Diagnosis & Service - 01v Audi A4 B5

APPLICATION & LABOR TIMES

APPLICATION & LABOR TIMES

IDENTIFICATION

Volkswagen Audi Group (VAG) transaxle type is cast into transaxle case above left output shaft flange. Transaxle code and build date are located on front top of transaxle case. (Scheme 1)

DESCRIPTION & OPERATION

Transaxle includes a 5-speed automatic transmission, a torque converter with clutch, a final drive and solenoid-operated valve body. Under normal conditions, all shifts are controlled by a Transaxle Control Unit (TCU), 4th and 5th gears are overdrive gears.

Note. TCU may be referred to as Transmission Control Module (TCM).

The electronic control consists of a TCU (attached to the brake pedal bracket), control solenoids, various sensors and switches. The control solenoids direct oil pressure inside the valve body.

The TCU monitors input and output signals. If electrical problems occur, TCU will record faults in TCU memory and may go into fail-safe mode. The TCU memory can only be read on VAG Tester (1551).

The TCU also controls shift-lock system. This system locks the gear selector in Park or Neutral unless the brake pedal is pushed down. The TCU uses a shift-lock control relay to release a gear-selector mounted solenoid.

Scheme 1

LUBRICATION & ADJUSTMENTS

Note. See appropriate AUTOMATIC article in TRANSMISSION SERVICING.

DRIVE AXLE SHAFTS

See appropriate AXLE SHAFTS article in AXLE SHAFTS.

OIL COOLER FLUSHING

1. Remove oil lines and allow fluid to drain. Using pressurized solvent, flush remaining fluid and debris from oil lines and cooler. Repeat flushing if necessary.
2. Use pressurized shop air to remove solvent from oil lines and oil cooler. Install a new external oil filter.

MECHANICAL & ELECTRICAL CHECKS

If gear selector is stuck in Park or Neutral, go to SHIFT LOCK SYSTEM . If gear positions are missing, shift quality is poor or no shifts are possible, ensure all electrical connections are okay and fluid level is correct. Check for Diagnostic Trouble Codes (DTCs).

FAIL-SAFE FUNCTION

When one or more components or sensors fail, the TCU will substitute functions and continue to operate. If a critical component fails, and the TCU is active, transmission will shift into 4th gear with torque converter clutch disengaged and entire gear display will light. Reverse can be engaged and selector lock will not work. If a critical component fails, and the TCU is inactive, symptoms will be the same, but OBD codes cannot be accessed.

Operation

A mechanical control cable prevents ignition key from being removed unless gear selector is in Park. With ignition key removed, gear selector locks in Park. (Scheme 2)

Note. If battery is disconnected or discharged, gear selector can be moved out of Park by turning ignition key to START position.

All models are equipped with an electronic shift lock system. TCU controls shift lock system. This system locks gear selector in Park or Neutral position unless brake pedal is pushed down. TCU uses shift lock control relay to release a solenoid mounted on gear selector assembly.

Note. Shift lock relay will not lock gear selector when vehicle speed is greater than 3 MPH.

Scheme 2

Functional Check

1. With ignition key removed, ensure gear selector cannot be moved from Park. Insert key in ignition switch.
2. Turn ignition on. Ensure gear selector can only be moved with brake pedal pressed down. Move gear selector to Neutral position.
3. Without pressing brake pedal, ensure gear selector cannot move out of Neutral. Press brake pedal down. Ensure it is now possible to move gear selector.
4. If shift lock system does not operate as described, check electrical system of shift lock system with VAG Tester (1551). If Tester is not available, see testing information under «ELECTRONIC SELF-DIAGNOSTICS»(/audi/a4/b5-1994-1999/remont/automatic-trans/#diagnosis-service-01v__electronic-self-diagnostics). (Scheme 6)- (Scheme 10).
5. If any problems are found, service harness or components. If shift lock system still does not operate correctly, check for worn or damaged parts and replace as necessary. (Scheme 3) If no problems are found, TCU may be defective.

Scheme 3

Note. Perform the following adjustments in order given.

Adjustment (Control Cable)

1. Remove cable housing mounting screws at gear selector console. Loosen lock screw.
2. Move gear selector to Drive position. Turn ignition on. Move control cable until a .060" (1.5 mm) feeler gauge fits between lock flap and lock pin.
3. Turn ignition off. Turn ignition on. Ensure gap is still .060" (1.5 mm). Turn ignition off and on several times and recheck gap. Install cable housing to gear selector console.

Removal & Installation (Control Cable)

1. Remove center console cover. Disconnect negative battery cable and wait 30 seconds. Disconnect voltage supply connector for air bag.
2. Using Torx wrench, remove air bag retaining screws from rear side of steering wheel. Remove air bag. Remove steering wheel. Remove dash panel.
3. Place gear selector in Neutral position. Remove cable housing mounting screws at gear selector console.
4. Remove cover from top of ignition switch. Remove spring clip holding cable housing to ignition assembly. Lift and tilt cable housing upward. Rotate control cable 1/4 turn until control cable unhooks from ignition switch. (Scheme 4) NOTE: DO NOT kink control cable. If control cable is kinked, gear selector may not move.
5. Remove clip holding cable housing to A/C-heater housing. Remove cable housing from vehicle. To install cable housing, reverse removal procedure. Adjust control cable. See «ADJUSTMENT (CONTROL CABLE)»(/audi/a4/b5-1994-1999/remont/automatic-trans/#diagnosis-service-01v__adjustment-control-cable) procedure.

Scheme 4

ELECTRONIC SELF-DIAGNOSTICS

1. Electronic control consists of TCU (attached to brake pedal bracket), control solenoids, and various sensors and switches. TCU monitors input and output signals.
2. If TCU detects problems in transaxle-related circuits or devices, TCU may record a trouble code in memory. To obtain trouble codes, use VAG Tester (1551). (Scheme 5) All trouble code and related testing information is contained in tester. See «DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS»(/audi/a4/b5-1994-1999/remont/automatic-trans/#diagnosis-service-01v) table.
3. If tester is not available, turn ignition off. Disconnect TCU harness connector. Install Back-Probe Harness (VAG 1598) and 88-Pin Adapter (1598/20) between TCU and TCU harness. Measure voltage and resistance between specified terminals of TCU connector. (Scheme 6)- (Scheme 10).
4. If problem is found, service harness or component(s). If no problem is found, TCU may be defective. All testing should be done with components at ambient temperature. All resistance testing is done with Back-Probe Harness (VAG 1598) disconnected. All voltage testing is done with Back-Probe Harness (VAG 1598) connected.

DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

REMOVAL & INSTALLATION

See appropriate REMOVAL & INSTALLATION article in AUTOMATIC TRANSMISSIONS.

TORQUE CONVERTER

Remove torque converter. Check torque converter for any wear or damage, and replace if necessary. If torque converter is being reused, drain old fluid. Tilt converter on bench and siphon out all fluid.

COMPONENT DISASSEMBLY & REASSEMBLY

Information is not available from manufacturer at time of publication.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Transaxle Wiring Diagram. Scheme 11

See also:
• SHIFT LOCK SYSTEM
• ELECTRONIC SELF-DIAGNOSTICS
• ADJUSTMENT (CONTROL CABLE)