On Board Diagnostic ( OBD) - 3.7l & 4.2l v8 (aew, Abz) Audi A8 D2

Function

The Multiport Fuel Injection (MFI) system is equipped with an Engine Control Module (ECM) with On Board Diagnostic (OBD) capability.

When malfunctions occur in sensors or components monitored by OBD, Diagnostic Trouble Codes (DTC) are stored in DTC memory.

Stored DTCs are identified using the VAG1551 Scan Tool (ST). See CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02) .

After the necessary repairs are completed, DTC memory must be erased. See ERASE DTC MEMORY, (SCAN TOOL FUNCTION 05) .

OBD II legal regulations require a display (readiness code) that shows inspection readiness for the annual exhaust emissions test. The readiness code shows that every component and/or system that affects exhaust emissions, which can lead to the Malfunction Indicator Lamp (MIL) being switched on, has been operated at least once with positive results.

The readiness code is reset and/or erased every time DTC memory is erased, the ECM harness connector is disconnected from the ECM -J220- (example: when connecting test box VAG1598/19), or the battery has been disconnected. See READINESS CODE, GENERATING .

Available functions

AVAILABLE FUNCTIONS

Malfunction Indicator Lamp (MIL), function

If a malfunction is recognized by the Engine Control Module (ECM) or the Transmission Control Module (TCM), this is indicated by the MIL coming on.

Location of MIL

Locating Malfunction Indicator Lamp (MIL). Scheme 1

Note. When a recognized malfunction switches on the MIL, it will either blink or light continuously. In either case, DTC memory for the ECM and the TCM must be checked. See CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02) . If the MIL starts to blink, there is a malfunction that can lead to damage of the Three Way Catalytic Converter (TWC). In this case, driving should only continue using reduced power until the MIL goes out or stays on continuously. The malfunction must be rectified as quickly as possible. If the MIL lights continuously, there is a malfunction that affects exhaust emissions. In this case, DTC memory for the ECM and the TCM must be checked, and the malfunction must be rectified as quickly as possible. Some malfunctions may occur without causing the MIL to come on. When driveability or performance problems are reported, and there is no indication from the MIL, the operation of the MIL must be checked. In addition, DTC memory for the ECM and TCM must be checked, as there may be malfunctions stored that do not switch the MIL on immediately.

Functional testing

1. Switch ignition on. The MIL must light up.

If the MIL does not light

1. Check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
2. Check wiring to MIL using appropriate wiring diagram.

Requirements

1. Battery Positive Voltage (B+) OK
2. Fuses for engine electronics OK
3. Fuel pump relay OK

Scheme 2

1. Connect VAG1551 or VAG1552 scan tool to 16-pin Data Link Connector (DLC) to left of steering column, using adapter cable VAG 1551/3. (Scheme 2): Connecting VAG1551 Scan Tool To 16-Pin Data Link Connector (DLC)

Indicated on display

Operating modes 1 and 2 are displayed alternately

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (1 Of 10). Scheme 3

Note. If there is no display, check voltage supply for DLC. Additional operating instructions can be obtained by pressing the VAG1551 scan tool HELP button. The--> button is used to advance to the next step in the program sequence.

1. Switch ignition on.
2. Switch printer on by pressing PRINT button (indicator light in button lights up).
3. Press button -1- to select "Rapid data transfer" operating mode 1.

Indicated on display

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (2 Of 10). Scheme 4

Note. After inserting address word 00 and pressing the -Q- button, an automatic test sequence is carried out (checks DTC memory for all systems with rapid data transfer capability).

1. Press buttons -0- and -1- to insert "Engine Electronics" address word 01.

Indicated on display

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (3 Of 10). Scheme 5

1. Press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (4 Of 10). Scheme 6

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (5 Of 10). Scheme 7

If the following is indicated on the display

1. Press the HELP button to print a list of possible causes.

Note. Check wiring and connections between the DLC and the ECM. Engine control module faulty: see DIAGNOSTIC TROUBLE CODE (DTC) TABLE .

If the following is indicated on the display

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (6 Of 10). Scheme 8

Note. On a vehicle with several On Board Diagnostic (OBD) systems, check wiring and connections between the individual systems.

If one of the following 2 problems is indicated on the display

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (7 Of 10). Scheme 9

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (8 Of 10). Scheme 10

Note. Check wiring and connections between the DLC and the ECM.

1. After the malfunction cause has been repaired, insert address word 01 again, and press -Q- button to confirm input.

Indicated on display (ECM identification and coding; example shown)

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (9 Of 10). Scheme 11

ECM IDENTIFICATION AND CODING (EXAMPLE)

Note. If the ECM version that corresponds to the vehicle is not displayed, replace ECM. Incorrect ECM coding leads to: Performance problems (for example, jerky shifting, abrupt load changes, etc.) Increased fuel consumption Elevated exhaust gas values Reduction in transmission service life Malfunctions not present are stored in DTC memory Necessary functions are not carried out (oxygen sensor control, actuation of EVAP canister system, etc.)

1. Advance program sequence by pressing --> button.

Indicated on display

V.A.G 1551 Scan Tool Display - Connecting VAG1551 Scan Tool (10 Of 10). Scheme 12

Note. After pressing the HELP button, an overview of the possible functions is printed out.

Check Diagnostic Trouble Code (DTC) Memory, (scan tool function 02)

Note. If DTC memory has been erased, generate a new readiness code. See READINESS CODE, GENERATING . If DTC memory has not been checked, do not erase DTC memory as it will be necessary to generate a new readiness code.

1. Connect VAG1551 or VAG 1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (engine idling). See «VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .

If engine does not start

1. Crank engine for approx. 6 seconds. Ignition must not be switched off.
2. Switch printer on by pressing PRINT button (indicator light in button lights up).

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Diagnostic Trouble Code (DTC) Memory (1 Of 3). Scheme 13

Scheme 14

1. Press buttons -0- and -2- to select "Check DTC Memory" (scan tool function 02), and press -Q- button to confirm input. Indicated on display (number of stored diagnostic trouble codes, or "No DTC recognized") (Scheme 14): V.A.G 1551 Scan Tool Display - Checking Diagnostic Trouble Code (DTC) Memory (2 Of 3) NOTE: If the printer is switched on, the stored malfunctions will be displayed and printed out in sequence.

