Electronic Steering System Lincoln Town Car III

DESCRIPTION & OPERATION

Electronic Variable Orifice (EVO) system is designed to regulate power steering effort according to vehicle speed and steering wheel rotation rate. System provides full assist at low vehicle speed for light parking effort, and minimum assist at high vehicle speed for improved handling and road feel. Full power steering assist returns during evasive maneuvers.

During periods of system malfunction, system will provide full power steering assist at all times. Diagnostic codes are accessible through service diagnostic connector. EVO system consists of speed and steering sensors, air suspension/EVO steering control module, actuator and interconnecting wiring. (Scheme 2)

Air suspension and EVO steering control modules are integrated. Steering wheel rotation sensor and Vehicle Speed Sensor (VSS) feed information to air suspension/EVO steering control module, which regulates EVO actuator valve assembly on power steering pump. Steering wheel rotation sensor is an optical or photocell sensor located at lower end of steering column. Sensor mounts on steering column and establishes rate of steering wheel rotation. Sensor and sensor ring are removed separately.

VSS is mounted on transmission and sends electrical signals to control module. Current produced by sensor increases and decreases linearly, according to vehicle speed. Current is constant at vehicle speed of 88 MPH or more. EVO actuator assembly generates a differential pressure, according to flow and current input, to control spool valve in power steering pump.

EVO is inside actuator valve. Air suspension/EVO steering control module contains a microprocessor, which analyzes input signals from VSS and steering wheel rotation sensor.

SYSTEM TESTS

Note. Before testing, check fluid level, belt tension, pump pulley, tire pressure and engine idle speed.

Minimum Flow Test

1. Connect Power Steering System Analyzer (014-00207) between pressure line and pump, with gauge between pump and tester valve. Add power steering fluid if needed. Start engine and allow to idle for approximately 2 minutes with idle set to specification. Record flow, gallons/minute (liters/minute).
2. If flow is less than 1.4 gallons/minute (5.3 liters/minute), power steering pump may require service, but continue diagnosis. If pressure is greater than 150 psi (10.5 kg/cm 2 ) at idle, check hoses for restrictions.
3. Partially close gate valve on tester to build up pressure to 740 psi (52.0 kg/cm 2 ). Observe and record flow. If flow is less than 1.4 gallons/minute (5.3 liters/minute), service or replace power steering pump. See «POWER STEERING PUMP FLOW TEST SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system) table. Proceed to «RELIEF PRESSURE TEST»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__relief-pressure-test) .

Relief Pressure Test

1. With power steering analyzer still connected, completely close and partially open gate valve 3 times. DO NOT allow valve to remain closed for more than 5 seconds.
2. Observe and record pressure. If pressure is not within relief pressure specification, replace power steering pump assembly. See «POWER STEERING PUMP PRESSURE TEST SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system) table.
3. Increase idle to approximately 1500 RPM. Observe and record flow. If flow is greater than maximum flow specification, replace pump assembly. See «POWER STEERING PUMP FLOW TEST SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system) table.
4. Return engine to idle. Have an assistant turn steering wheel to left and right stop. Record pressure and flow at both stops. Pressure developed at both stops should be approximately equal to maximum pressure recorded when closing gate valve.
5. Flow should now drop to less than .5 gallon/minute (1.9 liters/minute). If pressure is less than specified or flow is greater than specified, excessive internal leakage is indicated. Remove and overhaul power steering gear.
6. Have an assistant turn steering wheel slightly in both directions and then release quickly. Observe pressure gauge. Pressure should start climbing from minimum flow pressure and snap back to minimum when steering wheel is released.
7. If pressure drops slowly or sticks, steering gear is sticking or steering column is binding. Check column prior to steering gear replacement. Also check steering linkage and ball joints and repair or replace as necessary. Remove analyzer and reconnect pressure line.

POWER STEERING PUMP PRESSURE TEST SPECIFICATIONS

POWER STEERING PUMP FLOW TEST SPECIFICATIONS

STEERING WHEEL TURNING EFFORT CHECK

1. Ensure front wheels are properly aligned and tire pressure is correct before performing procedure. Park vehicle on dry concrete and set parking brake. Allow engine to idle 2-3 minutes to warm power steering fluid to operating temperature.
2. With engine running, attach a pull gauge to rim of steering wheel, and measure pull required to turn steering wheel one revolution in each direction from center. Steering wheel static turning effort should be approximately 6.0 lbs. (2.72 kg).

