Test D
- Check brake lines, calipers, brake lines on hydraulic unit, reservoir seals and accumulator for brake fluid leakage. A small amount of fluid leakage is allowable from pressure warning switch. If no leakage is found, go to next step. If fluid leakage is found, repair as necessary.
- Turn ignition off. Depress brake pedal at least 20 times to depressurize brake system. Turn ignition on. Pump motor should operate. If pump motor operates, go to step 11). If pump motor does not operate, go to next step.
- Disconnect 2-pin pump motor connector. Turn ignition on. Check for voltage between pin No. 1 on harness side and ground. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, go to step 5).
- Turn ignition off. Check for continuity between pump motor harness connector pin No. 2 and ground. If continuity is present, check brake reservoir filter and/or suction hose. Repair as necessary. If continuity is not present, repair open in wire harness.
- Remove pump motor relay. Check for voltage between pin No. 30 on relay harness connector and ground. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair short to ground in wire harness.
- Turn ignition off. Check for continuity between pump motor relay harness connector pin No. 87 and pump motor connector pin No. 1. If continuity is present, go to next step. If continuity is not present, repair wire harness.
- Turn ignition off. Depress brake pedal at least 20 times to depressurize brake system. Disconnect 5-pin pressure warning switch. Check for continuity between pressure warning switch terminals No. 1 and 4. If continuity is present, go to next step. If continuity is not present, replace pressure warning switch, diode and pump motor relay.
- Check for continuity between pressure warning switch pin No. 1 on harness side and ground. If continuity is present, go to next step. If continuity is not present, repair wire harness.
- Check for continuity between motor relay terminals No. 30 and 87. If continuity is present, replace pump motor relay. If continuity is not present, go to next step.
- Using a jumper wire, apply battery voltage to pump motor relay terminal No. 85 and ground terminal No. 86. Check for continuity between relay terminals No. 30 and 87. If continuity is present, connect all electrical connectors. Recheck symptom. If continuity is not present, replace both motor relays, pressure warning switch and diode.
- Turn ignition off. Depress brake pedal at least 20 times to depressurize brake system. Connect a DVOM between battery positive cable and positive battery terminal. Turn off all electrical accessories. Turn ignition on. Measure pump motor current draw. If current is 0-25 amps, go to next step. If current draw is zero or more than 25 amps, replace pump motor unit, pressure warning switch, motor relay and diode.
- Turn ignition off. Depress brake pedal at least 20 times to depressurize brake system. Turn ignition on. Measure pump running time. If pump runs less than one minute, go to step 14). If pump runs more than one minute or pump motor never runs, go to next step.
- Turn ignition off. Disconnect low-pressure hose from pump allowing brake fluid to flow into a container. Brake fluid should flow freely. Discard drained brake fluid. If brake fluid flowed freely, connect low-pressure hose and fill reservoir. If brake fluid did not flow freely, repair or replace reservoir or low-pressure brake hose as necessary.CAUTION: Before performing next step, ensure brake system pressure is fully discharged.
- Ensure vehicle temperature is less than 70°F (21°C). 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 600-1325 psi (42-93 kg/cm2 ). If pressure is within specification, go to next step. If pressure is not within specification, replace accumulator.
- With pressure gauge attached and ignition on, pump brake pedal until pump motor restarts. If pressure is 1900-2200 psi (133-155 kg/cm2 ) when pump motor restarts, go to next step. If pressure is not 1900-2200 psi (133-155 kg/cm2 ) when pump motor restarts, replace pressure warning switch, diode and pump motor relay.
- Observe pressure when pump motor stops running. If pressure is 2350-2800 psi (165-197 kg/cm2 ) when motor stops, go to next step. If pressure is not 2350-2800 psi (165-197 kg/cm2 ) when motor stops, replace pressure warning switch, pump motor relays and diode.
- Disconnect 2-pin pump motor connector. Depress brake pedal until pressure is 1450-1595 psi (102-112 kg/cm2 ). "ANTI-LOCK" and "BRAKE" warning lights should illuminate. If lights illuminated, go to next step. If lights did not illuminate, replace pressure warning switch, pump relays and diode.
- Turn ignition on. When pump motor stops running, wait 3 minutes for pressure gauge to stabilize. Read pressure gauge. Wait 5 minutes and read pressure gauge again to determine pressure loss over 5 minutes. If pressure loss is less than 145 psi (10 kg/cm2 ), perform quick test. See Figure . If pressure loss is more than 145 psi (10 kg/cm2 ), replace hydraulic unit.