Indicated on display

If no DTCs are recognized

V.A.G 1551 Scan Tool Display - Checking Diagnostic Trouble Code (DTC) Memory (3 Of 3). Scheme 15

1. Advance program sequence by pressing--> button.
2. Press buttons -0- and -6- to select "End Output" (scan toolfunction 06) and press -Q- button to confirm input.
3. Repair malfunctions printed out according to «DIAGNOSTIC TROUBLE CODE (DTC) TABLE»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__diagnostic-trouble-code-dtc-table) .
4. Erase DTC memory. See «ERASE DTC MEMORY, (SCAN TOOL FUNCTION 05)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .
5. Generate readiness code. See «READINESS CODE, GENERATING»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .

Diagnostic Trouble Code (DTC) table

1. The DTC table is organized according to SAE and VAG trouble codes.
2. The column labeled "MIL" specifies the switching conditions that cause the MIL to be illuminated. (Dcy = Driving cycle).
3. When necessary repairs have been completed, erase DTC memory ( «ERASE DTC MEMORY, (SCAN TOOL FUNCTION 05)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) ) and generate new readiness code ( «READINESS CODE, GENERATING»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) ).
4. DTCs that are recognized as a result of intermittent malfunctions, or DTCs that are not erased after repairs, are classified as sporadic malfunctions. These are identified by the designation "SP" appearing in the display.
5. A sporadic malfunction will be erased if it no longer occurs after 40 driving cycles during which the engine reaching operating temperature.
6. Not all malfunctions cause the MIL to come on. In some cases, two consecutive driving cycles (Dcy) are necessary.
7. If the MIL comes on while the engine is running, a malfunction that affects exhaust emissions has been recognized, and at least one DTC has been stored in DTC memory. In this case, DTC memory for both the ECM and the TCM must be checked.
8. If the MIL blinks, there is a malfunction that can lead to damage of the three way catalytic converter (for example, combustion misfiring with high misfiring rate). In this case, driving should only continue using reduced power (until the MIL goes out or comes on continuously) and the cause of the malfunction should be eliminated as quickly as possible.
9. If a faulty component is determined to be the cause of the malfunction, always check the wiring to the component first for short or open circuit using the applicable wiring diagram.
10. Before replacing a faulty component, also inspect wiring and wiring connections to the component, as well as Ground connections, using the applicable wiring diagram. This is especially important when malfunctions have been indicated as sporadic ("SP").

DTC Table (P0102, P0103. P0112. P0113, P0116, P0117 & P0118). Scheme 16

1. To check MAF sensor, see «MASS AIR FLOW (MAF) SENSOR, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__mass-air-flow-maf-sensor-checking) .
2. To check IAT sensor, see «INTAKE AIR TEMPERATURE (IAT) SENSOR, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__intake-air-temperature-iat-sensor-checking) .
3. To check ECT sensor, see «ENGINE COOLANT TEMPERATURE (ECT) SENSOR, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__engine-coolant-temperature-ect-sensor-checking) .

DTC Table (P0121, P0122, P0123, P0130, P0131, P0132, P0133 & P0134). Scheme 17

1. To check TP sensor, see «THROTTLE POSITION (TP) SENSOR, CHECKING AND ADJUSTING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__throttle-position-tp-sensor-checking-and) .
2. To check HO2S G39, see «OXYGEN SENSOR (O2S) CONTROL, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__oxygen-sensor-o2s-control-checking) .

DTC Table (P0136, P0137, P0138, P0140, P0150, P0151, P0152, P0153 & P0154). Scheme 18

1. To check O2S G130 behind TWC, see «OXYGEN SENSOR (O2S) BEHIND THREE WAY CATALYTIC CONVERTER (TWC), CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
2. To check HO2S 2 G108, see «HEATED OXYGEN SENSOR (HO2S), CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .

DTC Table (P0156, P0157, P0158 & P0160). Scheme 19

1. To check O2S G131 behind TWC, see «OXYGEN SENSOR (O2S) BEHIND THREE WAY CATALYTIC CONVERTER (TWC), CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .

DTC Table (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 & P0308). Scheme 20

1. To check for cause of misfire, see «MISFIRE RECOGNITION, CHECKING»(/audi/a8/d2-1994-1999/remont/ignition-system/#ignitionglow-plug-system-37l-42l-v8-aew-abz__misfire-recognition-checking) .
2. To check fuel tank level, see «FUEL LEVEL STATUS, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__fuel-level-status-checking) .

DTC Table (P0321, P0322, P0327, P0328, P0332, P0333, P0422, P0432 & P0441). Scheme 21

1. To check Engine Speed (RPM) sensor, see «ENGINE SPEED (RPM) SIGNAL, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__engine-speed-rpm-signal-checking) .
2. To check Knock Sensor 1 G61, see «KNOCK CONTROL, CHECKING»(/audi/a8/d2-1994-1999/remont/ignition-system/#ignitionglow-plug-system-37l-42l-v8-aew-abz__knock-control-checking) .
3. To check HO2S, see «HEATED OXYGEN SENSOR (HO2S), CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
4. To check HO2S behind TWC, see «OXYGEN SENSOR (O2S) BEHIND THREE WAY CATALYTIC CONVERTER (TWC), CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
5. To check EVAP canister purge regulator valve, see «FUNCTION, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__function-checking) .

DTC Table (P0442, P0455, P0501, P0560, P0562 & P0563). Scheme 22

1. To check EVAP system, see «EVAPORATIVE EMISSIONS (EVAP) CONTROL SYSTEM, SERVICING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__evaporative-emissions-evap-control-system-servicing) .
2. To check VSS signal, see «VEHICLE SPEED SENSOR (VSS) SIGNAL, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__vehicle-speed-sensor-vss-signal-checking) .
3. To check ECM voltage supply, see «ENGINE CONTROL MODULE (ECM) POWER SUPPLY CHECKING»(/audi/a8/d2-1994-1999/remont/ignition-system/#ignitionglow-plug-system-37l-42l-v8-aew-abz) .