ENTERING EVO DIAGNOSTICS

1. Connect New Generation Star (NGS) Tester (007-00500) to Data Link Connector (DLC). DLC is located under instrument panel, near steering column. To enter EVO diagnostics, turn ignition off.
2. Following NGS tester manufacturer's instructions, establish communications with vehicle. If communications cannot be established, perform DATA LINK DIAGNOSTIC TEST as described in NGS tester manual.
3. If NGS tester displays CKT914, CKT915 or CKT70=ALL ECUS NO RESP/NOT EQUIP, see appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT.
4. Following NGS tester manufacturer's instructions, establish communications with air suspension/EVO steering control module. If NGS tester displays NO RESP/NOT EQUIP, go to «TEST F»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__test-f-no-communication-with-control) under DIAGNOSTIC TESTS.

RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES

1. If NGS tester displays SYSTEM PASSED, retrieve and record all continuous Diagnostic Trouble Codes (DTCs) stored in memory. Following NGS tester instructions, clear all DTCs and perform auto-test. See ELECTRONIC - TOWN CAR article in SUSPENSION.
2. Retrieve and record all stored DTCs. See «DIAGNOSTIC TROUBLE CODE & SYMPTOM INDEX»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system) table. If any "B" or "C" DTCs not listed in index are retrieved, go to ELECTRONIC - TOWN CAR article in SUSPENSION.
3. Service all DTCs in order listed. After completion of repairs, clear all DTCs using NGS tester. Check system for normal operation. Repeat auto-test.

DIAGNOSTIC TROUBLE CODE & SYMPTOM INDEX

Note. EVO system is combined with air suspension system. For diagnosis and testing not covered in this article, see ELECTRONIC - TOWN CAR article in SUSPENSION.

CONNECTOR IDENTIFICATION

Use illustration to identify terminals referenced in testing. (Scheme 1)

Scheme 1

TEST A: DTC C1441 & C1442 - STEERING SENSOR CIRCUIT FAILURE

Note. To identify terminals refereenced in testing, see CONNECTOR IDENTIFICATION. To identify circuits referenced in testing, see WIRING DIAGRAMS .

1. Turn ignition off. Inspect fuse No. 8 (10-amp) in fuse junction panel. Fuse junction panel is located behind left side of instrument panel. If fuse is okay, go to next step. If fuse is faulty, replace fuse and retest system for normal operation. If fuse fails again, repair short to ground. See «WIRING DIAGRAMS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system). After repair, retest system for normal operation.
2. Disconnect air suspension/EVO control module harness connector C250. Turn ignition on. Using digital multimeter set to diode test mode, connect positive multimeter lead to harness connector C250 terminal No. 18 (Red wire). (Scheme 1) Connect multimeter negative lead to ground. Turn steering wheel repeatedly at least a quarter turn in each direction. Multimeter should emit an audible beep as steering wheel is turned in each direction. If multimeter reacts as described, go to next step. If multimeter does not react as described, go to step 4.
3. Using digital multimeter set to diode test mode, connect positive multimeter lead to harness connector C220 terminal No. 19 (Brown wire). (Scheme 1) Connect multimeter negative lead to ground. Turn steering wheel repeatedly at least a quarter turn in each direction. If multimeter emits an audible beep as steering wheel is turned in each direction, replace control module. See «AIR SUSPENSION/EVO STEERING CONTROL MODULE»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__air-suspensionevo-steering-control-module) under REMOVAL & INSTALLATION. Retest system for normal operation. If multimeter does not react as described, go to step 9.
4. Turn ignition off. Disconnect steering wheel rotation sensor harness connector. Turn ignition on. Measure voltage between steering wheel rotation sensor harness connector Black and White/Purple wire terminals. If less than 10 volts exist, go to next step. If 10 volts or greater exist, go to step 6.
5. Measure voltage between ground and steering wheel rotation sensor harness connector Red wire terminal. If less than 10 volts exist, repair White/Purple wire as necessary. If 10 volts or greater exist, repair Black wire as necessary. After repair, test system for normal operation.
6. Measure voltage between ground and Red wire terminal of steering wheel rotation sensor harness connector. If voltage does not exist, go to next step. If any voltage exists, repair short to power in Red wire. Retest system for normal operation.
7. Measure resistance between ground and Red wire terminal of steering wheel rotation sensor harness connector. If resistance is greater than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in Red wire. Retest system for normal operation.
8. Measure resistance of Red wire between air suspension/EVO control module harness connector C250 terminal No. 18 and terminal of steering wheel rotation sensor harness connector. If resistance is 5 ohms or greater, repair open in Red wire. If resistance is less than 5 ohms, replace steering wheel rotation sensor. See «STEERING WHEEL ROTATION SENSOR & RING»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system) under REMOVAL & INSTALLATION. After repair, retest system for normal operation.
9. Measure voltage between ground and Brown wire terminal of steering wheel rotation sensor harness connector. If voltage does not exist, go to next step. If any voltage exists, repair short to power in Brown wire. Retest system for normal operation.
10. Measure resistance between ground and Brown wire terminal of steering wheel rotation sensor harness connector. If resistance is greater than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in Brown wire. Retest system for normal operation.
11. Measure resistance of Brown wire between air suspension/EVO control module harness connector C250 terminal No. 19 and terminal of steering wheel rotation sensor harness connector. If resistance is 5 ohms or greater, repair open in Brown wire. If resistance is less than 5 ohms, replace steering wheel rotation sensor. See «STEERING WHEEL ROTATION SENSOR & RING»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system) under REMOVAL & INSTALLATION. After repair, retest system for normal operation.

