1.8l 4-cyl 5v Turbo Fuel Injection & Ignition, Engine Code(s): Atc Audi TT 8N

Technical data

Equipment

1. Data transfer between the control module and the VAS5051 vehicle diagnostic, testing and informations system or VAG1551 scan tool occurs in "Rapid data transfer" mode.
2. DTC memory is designed for permanent memory and is therefore not dependent on voltage supply.
3. Stored DTCs can be printed out by checking DTC memory. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
4. DTC memory must be erased after malfunction is repaired. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

Important

1. Readiness code must be re-generated after erasing DTC memory and when voltage supply to the Motronic ECM -J220- is interrupted. Refer to «Readiness code, generating»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__readiness-code-generating) .
2. If the ECM recognizes malfunctions that lead to a worsening of emissions values, it indicates them by lighting the Malfunction Indicator Lamp (Malfunction Indicator Lamp (MIL) -K83-). Significance of this lamp. Refer to «Malfunction Indicator Lamp (MIL), significance»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__malfunction-indicator-lamp-mil-significance) .
3. "E-Gas" relevant malfunctions are also indicated by lighting the MIL for electric accelerator mechanism ("EPC warning lamp").

Malfunction Indicator Lamp (MIL), significance

If the ECM recognizes malfunctions that lead to a worsening of emissions values, it indicates them by lighting the Malfunction Indicator Lamp for exhaust.

Scheme 178

Malfunction Indicator Lamp (MIL) for exhaust

Note. Exhaust MIL can be switched on with a blinking or steady light. DTC memory must be checked in either case. Refer to Diagnostic Trouble Code (DTC) memory, checking and erasing .

1. Blinking: There is a malfunction that damages the catalytic converter at this driving condition (e.g. combustion misfire). In this case, vehicle must only be driven at reduced power!
2. Steady light: There is a malfunction that worsens the exhaust. Check DTC memory for motronic ECM and Transmission Control Module (if installed).
3. If there are driveability problems or if there is a customer complaint and the exhaust MIL is not lit, DTC memory must be checked. There may be DTCs stored that do not cause the exhaust MIL to light immediately, but only if malfunction is recognized again after repeated engine starts.

Function test

1. Switch ignition on

Exhaust MIL must light.

If exhaust MIL does not light when ignition is switched on

1. Check wire from ECM to exhaust MIL as follows

If exhaust MIL does not light when ignition is switched on, continue test as follows

1. Start engine and run at idle

Exhaust MIL must go out after a few seconds.

If exhaust MIL does not go out

1. Check DTC Memory. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

If there are no DTCs are stored

Scan Tool (ST) and test equipment safety precautions

Model specific WARNINGS continued. Refer to Scan Tool (ST) and test equipment safety precautions, continued .

Scan Tool (ST) and test equipment safety precautions, continued

VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions

Test conditions

1. Battery voltage at least 11 V
2. Ground (GND) connections at engine and transmission OK

Procedure

Scheme 179

1. Connect VAS5051 tester to vehicle with VAS5051/1 diagnostic wire. Alternately, VAG1551 Scan Tool can also be attached using VAG1551/3B adapter.

Model specific WARNINGS continued. Refer to Scan Tool (ST) and test equipment safety precautions .

Note. The following description only explains implementation of On Board Diagnostic using VAG1551 Scan tool. When using the VAS5051 tester, observe the tester's instructions for use

Indicated on display

1) Operating modes 1 and 2 are displayed alternately

Note. If nothing appears in display Refer to Scan Tool operating instructions

Depending on desired function. Refer to Selectable functions (1 of 2)

1. Turn ignition on.

or

1. Start engine.
2. Turn printer of scan tool on using PRINT button. The lamp in the button must light up.
3. Press button 1 to select "Rapid data transfer" operating mode 1.

When indicated on display

Note. The address word 00 initiates the automatic test sequence, i.e. it results in a DTC check on all OBD capable systems in the vehicle via rapid data transfer.

1. Press buttons -0- and -1- to select address word "engine electronics" and press -Q- button to confirm input.

VAG1551 Scan Tool display indicates control module identification, e.g.

Note. Control module identification can be printed by pressing the PRINT button of the VAG1551 scan tool.