DTC Table (P0601, P0604, P1102, P1105, P1107 & P1110). Scheme 23

1. To replace ECM, see «MOTRONIC MULTIPORT FUEL INJECTION (MFI) SYSTEM, SERVICING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
2. To check O2S heater, see «OXYGEN SENSOR (O2S) HEATING, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__oxygen-sensor-o2s-heating-checking) .

DTC Table (P1127, P1128, P1129, P1130, P1136, P1137, P1138, P1139). Scheme 24

Note. The term "mult." = multiplicative; applies to entire engine speed (RPM) and load range.

1. To check fuel pressure and fuel pressure regulator, see «FUEL PRESSURE REGULATOR AND RESIDUAL FUEL PRESSURE, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__fuel-pressure-regulator-and-residual-fuel) .
2. To check HO2S, see «OXYGEN SENSOR (O2S) CONTROL, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__oxygen-sensor-o2s-control-checking) .
3. To check fuel injectors, see «FUEL INJECTORS, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
4. To check fuel tank level, see «FUEL LEVEL STATUS, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__fuel-level-status-checking) .
5. To check MAF sensor, see «MASS AIR FLOW (MAF) SENSOR, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__mass-air-flow-maf-sensor-checking) .
6. To check EVAP canister purge valve, see «FUNCTION, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__function-checking) .

DTC Table (P1141, P1176, P1177, P1196, P1197, P1198 & P1199). Scheme 25

1. To check MAF sensor, see «MASS AIR FLOW (MAF) SENSOR, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__mass-air-flow-maf-sensor-checking) .
2. To check TP sensor, see «THROTTLE POSITION (TP) SENSOR, CHECKING AND ADJUSTING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__throttle-position-tp-sensor-checking-and) .
3. To check HO2S, see «OXYGEN SENSOR (O2S) CONTROL, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__oxygen-sensor-o2s-control-checking) .

DTC Table (P1201, P1202, P1203, P1204, P1205, P1206, P1207 & P1208). Scheme 26

1. To check fuel injectors, see «FUEL INJECTORS, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .

DTC Table (P1213, P1214, P1215, P1216, P1217, P1218, P1219, P1220, P1250, P1280, P1283 & P1286). Scheme 27

1. To check fuel injectors, see «FUEL INJECTORS, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
2. To check fuel tank level, see «FUEL LEVEL STATUS, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__fuel-level-status-checking) .
3. To check air control valve for fuel injectors N212, see «AIR CONTROL VALVE FOR FUEL INJECTORS, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .

DTC Table (P1325, P1326, P1327, P1328, P1329, P1330, P1331, P1332 & P1386). Scheme 28

1. To check knock control, see «KNOCK CONTROL, CHECKING»(/audi/a8/d2-1994-1999/remont/ignition-system/#ignitionglow-plug-system-37l-42l-v8-aew-abz__knock-control-checking) .
2. To replace ECM, see «MOTRONIC MULTIPORT FUEL INJECTION (MFI) SYSTEM, SERVICING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .

DTC Table (P1391, P1392, P1409, P1410, P1470, P1471, P1475 & P1476). Scheme 29

1. To check CMP sensor, see «CAMSHAFT POSITION (CMP) SENSOR, CHECKING»(/audi/a8/d2-1994-1999/remont/ignition-system/#ignitionglow-plug-system-37l-42l-v8-aew-abz__camshaft-position-cmp-sensor-checking) .
2. To check EVAP canister purge valve, see «FUNCTION, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__function-checking) .
3. To check leak detection pump, see «LEAK DETECTION PUMP (LDP) -V144-, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
4. To check EVAP system, see «EVAPORATIVE EMISSIONS (EVAP) CONTROL SYSTEM, SERVICING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__evaporative-emissions-evap-control-system-servicing) .

DTC Table (P1500, P1502, P1505, P1506, P1507, P1508, P1509 & P1510). Scheme 30

1. To check fuel pump relay, see «FUEL PUMP RELAY, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__fuel-pump-relay-checking) .
2. To check CTP switch, see «CLOSED THROTTLE POSITION (CTP) SWITCH, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__closed-throttle-position-ctp-switch-checking) .
3. To check idle air control, see «IDLE AIR CONTROL (IAC), CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .

DTC Table (P1511, P1512, P1517, P1518, P1560, P1602, P1606, P1612 & P1624). Scheme 31

1. To check intake manifold tuning valve, see «INTAKE MANIFOLD TUNING (IMT) VALVE, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
2. To check ECM power supply relay, see «MOTRONIC ECM POWER SUPPLY RELAY, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__motronic-ecm-power-supply-relay-checking) .
3. To check ECM voltage supply, see «ENGINE CONTROL MODULE (ECM) POWER SUPPLY CHECKING»(/audi/a8/d2-1994-1999/remont/ignition-system/#ignitionglow-plug-system-37l-42l-v8-aew-abz) .
4. To check traction control signal, see «TRACTION CONTROL (ASR) SIGNAL, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__traction-control-asr-signal-checking) .
5. «MOTRONIC MULTIPORT FUEL INJECTION (MFI) SYSTEM, SERVICING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz)

1. To check CAN bus, see «ADDITIONAL SIGNALS, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
2. To replace ECM, see «MOTRONIC MULTIPORT FUEL INJECTION (MFI) SYSTEM, SERVICING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
3. To check MIL operation, see «MALFUNCTION INDICATOR LAMP (MIL) FUNCTION, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__malfunction-indicator-lamp-mil-function-checking) .

1. Malfunctions indicated by DTCs repaired

Note. Readiness code must be generated if DTC memory has been erased. See READINESS CODE, GENERATING .

Erasing DTC memory

1. Connect VAG1551 or VAG 1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (engine idling). See «VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .

Indicated on display

V.A.G 1551 Scan Tool Display - Erasing DTC Memory (1 Of 4). Scheme 32

1. Press buttons -0- and -2- to select "Check DTC Memory" (scan tool function 02), and press -Q- button to confirm input.
2. Indicated on display see scheme 34: V.A.G 1551 Scan Tool Display - Erasing DTC Memory (2 Of 4)
3. Press --> button until all stored DTCs have been displayed in sequence.
4. Press buttons -0- and -5- to select "Erase DTC Memory" (scan tool function 05), and press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Erasing DTC Memory (3 Of 4). Scheme 33

1. Press --> button to advance program sequence.

Indicated on display

V.A.G 1551 Scan Tool Display - Erasing DTC Memory (4 Of 4). Scheme 34

1. Press buttons -0- and -6- to select "End Output" (scan tool function 06), and press -Q- button to confirm input.
2. Road test.
3. Check DTC memory once again. Memory must be clear-no DTCs stored in memory.
4. Generate new readiness code. See «READINESS CODE, GENERATING»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .

Output Diagnostic Test Mode (DTM), (scan tool function 03)

Note. The output Diagnostic Test Mode (DTM) can only be carried out with the ignition switched on and the engine not running. The output DTM is interrupted if the engine is started or a rotary pulse is recognized. During the output DTM, the individual outputs are actuated until the scan tool program sequence is continued by pressing the --> button. Output signals are checked by listening for the sound of the component being actuated, or by feeling for mechanical evidence of actuation (clicking, vibration, etc.). Without letting the engine run briefly, switch the ignition off for approx. 20 seconds before repeating the output DTM.

Actuating sequence

1. Cyl. 1 fuel injector -N30
2. Cyl. 2 fuel injector -N31
3. Cyl. 3 fuel injector -N32
4. Cyl. 4 fuel injector -N33
5. Cyl. 5 fuel injector -N83
6. Cyl. 6 fuel injector -N84
7. Cyl. 7 fuel injector -N85
8. Cyl. 8 fuel injector -N86
9. Idle Air Control (IAC) valve -N71
10. EVAP canister purge regulator valve -N80
11. Intake manifold change-over valve -N156

Procedure

1. Connect VAG1551 or VAG1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (ignition switched on). See «VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .

Indicated on display

V.A.G 1551 Scan Tool Display - Output Diagnostic Test Mode (DTM) (1 Of 7). Scheme 35

1. Press buttons -0- and -3- to select "Output Diagnostic Test Mode" (scan tool function 03).

Indicated on display

V.A.G 1551 Scan Tool Display - Output Diagnostic Test Mode (DTM) (2 Of 7). Scheme 36

1. Press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Output Diagnostic Test Mode (DTM) (3 Of 7). Scheme 37

1. Begin test by partially opening throttle (closed throttle position switch open). Fuel injector will be heard and felt to click 5 times. see scheme 40: Identifying Partially Opening Throttle
2. All remaining fuel injectors are checked in sequence by pressing --> button on VAG1551 scan tool.

If one or more fuel injectors are not actuated

1. Check fuel injectors. See «FUEL INJECTORS, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) . When all fuel injectors have been activated by the test sequence, pressing the --> button will advance the program sequence to the next component.

Indicated on display

V.A.G 1551 Scan Tool Display - Output Diagnostic Test Mode (DTM) (4 Of 7). Scheme 38

The Idle Air Control (IAC) valve will click until the test sequence is advanced by pressing the --> button.

If not

1. Check IAC valve. See «IDLE AIR CONTROL (IAC) VALVE, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
2. Press --> button to advance program sequence.

Indicated on display

V.A.G 1551 Scan Tool Display - Output Diagnostic Test Mode (DTM) (5 Of 7). Scheme 39

The EVAP canister purge regulator valve will click until the test sequence is advanced by pressing the --> button.

If not

1. Check EVAP canister purge regulator valve. See «EVAPORATIVE EMISSIONS (EVAP) CANISTER PURGE REGULATOR VALVE, ELECTRICAL TESTING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
2. Press --> button to advance program sequence.

Indicated on display

V.A.G 1551 Scan Tool Display - Output Diagnostic Test Mode (DTM) (6 Of 7). Scheme 40

The Intake Manifold Tuning (IMT) valve will click until the test sequence is advanced by pressing the --> button.

If not

1. Check valve. See «INTAKE MANIFOLD TUNING (IMT) VALVE, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .

Indicated on display

V.A.G 1551 Scan Tool Display - Output Diagnostic Test Mode (DTM) (7 Of 7). Scheme 41

Note. To end the output Diagnostic Test Mode (DTM), press buttons -0- and -6- to select "End Output" (scan tool function 06), and press the -Q- button to confirm input.

Basic Setting, (scan tool function 04)

1. Disconnecting the battery or the Engine Control Module (ECM) harness connector will erase all learned and adapted values stored in the ECM.
2. Do not initiate basic setting when a DTC that affects oxygen sensor (O2S) operation is stored in DTC memory (does not apply to DTCs shown as "sporadic").
3. In the initial learning phase after establishing basic setting, engine idle and driveability may be affected. In this case, let the engine run at idle for a few minutes until the learning process is completed.
4. All values indicated in "Read Measuring Value Block" (scan tool function 08) remain unaffected.
5. Display group 000 shows values in decimal form. After "Basic Setting" (scan tool function 04) is entered, the ECM carries out the following operations
6. Evaporative Emissions (EVAP) canister purge regulator valve is closed.
7. Learning values for Oxygen Sensor (O2S) control are reestablished.

1. Engine temperature at least 85 ° C (185 ° F)
2. All electrical consumers switched off
3. A/C system switched off
4. Do not operate accelerator pedal
5. No malfunctions stored in DTC memory

Basic setting

1. Connect VAG1551 or VAG1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01. See «VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .
2. Check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) . There must be no malfunctions stored If necessary repair malfunction, erase DTC memory and test drive, stop engine and start again, test drive and, as a check, check DTC memory again
3. Let engine run at idle.

Indicated on display

V.A.G 1551 Scan Tool Display - Basic Setting (1 Of 4). Scheme 42

1. Press buttons -0- and -4- to select "Basic Setting" (scan tool function 04).

Indicated on display

V.A.G 1551 Scan Tool Display - Basic Setting (2 Of 4). Scheme 43

1. Press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Basic Setting (3 Of 4). Scheme 44

1. Input display group number 000. (Scheme 46) NOTE: Display group number 000 is an example used here to illustrate the sequence of operations for selecting a display group.
2. Press -0- button three times (doing so enters display group number 000).
3. Press -Q- button to confirm input.