TEST B: DTC C1897 - STEERING VAPS II CIRCUIT LOOP FAILURE

Note. EVO actuator valve assembly may also be referred to as power steering control valve actuator.

1. Turn ignition off. Disconnect power steering EVO actuator valve assembly harness connector. Inspect connector and pigtail damage or corrosion. If connector and pigtail are okay, go to next step. If problem is found, repair or replace as necessary. Retest system for normal operation.
2. Measure resistance between power steering control valve actuator Tan/Yellow wire terminal and ground. If resistance is greater than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, replace power steering EVO actuator valve assembly. See «EVO ACTUATOR VALVE ASSEMBLY»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__evo-actuator-valve-assembly). Retest system for normal operation.
3. Measure resistance between power steering EVO actuator valve terminals. If resistance is 4-8 ohms, go next step. If resistance is not 4-8 ohms, replace power steering control valve actuator. See «EVO ACTUATOR VALVE ASSEMBLY»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__evo-actuator-valve-assembly).
4. Turn ignition off. Disconnect air suspension/EVO power steering control module harness connector C251. Measure voltage between power steering control valve actuator harness connector Tan/Yellow wire terminal and ground. If any voltage exists, repair short to power in Tan/Yellow wire. Retest system for normal operation. If voltage does not exist, go to next step.
5. Measure voltage between power steering EVO actuator valve assembly harness connector Gray/Orange wire terminal and ground. If any voltage exists, repair short to power in Gray/Orange wire. Retest system for normal operation. If voltage does not exist, go to next step.
6. Measure resistance between power steering EVO actuator valve assembly harness connector Tan/Yellow wire terminal and ground. If resistance is 10 k/ohms or greater, go to next step. If resistance is less than 10 k/ohms, repair short to ground in Tan/Yellow wire. Retest system for normal operation.
7. Measure resistance between power steering EVO actuator valve assembly harness connector Gray/Orange wire terminal and ground. If resistance is 10 k/ohms or greater, go to next step. If resistance is less than 10 k/ohms, repair short to ground in Gray/Orange wire. Retest system for normal operation.
8. Measure resistance of Tan/Yellow wire between power steering control valve actuator harness connector and air suspension/EVO steering control module connector C251 terminal No. 26. (Scheme 1) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open in Tan/Yellow wire. Retest system for normal operation.
9. Measure resistance of Gray/Orange wire between power steering control valve actuator harness connector and air suspension/EVO steering control module harness connector C251 terminal No. 14. If resistance is less than 5 ohms, replace control module. See «AIR SUSPENSION/EVO STEERING CONTROL MODULE»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__air-suspensionevo-steering-control-module) under REMOVAL & INSTALLATION. Retest If resistance is 5 ohms or greater, repair open in Gray/Orange wire. Retest system for normal operation.