Control module identification (example)

1. Press --> button.

Indicated on display (function selection)

Note. After pressing buttons -0- and -1- to select "Check Control Module Versions" and pressing -Q- button to confirm input, you may also have control module identification displayed again. When indicated on display: Perform troubleshooting procedure

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

Selectable functions (1 of 2)

Selectable functions (2 of 2)

1. Modes 1 to 7 can be selected under address word 33.
2. Individual measured values can be read out under mode 1. Mode 1 is not recommended for authorize Audi service stations, since this data can be obtained much more accurately under address word 01/function 04 or function 08.
3. Mode 2 displays operating conditions, for which a malfunction was recognized.
4. With mode 3, DTC memory is checked and with mode 4, DTC memory is erased.

1. Mode 5 displays the static dimensions of the oxygen sensors, which are legally required. Since these dimensions are not directly relevant to oxygen sensor diagnostics, mode 5 is also insignificant for the authorized Audi service station.
2. Under mode 6, all measured values can be checked from components and systems that are not constantly monitored.
3. Using mode 7, DTCs can be checked for which the Malfunction Indicator Light (MIL) is not yet lit (MIL is not on, no DTCs under mode 3)

Diagnostic Trouble Code (DTC) memory, checking and erasing

1. Connect VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Engine should run at idle for this.

Note. If engine doesn't start, crank engine using starter for at least 5 seconds. Do not switch ignition off until after testing.

When indicated on display

1. Press buttons "02" for the function "Check DTC Memory" and press Q button to confirm input.

When indicated on display

1. Press --> button.

or

When indicated on display

When printer is switched on, stored DTCs are shown in sequence and printed.

1. Find printed DTCs in DTC table and carry out repairs as necessary. Refer to «Diagnostic Trouble Code (DTC) table»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__diagnostic-trouble-code-dtc-table) .

1. Press --> button.

When indicated on display

1. Press buttons "05" for the function "Erase DTC Memory" and press Q button to confirm input.

Note. Attention! DTC memory is not interrogated When indicated on display, the procedure was not followed exactly.

1. Check DTC memory

DTC memory will not be erased under the following conditions

1. Ignition switched off after DTC memory is checked.
2. A static malfunction was not repaired.

When indicated on display

1. Press --> button.
2. Check DTC memory again after repair work

Note. This erases DTCs that were stored during repair of malfunction, e.g. because harness connectors were disconnected.

End Output

When indicated on display

1. Press buttons -0- and -6- to select "End output" and press -Q- button to confirm input.

When indicated on display

1. Switch ignition off and disconnect Data Link Connector (DLC).

Diagnostic Trouble Code (DTC) table

Note. If malfunctions occur in monitored sensors or components, these will be stored as DTCs in the DTC memory with a description of malfunction type. "E-Gas"-relevant malfunctions are also indicated by the MIL for electric accelerator mechanism ("EPC warning lamp"). Malfunctions that worsen emissions are also indicated by an Malfunction Indicator Lamp (MIL) (MIL for output DTM) that is also located in the instrument cluster. There are malfunctions that cause the Malfunction Indicator Lamp (MIL) to light up immediately after recognition. There are also malfunctions for which the Malfunction Indicator Lamp (MIL) does not light up until repeated recognition at engine start. Malfunctions that occur only sporadically (temporary malfunctions) are identified by the letters "SP" (sporadic malfunction) on the VAG1551 scan tool display. The word sporadic means "appearing or occurring at irregular intervals, occasional." The DTC table is organized by the 5 digit code at left. If a stored DTC does not reoccur within the next 40 warm-up cycles, the DTC will be erased automatically. Do not immediately replace components that the VAG1551 suggests are malfunctioning, instead: check wire connections and harness connectors to these components according to wiring diagram. Also check Ground (GND) connections according to wiring diagram. This is particularly valid when malfunctions are displayed as "sporadically occurring" (SP). If the connector from the ECM is disconnected or the battery is disconnected, all adaptation values in the control module are erased. DTC memory content will remain intact however. If the engine is started after this, a rough, uneven idle can result. In this case, engine must be allowed to run at idle for a few minutes until adaptation procedure has been completed. After DTC memory is erased (Refer to Diagnostic Trouble Code (DTC) memory, checking and erasing ) readiness code must be re-generated. Refer to Readiness code, generating .