Indicated on display (1-10 = display fields. (Scheme 46)

V.A.G 1551 Scan Tool Display - Basic Setting (4 Of 4). Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

1. Allow engine to run until reaching normal operating temperature, approx. 85° C (185°F). Value in display field 1 must be a minimum of 170 NOTE: A copy of the display is available by pressing the PRINT button on the VAG1551 scan tool (Scheme 46): Basic Setting: Function 04, Display Group 000
2. If displayed values are outside the specified range. (Scheme 47)
3. Proceed as follows: NOTE: To exit "Basic Setting" (scan tool function 04)
4. Press --> button.
5. Press buttons -0- and -6- to select "End Output" (scan tool function 06).
6. Press -Q- button to confirm input. (Scheme 47): Basic Setting: Display Group 000, Display Fields 1, 2 & 3 To check ECT sensor, see «ENGINE COOLANT TEMPERATURE (ECT) SENSOR, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__engine-coolant-temperature-ect-sensor-checking). To check IAC valve N71, see «IDLE AIR CONTROL (IAC) VALVE, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz). (Scheme 48): Basic Setting: Display Group 000, Display Fields 4, 5 & 6 To check IAC valve N71, see «IDLE AIR CONTROL (IAC) VALVE, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz). To check MAF sensor, see «MASS AIR FLOW (MAF) SENSOR, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__mass-air-flow-maf-sensor-checking). (Scheme 49): Basic Setting: Display Group 000, Display Fields 7, 8, 9 & 10 To check HO2S, see «HEATED OXYGEN SENSOR (HO2S), CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz). To check fuel pressure regulator and residual pressure, see «FUEL PRESSURE REGULATOR AND RESIDUAL FUEL PRESSURE, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__fuel-pressure-regulator-and-residual-fuel).
7. If all display fields display values as specified, Press --> button to advance program sequence. Indicated on display see scheme 53: V.A.G 1551 Scan Tool Display - Select Function XX
8. Press buttons -0- and -6- to select "End Output" (scan tool function 06).

Indicated on display

V.A.G 1551 Scan Tool Display - 06 End Output. Scheme 50

1. Press -Q- button to confirm input.

Engine Control Module (ECM) coding, checking

If vehicle coding information is not as specified

1. Replace ECM. NOTE: Vehicle information is "hard coded" into the ECM. Service coding of the ECM is not possible. Coding versions may be checked (only) using the VAG1551 or VAG1552 Scan Tool (ST). While checking coding versions, the 5-digit ECM code must always be displayed.
2. Connect VAG1551 or VAG1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (ignition switched on). See «VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Engine Control Module (ECM) Coding (1 Of 3). Scheme 51

1. Press -Q- button to confirm input. Indicated on display (ECM identification and coding) see scheme 56: V.A.G 1551 Scan Tool Display - Checking Engine Control Module (ECM) Coding (2 Of 3) ECM CODING AND MODEL Coding Model 01273 A8 4.2 liter, engine code ABZ 01153 A8 3.7 liter, engine code AEW
2. Advance program sequence by pressing button.

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Engine Control Module (ECM) Coding (3 Of 3). Scheme 52

1. Press buttons -0- and -6- to select "End Output" (scan tool function 06), and press -Q- button to confirm input.

Readiness code, checking (m.y. 1997)

Note. To check the readiness code for m.y. 1998, see READINESS CODE, CHECKING (M.Y. 1998) .

1. Connect VAG1551 or VAG1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (ignition switched on). See «VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Readiness Code (M.Y. 1997) (1 Of 4). Scheme 53

1. Press buttons -0- and -8- to select "Read Measuring Value Block" function 08.

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Readiness Code (M.Y. 1997) (2 Of 4). Scheme 54

1. Press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Readiness Code (M.Y. 1997) (3 Of 4). Scheme 55

1. Press buttons -0-, -3- and -6- to input display group number 36 (036).

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Readiness Code (M.Y. 1997) (4 Of 4). Scheme 56

1. Press -Q- button to confirm input.

Specified value in display field 1: all values should be "0.", (if readiness code is set).

If the readiness code is not set

1. Generate readiness code. See «READINESS CODE, GENERATING»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz). see scheme 62: Read Measuring Value Block: Identifying Display Group 36 (M.Y. 1997)

Note for display field 1

This display field indicates the diagnostic status present in memory. Whenever DTC memory is erased, the ECM harness connector is disconnected from the ECM, or the battery is disconnected, all values will automatically be set to 1 (not ready). After successful diagnosis (re-generation of readiness code) all values will be set to 0.

Note for display fields 2, 3 and 4

These display fields indicate the diagnostic status present in memory since last starting the engine. Stopping the engine automatically sets diagnostic status to 1. After successful diagnosis, these values will be set to 0.

Read Measuring Value Block: Display Group 36, Display Field 1 (M.Y. 1997). Scheme 57

1. To generate readiness code, see «READINESS CODE, GENERATING (M.Y. 1997)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__readiness-code-generating-my-1997) .

Read Measuring Value Block: Display Group 36, Display Field 2 (M.Y. 1997). Scheme 58

Read Measuring Value Block: Display Group 36, Display Field 3 (M.Y. 1997). Scheme 59

Read Measuring Value Block: Display Group 36, Display Field 4 (M.Y. 1997). Scheme 60

Readiness code, checking (m.y. 1998)

Note. To check the readiness code for m.y. 1997, see READINESS CODE, CHECKING .

1. Connect VAG1551 or VAG1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (with ignition switched on). See «VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) .

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Readiness Code (M.Y. 1998) (1 Of 4). Scheme 61

1. Press buttons -0- and -8- to select "Read Measuring Value Block" function 08.

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Readiness Code (M.Y. 1998) (2 Of 4). Scheme 62

1. Press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Readiness Code (M.Y. 1998) (3 Of 4). Scheme 63

1. Press buttons -0-, -3- and -6- to input display group number 36 (036).

Indicated on display

V.A.G 1551 Scan Tool Display - Checking Readiness Code (M.Y. 1998) (4 Of 4). Scheme 64

1. Press -Q- button to confirm input. Specified value in display field 1: all digits should be "0", (if readiness code is set).