TEST C: STEERING VERY DIFFICULT/VERY EASY

1. Start engine and allow it to idle. Inspect power steering pump for leaks while rotating steering wheel in both directions. Perform pressure and flow tests on power steering pump. See «HYDRAULIC SYSTEM PRESSURE & FLOW TEST»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system) . If power steering pump is okay, go to next step. If power steering pump is faulty, replace pump and retest system for normal operation.
2. Visually inspect steering linkage while assistant turns steering wheel in both directions. If linkage moves smoothly from side to side, go to next step. If problem is found, repair as necessary. Retest system for normal operation.
3. Inspect ball joints for wear and looseness. See FRONT - CROWN VICTORIA, GRAND MARQUIS & TOWN CAR article in SUSPENSION. If no problem is found, go to next step. If problem is found, replace ball joints and retest system for normal operation.
4. Visually inspect steering gear operation while assistant turns steering wheel from stop to stop. Check for loose steering gear mountings, worn rubber bushing or any excessive movement. If problem is found, repair or replace as necessary. Retest system for normal operation. If no problem is found, but condition persists, diagnose by symptom.

TEST D: STEERING DOES NOT VARY WITH INCREASED WHEEL ROTATION

Start engine and allow it to idle. Inspect power steering pump for leaks while rotating steering wheel in both directions. Perform pressure and flow tests on power steering pump. See HYDRAULIC SYSTEM PRESSURE & FLOW TEST . If power steering pump is okay, check for kinked or blocked hoses to and from power steering pump. Replace hoses as necessary. If power steering pump is faulty, replace pump. After repair, retest system for normal operation.

TEST E: STEERING DOES NOT VARY WITH VEHICLE SPEED

1. Road test vehicle. Check speedometer/odometer operation. If speedometer/odometer operates properly, go to next step. If speedometer/odometer do not operate properly, see appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT to continue diagnosis.
2. Turn ignition off. Connect New Generation Star (NGS) Tester (007-00500) to Data Link Connector (DLC) located under instrument panel. Turn ignition on. Retrieve and record stored DTCs. If DTC U1041 is retrieved, go to ANTI-LOCK - TOWN CAR article in BRAKES. If any DTCs other than U1041 are retrieved, see ELECTRONIC - TOWN CAR article in SUSPENSION. If no DTCs are retrieved, replace air suspension/EVO steering control module. See «AIR SUSPENSION/EVO STEERING CONTROL MODULE»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__air-suspensionevo-steering-control-module) under REMOVAL & INSTALLATION. After repair, retest system for normal operation.

TEST F: NO COMMUNICATION WITH CONTROL MODULE

Note. Air suspension/EVO steering control module may also be referred to as simply control module.

1. Inspect fuse No. 8 (10-amp) in fuse junction panel. Fuse junction panel is located behind left side of instrument panel. Also inspect battery junction box fuse No. 17 (10-amp). Battery junction box is located at left rear of engine compartment. If fuses are okay, go to next step. If fuse(s) is faulty, replace fuse and retest system for normal operation. If fuse fails again, repair short to ground. See «WIRING DIAGRAMS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system). after repair, retest system for normal operation.
2. Turn ignition off. Disconnect air suspension/EVO control module connector C250. (Scheme 1) Measure voltage between ground and control module harness connector C250 terminal No. 16 (White/Purple wire). If 10 volts or greater exist, go next step. If less than 10 volts exist, repair open in White/Purple wire. Retest system for proper operation.
3. Measure voltage between ground and control module harness connector C250 terminal No. 1 (Dark Green/Yellow wire). If 10 volts or greater exist, go next step. If less than 10 volts exist, repair open in Dark Green/Yellow. Retest system for proper operation.
4. Turn ignition off. Measure resistance between ground and control module harness connector C250 terminal No. 6 (Black wire). If resistance is 5 ohms or greater, repair open in Black wire. If resistance is less than 5 ohms, see appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT. Retest system for proper operation.

CAPACITY

Fluid capacity is approximately 1.6 pts. (.75L).

FLUID TYPE

Use synthetic Mercon(R) ATF (E6AZ-19582-AA).

FLUID LEVEL CHECK

Check fluid level at least twice a year, or every 7500 miles. Clean dirt and grease from filler cap area to avoid fluid contamination. Check fluid level with engine off and fluid at operating temperature. Maintain fluid at MAX level in reservoir. DO NOT overfill.

Scheme 2

HYDRAULIC SYSTEM BLEEDING

Note. Abnormal noise originating from power steering system may be caused by air trapped in system.

