle temperature is less than 70°F (21°C). Release brake system pressure. Turn ignition off. Depress brake pedal at least 20 times to depressurize brake system. Disconnect 5-pin pressure warning switch. Check for continuity between switch terminals No. 1 and 2. If continuity is present, go to next step. If continuity is not present, replace pressure warning switch, pump motor relay and diode.
- Connect 5-pin pressure warning switch connector. Turn ignition on. When pump motor stops, turn ignition off. Disconnect 5-pin pressure warning switch connector. Check for continuity between switch terminals No. 1 and 2. If continuity is present, replace pressure warning switch, motor relay and diode. If continuity is not present, go to next step.
CAUTION:
Before performing next step, ensure brake system pressure is fully discharged.
- Turn ignition off. Depress brake pedal at least 20 times to depressurize brake system. Place a shop rag around base of accumulator to catch brake fluid. Using an 8mm Allen wrench, remove accumulator from hydraulic unit. Install Pressure Gauge (T85P-20215-A) and Adapter (D88M-20215-A) to hydraulic unit. Install accumulator to adapter. Turn ignition on. Ensure brake fluid is not leaking. Pressure gauge should read 1450-1595 psi (102-112 kg/cm2
). If pressure is within specification, go to next step. If pressure is not within specification, replace pressure warning switch, pump motor relay and diode.
- Connect 5-pin pressure warning switch connector. Turn ignition on. When pump motor stops, disconnect 5-pin pressure warning switch connector. Slowly pump brake pedal (releasing system pressure) until continuity is read across switch terminals No. 1 and 2. When continuity is obtained, observe pressure gauge.
- Check for continuity between pressure warning switch harness connector pins No. 1 and ground. If continuity is present, go to next step. If continuity is not present, repair wire harness.
CAUTION:
Before performing next step, ensure brake system pressure is fully discharged.
- Connect all electrical connectors. Ensure ignition is off. Depress brake pedal at least 20 times to depressurize brake system. Place a shop rag around base of accumulator to catch brake fluid. Remove accumulator from adapter. Remove pressure gauge and adaptor from hydraulic unit. Install accumulator onto hydraulic unit using a new "O" ring. Recheck symptom. If symptom is no longer present, fault may have been a loose electrical connection. If symptom is still present, replace ECM.