If the readiness code is not set

1. Generate readiness code. See «READINESS CODE, GENERATING (M.Y. 1998)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__readiness-code-generating-my-1998). see scheme 71: Read Measuring Value Block: Identifying Display Group 36 (M.Y. 1998)

Note for display field 1

This display field indicates the diagnostic status present in memory. Whenever DTC memory is erased, the ECM harness connector is disconnected from the ECM or the battery is disconnected, all values will automatically be set to 1 (not ready). After successful diagnosis (re-generation of readiness code) all values will be set to 0.

Note for display fields 2, 3 and 4

These display fields indicate the diagnostic status present in memory since last starting the engine. Stopping the engine automatically sets diagnostic status to 1. After successful diagnosis, these values will be set to 0.

Read Measuring Value Block: Display Group 36, Display Field 1 (M.Y. 1998). Scheme 65

1. To generate readiness code, see «READINESS CODE, GENERATING (M.Y. 1998)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__readiness-code-generating-my-1998) .

Read Measuring Value Block: Display Group 36, Display Field 2 (M.Y. 1998). Scheme 66

Read Measuring Value Block: Display Group 36, Display Field 3 (M.Y. 1998). Scheme 67

Read Measuring Value Block: Display Group 36, Display Field 4 (M.Y. 1998). Scheme 68

Readiness code, generating (m.y. 1997)

Note. To generate the readiness code for m.y. 1998, see READINESS CODE, GENERATING (M.Y. 1998) . There must be no malfunctions stored in DTC memory. During the procedure, the engine must not be stopped. If specified values are attained before the minimum time allowed, the test sequence may be advanced.

1. Engine temperature at least 85° C (185° F).

1. Connect VAG1551 or VAG1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (engine idling). See «VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) . NOTE: To change to a different display group, proceed as follows: CHANGE TO A DIFFERENT DISPLAY GROUP Function VAG1551 VAG1552 04 - Basic Setting Press button -4- Press button -4- 08 - Read Measuring Value Block Press button -8- Press button -8- Display group VAG1551 VAG1552 Next higher number Press button -3- Press up arrow button Next lower number Press button -1- Press down arrow button Skip Press -C-button Press -C-button

Step 1: Check DTC memory

Indicated on display

V.A.G 1551 Scan Tool Display - Checking DTC Memory (1 Of 2). Scheme 69

1. Press buttons -0- and -2- to select "Check DTC Memory" function 02, and press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Checking DTC Memory (2 Of 2). Scheme 70

1. Press --> button to advance program sequence.

Step 2: Erase DTC Memory

Indicated on display

V.A.G 1551 Scan Tool Display - Erasing DTC Memory (1 Of 2). Scheme 71

1. Press buttons -0- and -5- to select "Erase DTC Memory" function 05, and press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Erasing DTC Memory (2 Of 2). Scheme 72

1. Press --> button to advance program sequence.

Step 3: Heated Oxygen Sensor (HO2S) and Heated Oxygen Sensor (HO2S) 2 (bank 1 and bank 2), readiness

Indicated on display

V.A.G 1551 Scan Tool Display - Heated Oxygen Sensor And Heated Oxygen Sensor Readiness, 1997 (1 Of 4). Scheme 73

1. Press buttons -0- and -8- to select "Read Measuring Value Block" function 08, and press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Heated Oxygen Sensor And Heated Oxygen Sensor Readiness, 1997 (2 Of 4). Scheme 74

1. Press buttons -0-, -2- and -6- to input display group number 26 (026), and press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Heated Oxygen Sensor And Heated Oxygen Sensor Readiness, 1997 (3 Of 4). Scheme 75

Display Group 26: HO2S And HO2S2, Readiness, 1997 (Idle). Scheme 76

1. Specified value in display field 3: "B1-S1 ON" (after 5 min.)
2. Specified value in display field 4: "B2-S1 ON" (after 5 min.)

If "OFF" appears in display field 3 or 4

1. Check heated oxygen sensor ( «HEATED OXYGEN SENSOR (HO2S), CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) ) and oxygen sensor heater ( «OXYGEN SENSOR (O2S) HEATING, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__oxygen-sensor-o2s-heating-checking) ).
2. Press buttons -0- and -4- to select "Basic Setting" function 04.
3. Press -3- button three times (VAG1551) to advance to display group 29.

Indicated on display

V.A.G 1551 Scan Tool Display - Heated Oxygen Sensor And Heated Oxygen Sensor Readiness, 1997 (4 Of 4). Scheme 77

Display Group 29: Oxygen Sensor Aging (Bank1), 1997. Scheme 78

1. Three way catalytic converter temperature greater than 300° C (display field 2)

1. Raise engine speed (display field 1) to between 1800 and 2200 RPM, and hold until display field 4 changes from "Test OFF" to "Test ON."
2. Maintain RPM until display field 4 indicates "B1-S1 OK." If display field 4 changes to "B1-S1 n.OK" check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
3. Press -3- button once to advance to display group 30.

Indicated on display

V.A.G 1551 Scan Tool Display - Oxygen Sensor Aging Diagnosis, Bank 1, 1997. Scheme 79

Display Group 30: Oxygen Sensor Aging (Bank2), 1997. Scheme 80

1. Three way catalytic converter temperature greater than 300° C (display field 2)

1. Raise engine speed to between 1800 and 2200 RPM, and hold until display field 4 changes from "Test OFF" to "Test ON."
2. Maintain RPM until display field 4 indicates "B2-S1 OK." If display field 4 changes to "B2-S1 n.OK" check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
3. Press -3- button once to advance to display group 31.

Indicated on display

V.A.G 1551 Scan Tool Display - Oxygen Sensor Aging Diagnosis, Bank 2 - 1997. Scheme 81

Display Group 31: Three Way Catalytic Converter (TWC) Diagnosis, Bank 1 - 1997. Scheme 82

1. TWC temperature greater than 300° C (display field 2)

1. Raise engine speed to between 1800 and 2200 RPM, and hold until display field 4 changes from "Test OFF" to "Test ON." Test duration approx. 60 seconds.
2. Maintain RPM until display field 4 indicates "Cat B1 OK."
3. If display field 4 changes to "Cat B1 n.OK" check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
4. Press -3- button once to advance to display group 32.