1) Intake manifold pressure is determined by the charge air pressure sensor -G31- (instead of -G71- as indicated), air pressure is determined by the Barometric Pressure (BARO) sensor -F96- (in ECM).

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

Note on combustion misfires

For malfunctions potentially caused by fuel shortage (e.g. combustion misfires) the DTC "P1250, Fuel Level Too Low" is also indicated. This means that combustion misfires could not be recognized on account of a technical malfunction, but rather because there is/was too little fuel in fuel tank.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

1) Brake pedal switch -F47- is monitored in addition to brake light switch -F-.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

Note. mult. = multiple, means that malfunction is valid across entire range of engine speed and engine load.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

Note. add. = additive, means that malfunction is only valid at closed throttle (idle).

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

1) For these malfunctions, ECM switches on the EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

3) For these malfunctions, ECM switches on the Malfunction Indicator Lamp (MIL) in instrument cluster immediately after recognizing the malfunction.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

1) The DTC "Fuel Level Too Low" is stored when there is/was too little fuel in fuel tank. The DTC is stored as a static malfunction and is not switched to sporadic even if fuel tank has been filled with fuel (e.g. by the customer) in the meantime. In this way, it can be determined that subsequent malfunctions were caused by lack of fuel, e.g. combustion misfires or oxygen control related malfunctions.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

1) For these malfunctions, ECM switches on the EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

3) For these malfunctions, ECM switches on the Malfunction Indicator Lamp (MIL) in instrument cluster immediately after recognizing the malfunction.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

1) ECM switches on the EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

3) ECM switches on the MIL in instrument cluster immediately after recognizing the malfunction.

4) ECM does not switch MIL on unless malfunction is recognized again after another engine start.

1) For these malfunctions, ECM switches on the EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

2) DTC is stored upon appropriate signal from airbag control module.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

1) For these malfunctions, ECM switches on the EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

3) For these malfunctions, ECM switches on the Malfunction Indicator Lamp (MIL) in instrument cluster immediately after recognizing the malfunction.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

1) ECM switches on EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

3) ECM switches on the MIL in instrument cluster immediately after recognizing the malfunction.

4) ECM does not switch on the MIL unless malfunction is recognized again after another engine start.

1) For these malfunctions, ECM switches on the EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

3) For these malfunctions, ECM switches on the Malfunction Indicator Lamp (MIL) in instrument cluster immediately after recognizing the malfunction.

1) For these malfunctions, ECM switches on the EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

3) For these malfunctions, ECM switches on the Malfunction Indicator Lamp (MIL) in instrument cluster immediately after recognizing the malfunction.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

1) For these malfunctions, ECM switches on the EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

3) For these malfunctions, ECM switches on the Malfunction Indicator Lamp (MIL) in instrument cluster immediately after recognizing the malfunction.

4) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized again after another engine start.

1) For these malfunctions, ECM switches on the EPC warning lamp in instrument cluster. Significance of EPC warning lamp. Refer to Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance .

Note. The malfunction light for power acceleration -K132- (in wiring diagram: malfunction light for power accelerator activation -K132) is also called the EPC warning lamp.

Output Diagnostic Test Mode (DTM)

Note. Output Diagnostic Test Mode is only possible with ignition switched on and engine off. Electric Fuel Pump (FP) runs during all of output Diagnostic Test Mode (DTM). During output Diagnostic Test Mode, individual actuators are activated for approximately 1 minute unless --> button is pressed first to switch to next actuator. Actuators are checked either acoustically or by touch. Output Diagnostic Test Mode is aborted if engine is started or an RPM signal is recognized. Before repeating output DTM, engine must be started. (ECM must recognize an engine speed of above 300 RPM).

The following components will be activated in the sequence listed using output Diagnostic Test Mode (DTM)

Test conditions

1. Fuse for Engine Control Module (ECM) OK
2. Fuel Pump (FP) relay OK

Test sequence

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Ignition must remain switched on for this.

