Electrical testing Audi A8 D2 рестайлинг

Electrical testing

1. For vehicles for which the self - diagnosis does not give any indication of the source of the malfunction the complete electrical check must be worked through.
2. In vehicles in which the self- diagnosis provides a direct indication of the source of the malfunction only perform the test steps recommended in the DTC table (specific testing).

1. An "Automatic test sequence" must first be performed to establish that any DTCs present in the transmission and Engine Control Module (ECM)s can only originate from the ABS. Connect up Scan tool V.A.G 1551 and select address word 00 with ignition switched on. See «VAG1551 SCAN TOOL (ST), CONNECTING AND ENTERING ADDRESS WORD»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr__vag1551-scan-tool-st-connecting-and) . After completing the "Electrical check", check and erase the DTC memories of the transmission and Engine Control Module (ECM)s.
2. Make sure multiple connector between wiring harness and ABS Control Module (w/EDL) -J104- is in perfect condition, i.e. not bent, broken or corroded terminals. Replace any damaged terminals using wiring repair kit VAS 1978.

Note. The instructions supplied with wiring repair kit VAS 1978 normally do not permit repairs to the wiring of the ABS and its associated systems. However, this only applies to the screened wiring in the systems.

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1. Switch ignition and electrical devices off before beginning the check (headlights, lighting, fan, etc.).
2. For test steps 13 to 16 the vehicle must be raised so that the wheels can turn freely. On vehicles with manual transmission put the shift lever in neutral. On vehicles with automatic transmission move the selector lever to position "N".

The following equipment is required

1. VAG 1598/20 Test box
2. VAG 1594 Adapter cable set
3. VAG 1526 Hand-held multimeter
4. VAG 1310 A Pressure gauge

Connecting test box VAG 1598/20 and checking ABS/EDL and ASR systems.

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1. Switch ignition off.
2. Remove ABS Control Module (w/EDL) -J104- See «ABS CONTROL MODULE (W/EDL) -J104-, REMOVING AND INSTALLING»(/audi/a8/d2-1999-2002/remont/anti-locktraction-control/#antilock-brake-system) .
3. Disconnect the multi-pin connector from ABS Control Module (w/EDL) -J104-.
4. Check multi-pin connector between wiring harness and ABS Control Module (w/EDL) -J104-. Socket designations of test box VAG 1598/20 are identical with terminal designations on ABS Control Module (w/EDL) -J104- as well as those on wiring harness connector. See appropriate System Wiring Diagrams article.
5. Connect test box VAG 1598/20 to multi-pin connector on ABS harness.

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1. The terminal descriptions of test box VAG 1598 are identical to the terminal descriptions of ABS Control Module (w/EDL) -J104- in the wiring diagram. Incorrect test procedures can cause system damage. Do not make connections between any terminals other than those listed in the test table. See appropriate System Wiring Diagrams article.
2. The specified values refer to the readings obtained on tester VAG 1526 and are not necessarily applicable to other test units.
3. If the readings obtained do not match the specified values, carry out the DTC correction measures in the right-hand part of the table. See appropriate System Wiring Diagrams article.
4. If the specified values are achieved, also check wiring for loose connections and short circuit to positive and Ground (GND). This applies especially to sporadic DTCs.
5. Use test leads VAG 1594 for checking continuity (bridging leads).
6. If the measured figures only differ slightly from the specified values, clean the terminals of the testers and test leads (with terminal spray G 000 700 04) and repeat the check. Before replacing components, check wiring and connections again. This is particularly important if the specification calls for a resistance reading of less than 10 ohm.. The output connections on ABS Control Module (w/EDL) -J104- are wired differently for the various different versions. 1) FWD with Bosch ABS/EDL 5 only 2) FWD with Bosch ABS/ASR 5 only 3) 4WD with Bosch ABS/EDL 5 only (pressure-side control) 4) 4WD with Bosch ABS/EDL 5 only (suction-side control) For the DTC Table, see «DTC TABLE»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr__dtc-table) . For brake bleeding instructions, see «BLEEDING BRAKE SYSTEM»(/audi/a8/d2-1999-2002/remont/mechanical-hydraulic/#disc-brakes) . For ABS Hydraulic Unit info, see «ANTILOCK BRAKE SYSTEM»(/audi/a8/d2-1999-2002/remont/anti-locktraction-control/#antilock-brake-system) . For instrument cluster information, see «INSTRUMENTS»(ref-196896) (1997-99), or «INSTRUMENTS»(/audi/a8/d2-1999-2002/remont/gauges-instrument-panels/#instruments) (2000-03). For speed sensor circuit information, see «ANTILOCK BRAKE SYSTEM»(/audi/a8/d2-1999-2002/remont/anti-locktraction-control/#antilock-brake-system) . For instrument cluster information, see «INSTRUMENTS»(ref-196896) (1997-99), or «INSTRUMENTS»(/audi/a8/d2-1999-2002/remont/gauges-instrument-panels/#instruments) (2000-03). For information about connecting V.A.G. 1551, see «VAG1551 SCAN TOOL (ST), CONNECTING AND ENTERING ADDRESS WORD»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr__vag1551-scan-tool-st-connecting-and) . To check DTC memory, see «CHECK DTC MEMORY»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr__check-dtc-memory) . To erase DTC memory, see «ERASE DTC MEMORY»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) . For instrument cluster information, see «INSTRUMENTS»(ref-196896) (1997-99), or «INSTRUMENTS»(/audi/a8/d2-1999-2002/remont/gauges-instrument-panels/#instruments) (2000-03).