Indicated on display

V.A.G 1551 Scan Tool Display - Three Way Catalytic Converter (TWC) Diagnosis, Bank 1 - 1997. Scheme 83

Display Group 32: Three Way Catalytic Converter (TWC) Diagnosis, Bank 2 - 1997. Scheme 84

1. TWC temperature greater than 300 ° C (display field 2)

1. Raise engine speed to between 1800 and 2200 RPM and hold until display field 4 changes from "Test OFF" to "Test ON."
2. Test duration approx. 60 seconds.
3. Maintain RPM until display field 4 indicates "Cat B2 OK.'
4. If display field 4 changes to "Cat B2 n.OK" check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
5. Press -3- button once to advance to display group 33.

Indicated on display

V.A.G 1551 Scan Tool Display - Three Way Catalytic Converter (TWC) Diagnosis, Bank 2. Scheme 85

Display Group 33: EVAP Canister Purge Regulator Valve Diagnosis, 1997. Scheme 86

1. After diagnosis is selected, display field 4 must change from "Test OFF" to "Test ON."
2. After diagnosis, value in display field 4 must be "EVAP OK."

Note. If during diagnosis the display changes from "Test ON" to "Test OFF" apply the throttle briefly to start the test again.

1. If display field 4 changes to "EVAP n.OK" check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
2. Press --> button to advance program sequence.

Indicated on display

V.A.G 1551 Scan Tool Display - EVAP Canister Purge Regulator Valve Diagnosis, 1997 (1 Of 3). Scheme 87

When all display fields indicate "0" and no malfunctions are stored in DTC memory, the OBD II function check is successful.

1. Press buttons -0- and -8- to select function "Read Measuring Value Block" function 08, and press -Q- button to confirm input. (Scheme 88): V.A.G 1551 Scan Tool Display - EVAP Canister Purge Regulator Valve Diagnosis, 1997 (2 Of 3)

Indicated on display

Scheme 88

1. Press buttons -0-, -3- and -6- to input display group number 36 (036), and press -Q- button to confirm input. see scheme 96: V.A.G 1551 Scan Tool Display - EVAP Canister Purge Regulator Valve Diagnosis, 1997 (3 Of 3)

Indicated on display

Reading Measuring Value Block 36, 1997. Scheme 89

1. Press --> button to advance program sequence.
2. Press buttons -0- and -6- to select "End Output" function 06, and press -Q- button to confirm input.

Readiness code, generating (m.y. 1998)

Note. To generate the readiness code for m.y. 1997, see READINESS CODE, GENERATING . There must be no malfunctions stored in DTC memory. During the procedure, the engine must not be stopped. If specified values are attained before the minimum time allowed, the test sequence may be advanced.

1. Engine temperature at least 85° C (185° F)

1. Connect VAG1551 or VAG1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (with engine idling). See «VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz) . NOTE: To change to a different display group, proceed as follows: CHANGING TO A DIFFERENT DISPLAY GROUP Function VAG1551 VAG1552 04 - Basic Setting Press button -4- Press button -4- 08 - Read Measuring Value Block Press button -8- Press button -8- Display group VAG1551 VAG1552 Next higher number Press button -3- Press up arrow button Next lower number Press button -1- Press down arrow button Skip Press -C-button Press -C-button

Scheme 90

1. Indicated on display (Scheme 90): V.A.G 1551 Scan Tool Display - Checking DTC Memory (1 Of 2) Press buttons -0- and -2- to select "Check DTC Memory" function 02, and press -Q- button to confirm input Indicated on display see scheme 99: V.A.G 1551 Scan Tool Display - Checking DTC Memory (2 Of 2) Press --> button to advance program sequence.

Indicated on display

V.A.G 1551 Scan Tool Display - Erasing DTC Memory (1 Of 2). Scheme 91

1. Press buttons -0- and -5- to select "Erase DTC Memory" function 05, and press -Q-button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Erasing DTC Memory (2 Of 2). Scheme 92

1. Press --> button to advance program sequence.

Indicated on display

V.A.G 1551 Scan Tool Display - Heated Oxygen Sensor and Heated Oxygen Sensor Readiness, 1998 (1 Of 4). Scheme 93

1. Press buttons -0- and -8- to select "Read Measuring Value Block" function 08, and press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Heated Oxygen Sensor and Heated Oxygen Sensor Readiness, 1998 (2 Of 4). Scheme 94

1. Press buttons -0-, -2- and -6- to input display group number 26 (026), and press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Heated Oxygen Sensor and Heated Oxygen Sensor Readiness, 1998 (3 Of 4). Scheme 95

Display Group 26: HO2S And HO2S2, Readiness (Idle), 1998. Scheme 96

1. Specified value in display field 3: "B1-S1 ON" (after 5 min.)
2. Specified value in display field 4: "B2-S1 ON" (after 5 min.)

If "OFF" appears in display field 3 or 4

1. Check heated oxygen sensor ( «HEATED OXYGEN SENSOR (HO2S), CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) ) and oxygen sensor heater ( «OXYGEN SENSOR (O2S) HEATING, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__oxygen-sensor-o2s-heating-checking) ).
2. Press button -4- to select "Basic Setting" function 04.
3. Press -3- button three times to advance to display group 29.

Indicated on display

V.A.G 1551 Scan Tool Display - Heated Oxygen Sensor and Heated Oxygen Sensor Readiness, 1998 (4 Of 4). Scheme 97

Display Group 29: Oxygen Sensor Aging (Bank 1), 1998. Scheme 98

1. TWC temperature greater than 300°C (display field 2)

1. Raise engine speed (display field 1) to 1800-2200 RPM, and hold until display field 4 changes from "Test OFF" to "Test ON."
2. Maintain RPM until display field 4 indicates "B1-S1 OK."
3. If display field 4 changes to "B1-S1 n.OK" check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
4. Press button -3- once to advance to display group 30.

Indicated on display

V.A.G 1551 Scan Tool Display - Oxygen Sensor Aging Diagnosis, Bank 1. Scheme 99

Display Group 30: Oxygen Sensor Aging (Bank 2), 1998. Scheme 100

1. TWC temperature greater than 300° C (display field 2)

1. Raise engine speed to 1800-2200 RPM, and hold until display field 4 changes from "Test OFF" to "Test ON."
2. Maintain RPM until display field 4 indicates "B2-S1 OK."
3. If display field 4 changes to "B2-S1 n.OK" check DTC memory. See «Check Diagnostic Trouble Code (DTC) Memory, (scan tool function 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
4. Press button -3- once to advance to display group 31.