When indicated on display

1. Press buttons -0- and -3- to select "output Diagnostic Test Mode" and press -Q- button to confirm input.

Indicated on display

EVAP canister purge regulator valve

1. Confirm input using the Q-button.

Indicated on display

(Indicated on VAG1551: EVAP valve -N80-)

This solenoid valve is activated for approximately 1 minute (clicks), unless --> button is pressed first to switch to the next actuator.

If valve is not activated (does not click)

1. Check Evaporative Emission (EVAP) canister purge regulator valve. Refer to «Evaporative Emission (EVAP) canister purge regulator valve -N80-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__evaporative-emission-evap-canister-purge-regulator) .

Activating secondary air inlet valve

1. Press --> button.

Indicated on display

This solenoid valve is activated for approximately 1 minute (clicks), unless --> button is pressed first to switch to the next actuator.

If valve is not activated (does not click)

1. Check secondary air inlet valve -N112-. Refer to «Secondary Air Injection (AIR) solenoid valve -N112-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

Activating secondary air pump relay

1. Press --> button.

Indicated on display

Secondary air pump relay -J299- activates the Secondary Air Injection (AIR) pump motor -V101-. This runs for about a minute in intervals, unless --> button is pressed first to switch to the next actuator.

If Secondary Air Injection (AIR) pump motor -V101- does not start up in intervals

Check secondary air pump relay -J299-. Refer to Secondary Air Injection (AIR) pump relay -J299-, checking and activating .

Activating wastegate bypass regulator valve -N75

1. Press --> button.

Indicated on display

This solenoid valve is activated for 1 minute (clicks), unless --> button is pressed first to switch to the next actuator.

If valve is not activated (does not click)

Refer to 21 TURBOCHARGER, G-CHARGER

Activating Leak Detection Pump (LDP) -V144- (LDP for tank ventilation system)

1. Press --> button.

Indicated on display

The change-over valve in the LDP is activated for approximately 1 minute (clicks), unless --> button is pressed first to switch to the next actuator.

Note. The click can be heard by listening in the area of the front right (when looking in driving direction) wheelhousing.

If valve is not activated (does not click)

Refer to

1. «20 - FUEL PUMP, FUEL SUPPLY, EVAPORATIVE EMISSIONS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-generic-scan-tool-engine-codes-amu-bea-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO GENERIC SCAN TOOL ENGINE CODE(S): AMU, BEA, ATC, AWP
2. «20 - FUEL SUPPLY»(ref-276276-S39104821222008010300000) for 3.2 LITER V6 4V GENERIC SCAN TOOL, ENGINE CODE: BHE

Activating turbocharger boost pressure recirculation valve

1. Press --> button.

Indicated on display

This solenoid valve is activated for 1 minute (clicks), unless --> button is pressed first to switch to the next actuator.

If valve is not activated (does not click)

Refer to 21 TURBOCHARGER, G-CHARGER

Checking Evaporative Emission (EVAP) Canister Purge Regulator Valve -N115

1. Press --> button.

Note. This solenoid valve is located at the EVAP canister below spare tire well at rear of vehicle under a cover; accessible after raising vehicle.

Indicated on display

This solenoid valve is activated for 1 minute (clicks), unless --> button is pressed first to switch to the next actuator.

If valve is not activated (does not click)

1. Check Evaporative Emission (EVAP) Canister Purge Regulator Valve -N115

Refer to

1. «20 - FUEL PUMP, FUEL SUPPLY, EVAPORATIVE EMISSIONS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-generic-scan-tool-engine-codes-amu-bea-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO GENERIC SCAN TOOL ENGINE CODE(S): AMU, BEA, ATC, AWP
2. «20 - FUEL SUPPLY»(ref-276276-S39104821222008010300000) for 3.2 LITER V6 4V GENERIC SCAN TOOL, ENGINE CODE: BHE

Activating fuel injectors

Note. Fuel injectors are activated in ignition sequence, i.e. cyl. 1, cyl. 3, cyl. 4, cyl. 2.

1. Press --> button.

Indicated on display

1. Press --> button.

Indicated on display

After pressing arrow button, injector must click five times.

If injector does not click

1. Check fuel injectors. Refer to «Fuel injectors, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. Press --> button.

Indicated on display

1. Press --> button.

Indicated on display

After pressing arrow button, injector must click five times.