1. Raise front wheels off ground, and support vehicle. Disconnect ignition coil wire. Crank engine for 30 seconds. Check fluid level and add if necessary. Crank engine again for 30 seconds while turning steering wheel from side to side several times. Avoid holding wheel in full left or right position. Check fluid level again and add if necessary.
2. Return wheels to center position. Reconnect ignition coil wire. Start and run engine for 2-3 minutes. Lower and road test vehicle. Recheck fluid level. Fluid containing air will have a milky appearance. All air should be eliminated to obtain normal steering. If air in system cannot be eliminated by cranking engine or driving vehicle, go to next step.
3. Check and fill reservoir to MAX mark. Disconnect and ground ignition coil lead. Raise and support front of vehicle. Crank engine while turning steering wheel. DO NOT hold wheel on stops. Add fluid if necessary. Attach coil lead. Install Rotunda Vacuum Tester (014-R1054) to power steering pump reservoir. Start engine.
4. Apply 20-25 in. Hg vacuum to reservoir for approximately 3 minutes with engine idling. As air is purged from system, vacuum will decrease. Maintain sufficient vacuum until fluid level stabilizes. Release vacuum. Check fluid level and fill as necessary.
5. Start engine. Turn steering wheel from stop to stop while checking for air in system. If condition is severe, repeat procedure until all air is removed. Lower and road test vehicle.

ADJUSTMENTS

Serpentine Belt

On vehicles with serpentine belts, belt tension is adjusted automatically.

Checking Belt Tension

Automatic belt tensioner has belt wear indicator marks located on top of tensioner housing. If tension indicator mark is not between wear indicator marks, belt is worn or incorrect belt is installed. When accessory drive belt is replaced or reinstalled after service procedure, belt may not sit properly in pulley grooves until engine runs for several minutes. On used belt reinstallation, recheck belt wear indicator marks after engine has been run for at least 5 minutes.

SECTOR SHAFT MESH LOAD

1. Deactivate driver-side air bag system. To deactivate air bag system, disconnect and shield negative battery cable. Disconnect positive battery cable. To avoid accidental air bag deployment, wait one minute before proceeding, allowing back-up power supply to deplete. Remove nuts securing air bag module. Install Rotunda Air Bag Simulator (105-R0010) to harness at top of steering wheel.
2. Mark pitman arm-to-sector shaft relation for installation reference. Disconnect pitman arm from sector shaft. Disconnect fluid return line at power steering reservoir and cap reservoir line. Place steering gear return line in clean container. Rotate steering wheel stop-to-stop several times to discharge fluid from steering gear.
3. If vehicle is equipped with tilt steering wheel, place wheel in center tilt position. Turn steering wheel to within 45 degrees of left stop. Using an INCH-lb. torque wrench on steering wheel nut, measure rotational drag required to turn gear about 1/4 turn from 45-degree position. Record reading.
4. Turn steering wheel to center position and measure torque required to rotate sector shaft back and forth across center position. Reading should be 5-9 INCH lbs. (.6-1.0 N.m) greater than torque reading obtained when turning away from 45 degrees from left stop.
5. If adjustment is necessary, loosen adjuster lock nut. (Scheme 3) Turn adjuster screw to adjust sector shaft mesh load. Tighten adjuster lock nut. Recheck rotational turning torque. Reconnect return line. Add fluid and reconnect pitman arm. Tighten pitman arm retaining nut to specification. See «TORQUE SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__torque-specifications).
6. Reactivate driver-side air bag. To reactivate air bag system, disconnect and shield negative battery terminal. Disconnect positive battery terminal. To avoid accidental air bag deployment, wait one minute before proceeding, allowing back-up power supply to deplete. Disconnect air bag simulator. Reconnect air bag connector. Install air bag module on steering wheel. Connect battery terminal. Turn ignition on. Air bag indicator light should illuminate for about 6 seconds, then go out. Wait one minute. If light does not illuminate again or illuminates and flashes, air bag system is functional.

Scheme 3

REMOVAL & INSTALLATION

Note. DO NOT weld, heat or bend steering linkage to repair or straighten components. When installing NEW cotter pins, tighten nut to lower specified torque, then tighten nut to next slot that aligns with stud hole. DO NOT hammer on ball studs. Ensure threads are clean and lubricated before tightening.

AIR SUSPENSION/EVO STEERING CONTROL MODULE

Note. Air suspension/EVO steering control module may also be referred to as simply control module.

1. Turn ignition and air suspension off. Air suspension switch in located in left side of trunk. Disconnect battery negative cable. Remove push pins retaining lower instrument panel insulator. Pull out lower instrument panel insulator. Disconnect courtesy light and power point. Remove lower insulator.
2. Remove glove box (if necessary). Remove control unit mounting screws. Disconnect harness connectors. Remove control module. To install, reverse removal procedure.