Information in this section applies to ABS/EDL Bosch 5.3 for AWD vehicles from MY 1997 and for ABS/EDL/ASR Bosch 5.3 for FWD vehicles from MY 1998.

Bosch ABS/EDL 5.3 was introduced for the Audi A8 from MY 1997 on AWD vehicles. The new version supersedes the Bosch type 5.0.

Bosch ABS/EDL/ASR 5.3 was introduced for the Audi A8 from MY 1998 as an optional extra on FWD vehicles. The new version supersedes the Bosch type 5.0.

The Bosch type 5.3 system has a more compact design. The ABS Return Flow Pump -V39-, the ABS Hydraulic Unit -N55- and the ABS Control Module (w/EDL) -J104- are combined to form the Hydraulic Control Module -N174-. The bolts that connect the individual components of the ABS Hydraulic Unit must not be loosened.

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1. The ABS/EDL systems and the ASR are system that affect the safety of the vehicle. Work on these systems must only be carried out by qualified personnel.
2. When the ignition is on and the On Board Diagnostic (OBD) detects a malfunction in the system, the ABS Warning Light -K47-, the Traction Control Indicator Light -K86- and the red brake warning light come on. The warning lights are located in the instrument cluster. The red brake warning light is incorporated in the display of the driver information system. The warning lights for ABS/EDL and ASR are located underneath the display. For further information refer to "Warning light functions". See «TABLE OF WARNING LIGHT FUNCTIONS»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) .
3. If the brake system is not fully functional, but the ABS Warning Light -K47- and the red brake warning light do not light up, this means the malfunction must be sought in the conventional braking system (mechanical/hydraulic components). See «DISC»(/audi/a8/d2-1999-2002/remont/mechanical-hydraulic/#disc-brakes) .