If injector does not click

1. Check fuel injectors. Refer to «Fuel injectors, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. Press --> button.

Indicated on display

1. Press --> button.

Indicated on display

After pressing arrow button, injector must click five times.

If injector does not click

1. Check fuel injectors. Refer to «Fuel injectors, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. Press --> button.

Indicated on display

1. Press --> button.

Indicated on display

After pressing arrow button, injector must click five times.

If injector does not click

1. Check fuel injectors. Refer to «Fuel injectors, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. Press --> button.

Indicated on display

1. Press --> button.

Indicated on display (function selection)

Note. Output Diagnostic Test Mode (DTM) cannot be re-initiated until engine is started and ignition switched off and then on again.

Basic Setting

With ignition on and engine at standstill, the following operations can be performed using basic setting

1. Adaptation of throttle valve control module to ECM. Refer to «Throttle valve control module, adaptation»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__throttle-valve-control-module-adaptation)
2. Vehicles with automatic transmission: Adaptation of kick down function of accelerator pedal position sensor to ECM. Refer to Display group 63 (Refer to «Kick down function, learning»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__kick-down-function-learning) )

With ignition on and engine running, the following operations can be performed using basic setting

1. Adaptation of oxygen sensor control. Refer to «Checking oxygen sensor adaptation values and control»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__checking-oxygen-sensor-adaptation-values-and)
2. Troubleshooting via targeted activation and deactivation of oxygen sensor control. Refer to «Oxygen sensor and oxygen sensor control before catalytic converter, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__oxygen-sensor-and-oxygen-sensor-control)

Test requirements for operations with engine running

1. No DTCs in DTC memory.
2. Coolant Temperature less than 80° C
3. Electrical consumers switched off (radiator fan must NOT run during test).
4. A/C switched off.

Test sequence

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) . Engine must run at idle for this.
2. DTC memory checking and erasing. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
3. Let engine continue to run at idle.

When indicated on display

1. Press buttons "04" for the function "Basic Setting" and press Q button to confirm input.

When indicated on display

1. Input desired display group number.

Example

1. Press buttons "000" for "display group number 000" and press Q button to confirm input.

Note. After selecting display group number, the AKF valve is closed and A/C compressor switched off.

Indicated on display

Note. For display group number 000, measured values are displayed as a decimal. With printer switched on, current display can be printed out. To switch to a different display group, proceed as follows

1. If specified values are obtained in all display fields, press --> button.

Indicated on display (function selection)

Code Control Module

Note. Control module with part no. 8N0 906 018 C was equipped with "06500" as a permanent code and cannot be re-coded. Control module with part no. 8N0 906 018 K was equipped with "06550" as a permanent code and cannot be re-coded.

1. Connect VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Ignition must remain switched on for this.

When indicated on display

1. Press buttons "07" for the function "Code Control Module" and press Q button to confirm input.

When indicated on display

1. Input control module coding according to coding table. Refer to «Coding table»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__coding-table) .

Clarification of coding

Note. "TLEV. is an abbreviation and means: Transient Low Emission Vehicles

VAG1551 Scan Tool display indicates control module identification, e.g.

1. Press --> button.

Indicated on display (function selection)

Coding table

Note. "TLEV.is an abbreviation and means: Transient Low Emission Vehicles.

Read Measuring Value Block

Test conditions

1. Coolant temperature less than 80° C
2. Electrical consumers switched off (radiator fan must NOT run during test).
3. A/C switched off.

Test sequence

1. Connect VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Engine must run at idle for this.

When indicated on display

1. Press buttons "08" for the function "Read Measuring Value Block" and press Q button to confirm input.

When indicated on display

1. Input desired three digit display group number and press Q button to confirm input.

Note. Which display group should be chosen depends on current function and component tests.

Indicated on display for display group 000

Indicated on display (example) for display group 001

Note. With printer switched on, current display can be printed out on paper roll. To switch to a different display group, proceed as follows

Readiness code

The readiness code is an 8 digit display in measuring value block 086, display field 1. Each of the 8 digits is assigned to a specific exhaust related system.