EVO ACTUATOR VALVE ASSEMBLY

Note. EVO actuator valve assembly may also be referred to as power steering control valve actuator.

Removal

1. Disconnect EVO wiring harness connector from EVO actuator valve assembly. Remove power steering pump. See «POWER STEERING PUMP»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__power-steering-pump).
2. Place pump in vise. Using 6-mm Allen wrench, remove EVO actuator valve assembly. (Scheme 4)

Installation

1. Install EVO actuator valve assembly into power steering pump. Tighten to specification. See «TORQUE SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__torque-specifications) .
2. To complete installation, reverse removal procedure. Refill and bleed hydraulic system. See «HYDRAULIC SYSTEM BLEEDING»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__hydraulic-system-bleeding) under LUBRICATION.

Scheme 4

Remove 2 screws and electrical connector to remove sensor. To replace sensor ring, steering column and shaft must be removed. See appropriate STEERING COLUMNS article.

Turn ignition and air suspension off. Air suspension switch in located in left side of trunk. Raise and support vehicle. Remove VSS retaining bolt. Remove VSS and driven gear from transmission. Disconnect electrical connector. Remove drive gear retainer and drive gear from VSS. To install, reverse removal procedure. Tighten VSS retaining bolt to 62-88 INCH lbs. (7-10 N.m). Ensure NEW "O" ring is properly seated in VSS housing.

1. Turn ignition and air suspension off. Air suspension switch in located in left side of trunk. Raise and support vehicle. Remove cotter pins and castle nuts. Using Tie Rod End Remover (T00L-3290-D), separate inner tie rod ends, idler arm and pitman arm from drag link. Remove drag link from vehicle.
2. To install, reverse removal procedure. Ensure idler arm stud seal is in place. Lower vehicle and adjust toe-in. See appropriate SPECIFICATIONS & PROCEDURES article in WHEEL ALIGNMENT. Tighten tie rod end clamp nuts to specification. See «TORQUE SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__torque-specifications) .

Turn air suspension off (if equipped). Raise and support vehicle. Using Tie Rod End Remover (T00L-3290-D), separate drag link from idler arm. Remove 2 idler arm mounting bolts. If idler arm support is disconnected from frame for other work, support idler arm with wire to prevent rotation (if equipped with threaded type bushing). To install, reverse removal procedure.

1. Turn ignition and air suspension off. Air suspension switch in located in left side of trunk. Raise and support vehicle. Mark pitman arm-to-steering shaft for installation reference. Remove drag link ball joint stud cotter pin and nut.
2. Using Tie Rod End Remover (T00L-3290-D), separate drag link from pitman arm. DO NOT hammer on end of puller. Remove pitman arm retaining nut. Using Pitman Arm Puller (T64P-3590-F), separate pitman arm from steering gear. To install, reverse removal procedure.

Disconnect EVO wiring harness connector from EVO actuator valve assembly. Drain power steering pump reservoir by disconnecting fluid return line at reservoir. DO NOT reuse fluid. Disconnect pressure hose at pump. DO NOT remove fitting from pump. Plug hoses to prevent contamination. Turn off air suspension switch (if equipped). Raise and support vehicle. Remove mounting bolts and pump. To install, reverse removal procedure. Check belt tension. Refill and bleed pump. See HYDRAULIC SYSTEM BLEEDING under LUBRICATION.

POWER STEERING PUMP PULLEY

Remove power steering pump. See POWER STEERING PUMP . Install Pulley Remover (T69L-10300-B) on pulley hub. Remove pulley. Install power steering pump pulley using Pulley Installer (T91P-3A733-A). Install pulley flush with shaft. To complete installation, reverse removal procedure.

Disconnect inlet and return hoses. Drain reservoir. Remove 2 retaining nuts and remove reservoir tank. To install, reverse removal procedure.

1. Remove stone shield. Disconnect hydraulic lines from steering gear and mark for installation reference. Plug lines and ports to prevent contamination.
2. Remove flexible coupling bolts. Turn ignition and air suspension off. Air suspension switch in located in left side of trunk. Raise and support vehicle. Remove sector shaft nut and lock washer. Discard lock washer. Mark pitman arm and sector shaft for installation reference. Using Puller (T64P-3590-F), remove pitman arm.
3. Support steering gear and remove gear attaching bolts. Remove flexible coupling clamp bolts. Separate steering gear from coupling and remove from vehicle.