Indicated on display

V.A.G 1551 Scan Tool Display - Oxygen Sensor Aging Diagnosis, Bank 2 - 1998. Scheme 101

Display Group 31: Three Way Catalytic Converter (TWC) Diagnosis Bank 1, 1998. Scheme 102

1. TWC temperature greater than 300° C (display field 2)

1. Raise engine speed to 1800-2200 RPM, and hold until display field 4 changes from "Test OFF" to "Test ON." Test duration approx. 60 seconds.
2. Maintain RPM until display field 4 indicates "Cat B1 OK."
3. If display field 4 changes to "Cat B1 n.OK" check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
4. Press button -3- once to advance to display group 32.

Indicated on display

V.A.G 1551 Scan Tool Display - Three Way Catalytic Converter (TWC) Diagnosis Bank 1, 1998. Scheme 103

Display Group 32: Three Way Catalytic Converter (TWC) Diagnosis Bank 2, 1998. Scheme 104

1. TWC temperature greater than 300° C (display field 2)

1. Raise engine speed to 1800-2200 RPM and hold until display field 4 changes from "Test OFF" to "Test ON." Test duration: approx. 60 seconds.
2. Maintain RPM until display field 4 indicates "Cat B2 OK."
3. If display field 4 changes to "Cat B2 n.OK" check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
4. Press button -3- once to advance to display group 33.

Indicated on display

V.A.G 1551 Scan Tool Display - Three Way Catalytic Converter (TWC) Diagnosis Bank 2 - 1998. Scheme 105

Display Group 33: EVAP Canister Purge Regulator Valve Diagnosis, 1998. Scheme 106

1. After diagnosis is selected, display field 4 must change from "Test OFF" to "Test ON."
2. After diagnosis, value in display field 4 must be "EVAP OK."

Note. If during diagnosis the display changes from "Test ON" to "Test OFF" apply the throttle briefly to start the test again.

1. If display field 4 changes to "EVAP n.OK" check DTC memory. See «CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
2. Press button -3- once to advance to display group 34.

Indicated on display

V.A.G 1551 Scan Tool Display - EVAP Canister Purge Regulator Valve Diagnosis, 1998. Scheme 107

Display Group 34: Fuel Tank Leak Detection, 1998. Scheme 108

1. After diagnosis is selected, display field 4 must change from "Test OFF" to "Test ON." NOTE: If display field 4 changes from "Test ON" to "Test OFF" and "Abort" appears in display field 2, shut the engine off, start the engine again and repeat the diagnosis of fuel tank leak detection.
2. After diagnosis, value in display field 4 must be "Syst. OK."

1. If display field 4 changes to "Syst. n.OK" check DTC memory. See «Check Diagnostic Trouble Code (DTC) Memory, (scan tool function 02)»(/audi/a8/d2-1994-1999/remont/ignition-system/#on-board-diagnostic-obd-37l-42l-v8-aew-abz__check-diagnostic-trouble-code-dtc-memory) .
2. Press --> button to advance program sequence.

Indicated on display

V.A.G 1551 Scan Tool Display - Detecting Fuel Tank Leak, 1998 (1 Of 3). Scheme 109

1. Press buttons -0- and -8- to select "Read Measuring Value Block" function 08, and press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Detecting Fuel Tank Leak, 1998 (2 Of 3). Scheme 110

1. Press buttons -0-, -3- and -6- to input display group number 36 (036), and press -Q- button to confirm input.

Indicated on display

V.A.G 1551 Scan Tool Display - Detecting Fuel Tank Leak, 1998 (3 Of 3). Scheme 111

Reading Measuring Block 36, 1998. Scheme 112

When all display fields indicate "0" and no malfunctions are stored in DTC memory, the OBD function check is successful.

1. Press --> button to advance program sequence.
2. Press buttons -0- and -6- to select "End Output" function 06, and press -Q- button to confirm input.

See also:
• MASS AIR FLOW (MAF) SENSOR, CHECKING
• INTAKE AIR TEMPERATURE (IAT) SENSOR, CHECKING
• ENGINE COOLANT TEMPERATURE (ECT) SENSOR, CHECKING
• THROTTLE POSITION (TP) SENSOR, CHECKING AND ADJUSTING
• OXYGEN SENSOR (O2S) CONTROL, CHECKING
• OXYGEN SENSOR (O2S) BEHIND THREE WAY CATALYTIC CONVERTER (TWC), CHECKING
• MISFIRE RECOGNITION, CHECKING
• FUEL LEVEL STATUS, CHECKING
• ENGINE SPEED (RPM) SIGNAL, CHECKING
• KNOCK CONTROL, CHECKING
• FUNCTION, CHECKING
• EVAPORATIVE EMISSIONS (EVAP) CONTROL SYSTEM, SERVICING
• VEHICLE SPEED SENSOR (VSS) SIGNAL, CHECKING
• ENGINE CONTROL MODULE (ECM) POWER SUPPLY CHECKING
• OXYGEN SENSOR (O2S) HEATING, CHECKING
• FUEL PRESSURE REGULATOR AND RESIDUAL FUEL PRESSURE, CHECKING
• CAMSHAFT POSITION (CMP) SENSOR, CHECKING
• FUEL PUMP RELAY, CHECKING
• CLOSED THROTTLE POSITION (CTP) SWITCH, CHECKING
• MOTRONIC ECM POWER SUPPLY RELAY, CHECKING
• TRACTION CONTROL (ASR) SIGNAL, CHECKING
• MALFUNCTION INDICATOR LAMP (MIL) FUNCTION, CHECKING
• CHECK DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, (SCAN TOOL FUNCTION 02)
• ERASE DTC MEMORY, (SCAN TOOL FUNCTION 05)
• DIAGNOSTIC TROUBLE CODE (DTC) TABLE
• READINESS CODE, CHECKING (M.Y. 1998)
• READINESS CODE, GENERATING (M.Y. 1997)
• READINESS CODE, GENERATING (M.Y. 1998)