If the function of these systems is checked via a test by On Board Diagnostic (OBD), which is successfully completed, then the position assigned to this system will be switched from "1" to "0". This occurs regardless of whether the test is indicated as "OK" or "not OK" as long as the test is successfully completed.

If a test is completed, but indicated as "not OK," a DTC will be stored in DTC memory. Check DTC Memory. Refer to Diagnostic Trouble Code (DTC) memory, checking and erasing .

When the readiness code is generated after a successfully completed test, "00000000" will be indicated.

Readiness code is reset to "11111111" if

1. DTC Memory was erased
2. Voltage supply to ECM was cut off (e.g. connector disconnected, battery disconnected)

In this case, readiness code must be re-generated. Refer to Readiness code, generating .

During driving operation in various load conditions, exhaust relevant tests are performed by the control module within a "short trip" and readiness code is generated on its own. In this case, however, concluding control possibilities are not available, meaning that it will not be indicated whether all positions of the readiness code are set to "0."

Readiness code, displaying

Test sequence

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Ignition must remain switched on for this.

When indicated on display

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

When indicated on display

1. Press buttons "086" for "display group number 086" and press Q button to confirm input.

When indicated on display

1. Check readiness code in display field 1

Specified value: 00000000

Significance of 8 digit number block for readiness code in display field 1

Note. Readiness code is not generated unless all indicated positions display a 0.

If specified value "00000000" is not obtained

1. Press --> button.

Indicated on display (function selection)

If specified value is not obtained

1. Generate readiness code. Refer to «Readiness code, generating»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__readiness-code-generating) .

Readiness code, generating

Special tools and shop equipment

Scheme 180

1. VAG1788/10 RPM adjuster

Requirements

1. Vehicle stationary
2. Electrical consumers switched off (radiator fan must NOT run during test).
3. Coolant Temperature less than 80° C

Procedure

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Work step 1: Check DTC Memory

1. Ignition switched on.

When indicated on display

1. Press buttons "02" for the function "Check DTC Memory" and press Q button to confirm input.

Number of stored DTCs or "No DTC recognized" will be indicated on display.

If a DTC is stored

1. Repair malfunction, erase DTC memory. Road test vehicle and then check DTC memory as a control measure.

If no DTCs are stored

1. Press --> button.

Work step 2: Erase DTC Memory

1. Ignition switched on.

When indicated on display

1. Press buttons "05" for the function "Erase DTC Memory" and press Q button to confirm input.

Note. When DTC memory is erased, readiness code is reset and must therefore be re-generated.

When indicated on display

1. Press --> button.

Work step 3: Adapt throttle valve control module to Engine Control Module (ECM)

1. Ignition switched on.

When indicated on display

1. Press buttons "04" for the function "Basic Setting" and press Q button to confirm input.

When indicated on display

1. Input "060" for "display group number 60" and press Q button to confirm input.

When indicated on display

1. Check readiness code in display field 3 and 4

If specified value "ADP OK" is obtained

1. Press -C- button.

Work step 3: Diagnostic of tank seal

1. Start engine.

Note. If necessary, ECM must be re-selected with the "address word" 01 following engine start, and the function "initiate basic setting" selected with "04."

Test requirements

1. Engine running at idle
2. Intake Air Temperature (IAT) less than 95° C (display group 4, display field 4)
3. Coolant Temperature less than 105° C (Display group 4, display field 3)

When indicated on display

1. Press buttons "04" for the function "Basic Setting" and press Q button to confirm input.

When indicated on display

1. Press buttons "071" for "display group number 071" and press Q button to confirm input.

When indicated on display

During test, "test on" will appear in display field 4. Maintain test requirements until a diagnostic result is displayed in display field 4.

1. Check the specified value in display field 4

Note. Test duration of tank seal lasts approx. 60 seconds.

Note. If indication in display field 4 jumps from "Test ON" to "Test OFF" during the test and display field 2 indicates "Aborted," repeat "Diagnostic of tank seal." During the repetition of the diagnostic, it can last up to approx. 60 seconds before indication in display field 4 switches from "Test OFF" to "Test ON."