1. Turn steering wheel to straight-ahead position. Center steering gear input shaft with centerline of indexing flats facing 4 o'clock. Slide steering gear input shaft into flex coupling and into place on frame side rail. Install and tighten attaching bolts.
2. Ensure wheels are in straight-ahead position and install pitman arm, NEW lock washer and nut onto sector shaft. Tighten nut to specification. See «TORQUE SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__torque-specifications) . Move flex coupling into place on steering gear input shaft and install attaching bolt.
3. Install and tighten pressure and return lines to steering gear. Fill reservoir and bleed system. See «HYDRAULIC SYSTEM BLEEDING»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__hydraulic-system-bleeding) under LUBRICATION. Reinstall stone shield.

Turn ignition and air suspension off. Air suspension switch in located in left side of trunk. Raise and support vehicle. Loosen adjusting sleeve clamp bolts. Remove cotter pins and castle nuts from tie rod ends. Using Tie Rod End Remover (T00L-3290-D), remove tie rod ends from steering knuckles. Unscrew tie rod ends from adjusting sleeves, noting number of turns necessary for installation reference.

1. Apply penetrating oil to clamps, tie rod threads and adjusting sleeves. Wipe threads clean. Lubricate threads with chassis lube. Install adjusting sleeve clamps. Thread tie rod ends same number of turns required during removal.
2. Ensure both ends are equal distance (within 3 threads) into sleeve. Install castle nuts, using NEW cotter pins. Properly position adjusting sleeve clamps. Lower vehicle and adjust toe-in. See appropriate SPECIFICATIONS & PROCEDURES article in WHEEL ALIGNMENT. Tighten tie rod end clamp nuts to specification. See «TORQUE SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__torque-specifications) .

POWER STEERING PUMP

Manufacturer does not recommended disassembly and repair. EVO actuator is only component of pump assembly separately serviced. Should further service be required, replace pump assembly.

Scheme 5

1. Drain steering gear, and mount in holding fixture. Remove lock nut and washer from adjusting screw. Turn input shaft to either stop. Turn input shaft back 1 5/8 turns to center gear. Centerline of flats on pinion spline should face 4 o'clock position.
2. Remove sector shaft cover bolts. Tap lower end of sector shaft with a soft hammer. Lift cover and shaft from housing as an assembly. Discard "O" ring.
3. Turn sector shaft cover counterclockwise to remove cover from adjusting screw. Remove valve housing attaching bolts and identification tag. Lift control valve housing from steering gear housing, while holding piston to prevent it from rotating off worm shaft.
4. Remove and discard control valve housing-to-gear "O" rings. Hold piston and ball bearing nut assembly so ball bearing guides face upward. Remove ball guide clamp screws and clamp.
5. Place finger over opening in ball bearing guide, and turn piston so ball bearing guide is over a clean container. Allow guide tubes to drop into container. Rotate input shaft from stop to stop until 28 balls fall into container.
6. Remove valve assembly from piston. Ensure all ball bearings have been removed. Install valve assembly in holding fixture. Loosen Allen head set screw at control valve housing.
7. Using Adjuster/Lock Nut Wrench (T66P-3553-B) and Spacer Valve Housing-to-Piston Holder (T66P-3553-C), remove worm bearing race lock nut. (Scheme 5) Carefully slide input shaft, worm and valve assembly out of valve housing. Slightest cocking of spool may cause it to jam in housing and damage sleeve.
8. Remove snap ring from lower end of housing. Using Puller (T58L-101-B), remove and discard dust seal. Remove and discard pressure seal in same manner.
9. Using puller, remove and discard dust seal from rear of valve housing. Carefully insert Seal Remover/Installer (T65P-3524-A2) in valve body assembly opposite oil seal. Gently tap bearing and seal out of housing, and discard seal.
10. If valve bore is damaged, remove inlet and outlet tube seats with Brass Tube Seat Remover (T74P-3504-L). Remove Teflon rings only if scratched or worn. Insert a knife blade under rings and cut them off. DO NOT scratch valve sleeve. Remove plastic ring and "O" ring from piston and ball bearing nut.

