BLEEDING BRAKE SYSTEM
Note. For specific brake bleeding procedure, see appropriate ANTI-LOCK article.
Note. Perform bleeding procedure on TRAC system if repairing master cylinder or traction control system.
Traction Control (TRAC) System
- Ensure master cylinder reservoir is full of brake fluid. Disconnect harness connector from pump. Connect auxiliary test harness to pump. (Scheme 48) Remove battery cover and air cleaner inlet. Remove air cleaner assembly with hose.
- Connect tube to bleeder screw on TRAC actuator. (Scheme 49) Loosen bleeder screw. Connect auxiliary test harness to battery. Bleed fluid with pump operating. (Scheme 50) Tighten bleeder screw. Operate pump for additional 30 seconds. Fill reservoir. Remove test harness. Clear diagnostic trouble codes. See «CLEARING DIAGNOSTIC TROUBLE CODES (DTCS)»(ref-124943-S34206223592001100400000).
Scheme 48
Scheme 49
Scheme 50
TRAC SYSTEM DOES NOT OPERATE
| CAUTION | If ECU replacement is instructed in following testing, always ensure ECU connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECU malfunction. |
Ensure no DTCs are present. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Inspect IG power supply circuit. See DTC 41: IG POWER SOURCE CIRCUIT in appropriate ANTI-LOCK BRAKES article. Inspect hydraulic lines for leakage. Repair as needed. Inspect speed sensor circuit(s). See DTC 31 , 32, 33 OR 34: SPEED SENSOR CIRCUIT in appropriate ANTI-LOCK article. On GS300, check Park/Neutral position switch circuit. See DTC P1780: PARK/NEUTRAL POSITION SWITCH MALFUNCTION article in AUTOMATIC TRANSMISSION. If all preceding tests are okay, replace ABS/TRAC ECU and TRAC ECU.
SLIP INDICATOR LIGHT MALFUNCTION (EXCEPT GS300)
Inspect slip indicator light circuit. See SLIP INDICATOR LIGHT CIRCUIT . Repair as needed.
TRAC INDICATOR LIGHT MALFUNCTION (GS300)
| CAUTION | If ECU replacement is instructed in following testing, always ensure ECU connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECU malfunction. |
Inspect TRAC indicator light circuit. See TRAC INDICATOR LIGHT CIRCUIT. Repair as needed. If circuit is okay, replace TRAC ECU.
TRAC OFF INDICATOR LIGHT MALFUNCTION
| CAUTION | If ECU replacement is instructed in following testing, always ensure ECU connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECU malfunction. |
Inspect TRAC OFF indicator light circuit. See TRAC OFF INDICATOR, TRAC CUT SWITCH CIRCUIT. Repair as needed. If circuit is okay, inspect TRAC cut switch circuit. If all preceding tests are okay, replace ABS/TRAC ECU and TRAC ECU.
DTCS CANNOT BE RETRIEVED
| CAUTION | If ECU replacement is instructed in following testing, always ensure ECU connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECU malfunction. |
On all models except GS300, inspect TRAC OFF indicator light circuit. Repair as needed. See TRAC OFF INDICATOR, TRAC CUT SWITCH CIRCUIT. If TRAC OFF indicator light circuit is okay, inspect Tc terminal circuit. See Tc TERMINAL CIRCUIT. If all preceding tests are okay, replace ABS/TRAC ECU and TRAC ECU.
On GS300, inspect TRAC indicator light circuit. Repair as needed. See TRAC INDICATOR LIGHT CIRCUIT. If TRAC indicator light circuit is okay, inspect Tc terminal circuit. See Tc TERMINAL CIRCUIT. If all preceding tests are okay, replace TRAC ECU.
SLIP INDICATOR LIGHT CIRCUIT
Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see appropriate wiring diagram in WIRING DIAGRAMS .
Tc TERMINAL CIRCUIT
| CAUTION | If ECU replacement is instructed in following testing, always ensure ECU connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECU malfunction. |
Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see appropriate wiring diagram in WIRING DIAGRAMS .
TRAC INDICATOR LIGHT CIRCUIT (GS300)
| CAUTION | If ECU replacement is instructed in following testing, always ensure ECU connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECU malfunction. |
Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see appropriate wiring diagram in WIRING DIAGRAMS .
TRAC OFF INDICATOR, TRAC CUT SWITCH CIRCUIT
Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see appropriate wiring diagram in WIRING DIAGRAMS .
* PLEASE READ FIRST *
| CAUTION | If vehicle is equipped with air suspension, turn air suspension switch off before lifting vehicle. Air suspension switch is located inside trunk, on left side. |
TRAC ACCUMULATOR & PUMP
| WARNING | When replacing accumulator, proper disposal methods must be followed. Loosen gas plug about 2 turns to a position where gas can leak out. After confirming all gas has been drained, remove gas plug and dispose of accumulator. Repeat operation if all gas is not released. Improper disposal can cause injury. |
| CAUTION | Hydraulic system is under high pressure. Use caution when opening hydraulic system. |
- Relieve high pressure fluid from accumulator. Remove air cleaner if necessary. Carefully disconnect brakeline from accumulator. Remove bolts and accumulator and pump assembly. Separate accumulator and pump. (Scheme 51), (Scheme 52) or (Scheme 53).
- To install, reverse removal procedure. Tighten assembly mounting bolts. See «TORQUE SPECIFICATIONS»(ref-124943-S24504191432001100400000). Use 2 NEW "O" rings when installing union bolt and pressure hose onto pump and accumulator. Bleed brake and TRAC systems. See «BLEEDING BRAKE SYSTEM»(ref-124943-S10226831212001100400000).
Scheme 51
Scheme 52
Scheme 53
TRAC ACTUATOR
- Remove air cleaner, charcoal canister and ducting. Disconnect TRAC solenoid relay if necessary. Carefully disconnect brakelines from actuator. Remove bolts and actuator assembly. (Scheme 54), (Scheme 55) or (Scheme 56).
- To install, reverse removal procedure. Tighten assembly mounting bolts. See «TORQUE SPECIFICATIONS»(ref-124943-S24504191432001100400000). Bleed brake and TRAC systems. See «BLEEDING BRAKE SYSTEM»(ref-124943-S10226831212001100400000).