If specified value "System OK" is obtained in display field 4

1. Press -C- button.

Work step 4: Diagnostic of tank ventilation valve

Test requirements

1. Engine running at idle
2. Coolant Temperature more than 80° C (Display group 4, display field 3)

When indicated on display

1. Press buttons "070" for "display group number 070" and press Q button to confirm input.

When indicated on display

1. Check the specified value in display field 4

Note. If test is not initiated or if indication switches from "Test ON" to "Test OFF," depress accelerator pedal briefly, test will be repeated.

1) Indication is only displayed if diagnostic result falls within specified range due to deviation of idle control and not due to deviation of an oxygen sensor (e.g. sensor 1 from EVAP canister). Otherwise field remains empty.

If specified value "TEV OK" is obtained

1. Press -C- button.

Work step 5: Diagnostic of fuel supply system

1. Engine running at idle
2. Oxygen sensor control active

When indicated on display

1. Input "107" for display group number "107" and press Q button to confirm input.

When indicated on display

1. Check the specified value in display field 4

1) Vehicles with Front Wheel Drive (FWD) and manual transmission

2) Vehicles with All Wheel Drive (AWD) and manual transmission

3) Vehicles with Front Wheel Drive (FWD) and automatic transmission

If specified value "System OK" is obtained

1. Press --> button.

Work step 6: Checking heated oxygen sensor

1. Engine running at 1800 - 2200 RPM

Note. Use VAG1788/10 RPM adjuster to achieve increased engine speed.

When indicated on display

1. Press buttons "08" for the function "Read measuring value block" and press Q button to confirm input.

When indicated on display

1. Input "041" for "display group number 041" and press Q button to confirm input.

When indicated on display

1. Check readiness code in display field 1 and 3

Note. Increasing engine speed accelerates the obtaining of specified values.

Important Notes to display fields 1 and 3

1. If oxygen sensors have not yet reached their operating temperature, there will be no indication in display fields 1 and 3, i.e. they will both be empty.
2. After reaching operating temperature of the two oxygen sensors, a resistance of less than 2kOhm must be indicated in display fields 1 and 3.
3. Do not continue test until a resistance of less than 2k Ohm is indicated in display fields 1 and 3.

1. Press --> button.

Work step 7: Diagnostic of operational readiness of oxygen sensors behind catalytic converter

1. Engine running at idle

When indicated on display

1. Press buttons "04" for the function "Basic Setting" and press Q button to confirm input.

When indicated on display

1. Input "036" for "display group number 036" and press Q button to confirm input.

When indicated on display

1. Check the specified value in display field 2

If specified value "B1-S2 OK" is obtained

1. Press -C- button.

Work step 8: Diagnostic of oxygen sensor aging before catalytic converter

Test requirements

1. In display group 041, display field 1 must indicate a resistance of less than 2k Ohm. Refer to «Work step 7: Diagnostic of operational readiness of oxygen sensors behind catalytic converter»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__work-step-7-diagnostic-of-operational) .
2. Engine running at 1800 - 2200 RPM

When indicated on display

1. Press buttons "034" for "display group number 034" and press Q button to confirm input.

When indicated on display

1. Check the specified value in display field 4

If specified value "B1-S1 OK" is obtained

1. Press -C- button.

Work step 9: Diagnostic oxygen sensor control system

1. Engine running at idle

When indicated on display

1. Input "037" for "display group number 037" and press Q button to confirm input.

When indicated on display

1. Check the specified value in display field 4

If specified value "System OK" is obtained

1. Press -C- button.

Work step 10: Diagnostic of oxygen sensor aging behind catalytic converter

1. Engine running at 1800 - 2200 RPM

When indicated on display

1. Press buttons "043" for "display group number 043" and press Q button to confirm input.

When indicated on display

1. Check the specified value in display field 4

If specified value "B1-S2 OK" is obtained

1. Press -C- button.

Work step 11: Diagnostic of catalytic converter

1. Engine continues to run at 1800 - 2200 RPM

When indicated on display

1. Press buttons "046" for "display group number 046" and press Q button to confirm input.

When indicated on display

1. Check the specified value in display field 4

Note. Test duration of catalytic converter diagnostic lasts approx. 60 seconds.

If specified value "Cat B1 OK" is obtained

1. Press --> button.

Work step 12: Readiness code, reading

1. Display readiness code. Refer to «Readiness code, displaying»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__readiness-code-displaying) .