Scheme 6

1. Install Mandrel (T75L-3517-A1) over rotary valve sleeve. Slide one Teflon ring over mandrel. Slide Pusher (T75L-3517-A2) over mandrel. Rapidly push down on pusher, forcing Teflon ring down ramp and into fourth groove of rotary valve sleeve.
2. Repeat procedure 3 more times, adding Spacer (T75L-3517-A3) under mandrel each time. After installing 4 Teflon rings, apply gear lubricant to rotary valve sleeve and Teflon rings. Install one spacer over input shaft as a pilot for installing sizing tube.
3. Slowly install Sizing Tube (T75L-3517-A4) over rotary valve sleeve valve end of worm shaft onto Teflon rings. Ensure rings are not bent. Sizing tube must be able to slide over rings. Remove sizing tube and check condition of Teflon rings. Teflon rings must turn freely in grooves.
4. Coat NEW tube seats with petroleum jelly. Install tube seats using Brass Tube Seat Installer (T74P-3504-M). Coat bearing and seal surface of housing with petroleum jelly. Position bearing into control valve housing. Press bearing with metal-covered side facing outward. Ensure bearing rotates freely.
5. Dip NEW oil seal in Mercon ATF. Place seal into housing, metal side out. Drive seal into housing until outer edge does not quite clear snap ring groove. Place snap ring into housing. Drive snap ring in until seated in groove.
6. With rubber side out, drive dust seal in position behind groove in input shaft. Lubricate seals and sector shaft bore. Place dust seal onto Shaft Seal Installer (T77L-3576-A) so raised lip of seal is toward tool.
7. Slide pressure seal onto tool with flat of pressure seal against flat of dust seal. Carefully insert seals into sector shaft bore with tool until they clear snap ring groove. DO NOT bottom seals against bearing. Install snap ring.
8. Dip NEW "O" ring in Mercon ATF. Install "O" ring on piston and ball nut. Install a NEW plastic ring on piston and ball nut. DO NOT stretch plastic ring any more than necessary. Mount valve housing in holding fixture (flanged end up).
9. Lubricate valve sleeve rings. Install worm and valve in gear housing. Using Adjuster/Lock Nut Wrench (T66P-3553-B) and Spacer Valve Housing-to-Piston Holder (T66P-3553-C), install and tighten race nut to specification. See «TORQUE SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__torque-specifications). (Scheme 5)
10. Install Allen head set screw through control valve housing. Tighten set screw to specification. See «TORQUE SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__torque-specifications). Place piston on bench, with ball bearing guide holes facing up. Insert worm shaft so first groove is aligned with hole nearest center of piston.
11. Place ball guide into piston. While turning worm shaft clockwise, as viewed from input end of shaft, place at least 27 ball bearings into ball bearing guide. (Scheme 6) If all ball bearings have not been fed into guide upon reaching right stop, rotate input shaft back and forth while installing remaining ball bearings.
12. Secure guides in ball bearing nut with clamp, and tighten screws to specification. See «TORQUE SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__torque-specifications). (Scheme 6) Apply petroleum jelly to seal on piston. Place NEW "O" ring on valve housing. Slide piston and valve into gear housing. Align oil passage in valve housing with passage in gear housing.
13. Position NEW "O" ring into gear housing oil passage. Install, but DO NOT tighten, identification tag and attaching bolts. Rotate ball nut so teeth are parallel with sector teeth. Tighten valve housing bolts to specification. Install sector shaft cover "O" ring in gear housing. Turn input shaft to center piston.
14. Apply petroleum jelly to sector shaft journal. Position sector shaft and cover assembly in gear housing. Rotate input shaft one turn on either side of center. Install and tighten cover bolts to specification. See «TORQUE SPECIFICATIONS»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__torque-specifications). Adjust sector shaft. See «SECTOR SHAFT MESH LOAD»(/lincoln/town-car/iii-1997-2003/remont/electronic-steering/#electronic-steering-system__sector-shaft-mesh-load) under ADJUSTMENTS.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS (PUMP)

TORQUE SPECIFICATIONS (STEERING GEAR)

EVO Power Steering Wiring Diagram (2000-01 Town Car). Scheme 7

See also:
• POWER STEERING PUMP FLOW TEST SPECIFICATIONS
• RELIEF PRESSURE TEST
• TEST F
• A
• B
• C
• D
• E
• CONNECTOR IDENTIFICATION.
• AIR SUSPENSION/EVO STEERING CONTROL MODULE
• EVO ACTUATOR VALVE ASSEMBLY
• TORQUE SPECIFICATIONS
• POWER STEERING PUMP
• HYDRAULIC SYSTEM BLEEDING
• SECTOR SHAFT MESH LOAD