1. Certain DTCs are only detected by the On Board Diagnostic (OBD) when the vehicle is moving. The system can be tested by carrying out a test drive. Maintain a speed above 60 km/h for a period of 30 seconds. Observe the traffic conditions and perform a braking controlled by the ABS. The control can be felt by a pulsing sensation at the brake pedal. WARNING: If the vehicle is driven after a malfunction has been detected there is danger of an accident! The function of the brake system will be impaired. As the brake pressure is no longer controlled by the electronic brake force distribution the rear wheels tend to break excessively. Due to this the tail of the vehicle may break away unexpectedly. If test and measuring instruments are required during a test drive, these must always be secured to the rear seat and operated by a second person from this position. If test equipment were operated from the front passenger seat, the person sitting there could be injured if the front passenger airbag were triggered in the event of an accident. If there is a complaint a pin-pointed troubleshooting must be carried out: First switch on the ignition and observe lighting up of the warning lights. The «TABLE OF WARNING LIGHT FUNCTIONS»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) enables an initial determination. Determine test preconditions. See «TEST REQUIREMENTS»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) . Connect Scan tool V.A.G 1551 and select "Brake electronics" with address word 03. See «VAG1551 SCAN TOOL (ST), CONNECTING AND ENTERING ADDRESS WORD»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr__vag1551-scan-tool-st-connecting-and) . Check control module version. See «CHECK CONTROL MODULE VERSION»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) and press --> button. Check DTC memory. See «CHECK DTC MEMORY»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) . If a DTC is stored: Make a note of the DTC and erase DTC memory. See «ERASE DTC MEMORY»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) . Complete data transfer with the function "End output". See «END OUTPUT»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr__end-output) . Repair malfunction according to DTC table, see «CHECK DTC MEMORY»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) . Reselect "Brake Electronics" with address word 03. Check and erase DTC memory. Complete data transfer with the function "End output". Disconnect Scan tool V.A.G 1551. Make sure that all connectors are connected tightly and correctly. Perform test drive. See «ROAD TEST»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) . The warning lights must not light up during the test drive. If the warning lights light up during the test drive the troubleshooting must be carried out again. NOTE: If the connector is disconnected from the control module during the road test, there is danger of a false DTC entry into the DTC memory of another control module. The mechanical and hydraulic functions of the brake system remain effective. However, due to the failure of the ABS/EDL system, the brake pressure regulator will also no longer work, which could endanger the safety of the vehicle when driving.
2. Switch off the ignition before removing and installing components. If the vehicle is equipped with a coded radio, obtain the security code before disconnecting the grounding strap of the battery.
3. If a component is indicated as being faulty, only replace it if you are sure that the electrical wiring for that component is in proper condition. The wiring must be able to transmit the necessary signals without interference or resistance. Check the wiring for: Corrosion and loose connections in the connectors and Ground (GND) connections. If any of the connector terminals are bent, broken or corroded, use the wiring repair kit VAS 1978 to install new terminals. Open circuits Short circuits to Ground (GND) or to positive NOTE: The instructions supplied with wiring repair kit VAS 1978 normally do not permit repairs to the wiring of the ABS and its associated systems. However, this only applies to the screened wiring in the systems.
4. If the hydraulic control module has to be replaced make sure the correct version is installed. Check control module version first. This appears on the display of the Scan tool V.A.G 1551 once communications have been established between control module and Scan tool, or it can be called up by selecting function 01 "Checking control module version". See «CHECK CONTROL MODULE VERSION»(/audi/a8/d2-1999-2002/remont/warning-system/#on-board-diagnostic-obd-absedlasr) . It is also possible to identify the equipment installed on the vehicle from a combination of letters on the vehicle data sticker. The sticker is located in the spare wheel well. 1AC: Anti-lock brake system 1AH: Anti-lock brake system with electronic differential lock 1AJ: Anti-lock brake system with electronic differential lock and traction control system (ASR) 1AT: Anti-lock brake system with electronic differential lock, traction control system (ASR) and electronic stability program (ESP)
5. Absolute cleanliness is required when working on the hydraulic control module. Carefully clean the hydraulic connections and adjacent parts. Never use aggressive cleaning agents such as brake cleaner, gasoline, thinner or products containing mineral oil, e.g. oils and greases. Do not disconnect hydraulic lines before they have been cleaned.
6. Observe the relevant information when handling brake fluid. See «BLEEDING BRAKE SYSTEM»(/audi/a8/d2-1999-2002/remont/mechanical-hydraulic/#disc-brakes) .
7. Place removed parts on a clean surface and cover. Only use lint-free cloths.
8. Only use genuine wrapped parts. Only remove them from their packaging immediately prior to installation.
9. Bleed the brake system if connections in the system have to be opened. See «BLEEDING BRAKE SYSTEM»(/audi/a8/d2-1999-2002/remont/mechanical-hydraulic/#disc-brakes) .

1. Permissible and identical wheels and tire size Correct tire pressure at all wheels.
2. Mechanical and hydraulic parts of the brake system must be in order: Hydraulic connections and lines are not leaking (visual check of ABS Hydraulic Unit, brake callipers, wheel brake cylinder, tandem brake master cylinder).
3. Wheel bearings and wheel bearing play OK. See «SUSPENSION - FRONT»(/audi/a8/d2-1999-2002/remont/suspension-front/#suspension-front) . See «SUSPENSION - REAR»(/audi/a8/d2-1999-2002/remont/suspension-rear/#suspension-rear) .
4. Wheel speed sensors must be installed correctly. See «ANTILOCK BRAKE SYSTEM»(/audi/a8/d2-1999-2002/remont/anti-locktraction-control/#antilock-brake-system) .
5. Supply voltage OK (at least 10.0 V).
6. Connector properly attached to ABS Control Module (w/EDL) -J104-, catch engaged.
7. The diagnosis procedure can only be started with the vehicle stationary and the ignition switched on (or with engine running). The diagnosis cannot be started if wheel speed exceeds 2.75 km/h. Diagnosis is terminated if speed exceeds 20 km/h.
8. While testing the ABS, ABS/EDL and ASR systems, ensure that the vehicle's electronics are not subjected to electromagnetic interference: keep the vehicle away from equipment with a high current draw such as electric welding units.