To reduce the risk of personal injury and/or damage to the fuel injection and ignition systems, always observe the following

1. Always switch off ignition before disconnecting or connecting lines of the fuel injection and ignition system, including test leads.
2. If engine is to be cranked at starting RPM without starting (e.g. for compression testing), disconnect connectors from ignition coils and from fuel injectors.
3. It is possible that a control module will recognize a malfunction and store a DTC during some tests. After completing all tests and repairs, DTC memory should therefore be checked and erased if necessary.
4. Always switch ignition off before cleaning engine.

1. Always switch ignition off before disconnecting or connecting battery. Failure to do so may damage the Engine Control Module (ECM).

If special testing equipment is required during road test, note the following

Model specific WARNINGS continued..

Scan Tool (ST) and test equipment safety precautions, continued

Rules of cleanliness

When working on the fuel supply/injection system, pay careful attention to the following rules of cleanliness

1. Thoroughly clean all connections and the surrounding area before disconnecting.
2. Place parts that have been removed on a clean surface and cover. Do not use fluffy cloths!
3. Carefully cover over opened components or seal, if repairs are not carried out immediately.
4. Only install clean components: Only unpack replacement parts immediately prior to installation. Do not use parts that have been stored loose (in tool boxes etc.).

1. When the system is open: Do not work with compressed air if it can be avoided. Do not move vehicle unless absolutely necessary.
2. Disconnected electrical harness connectors must be protect from dirt and moisture
3. Make sure harness connectors are dry before connecting.

Scheme 181

1 - Leak Detection Pump (LDP) -V144

1. Below wheel housing, front, left

2 - Bank 1 sensor 1 (oxygen sensor before catalytic converter), with oxygen sensor heating; Bank 2 sensor 2 (oxygen sensor behind catalytic converter), with oxygen sensor heating

1. Both oxygen sensors and their related harness connectors are accessible from below after vehicle is raised
2. Component location of oxygen sensors. See «Oxygen sensors and protective cover»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)
3. Component location of harness connectors for oxygen sensors. See «Black and brown connectors»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)

3 - Camshaft Position (CMP) sensor 2 -G163

4 - Fuel injectors -N30 through N33

5 - Motronic Engine Control Module (ECM) -J220

6 - Ignition coils -N-, -N128-, -N158-, -N163

7 - Wastegate Bypass Regulator Valve -N75

1. Checking

Refer to 21 TURBOCHARGER, G-CHARGER

8 - Throttle Position (TP) sensor-G79- and sender -2- for accelerator pedal position -G185

1. Component location. See «Component locations of Throttle Position (TP) sensor -G79- and sender 2 for accelerator pedal position -G185»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)

9 - Brake light switch -F- and brake pedal switch -F47

1. Component location. See «Component location brake light switch -F- and brake pedal switch -F47»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)

10 - Clutch vacuum vent valve switch -F36

1. Component location. See «Component location, clutch vacuum vent valve switch -F36»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)

11 - Exhaust warning lamp -K83

1. Component location. See «Component location, exhaust warning lamp -K83»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

12 - Malfunction light for power accelerator activation -K132

1. "EPC" warning lamp
2. Component location. See «Component location, malfunction light for power accelerator activation -K132»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)

13 - Secondary Air Injection (AIR) pump relay -J299

1. Under a black, synthetic cover; directly behind Mass Air Flow (MAF) sensor

14 - Mass Air Flow (MAF) sensor -G70

15 - Engine Coolant Temperature (ECT) sensor -G62

16 - Fuel pressure regulator

17 - Speedometer Vehicle Speed Sensor (VSS) -G28

18 - Knock Sensor (KS) 2 -G66

19 - Turbocharger boost pressure recirculation valve -N249

20 - 3-pin harness connector

1. 3 pieces
2. Component location. See «Component location, 3-pin harness connectors»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)
3. For Knock Sensor (KS) 1 -G61
4. For Engine Speed (RPM) sensor -G28

1. For Knock Sensor (KS) 2 -G66

21 - Secondary Air Injection (AIR) solenoid valve -N112

22 - Knock Sensor (KS) 1 -G61

23 - Intake Air Temperature (IAT) sensor -G42

24 - Secondary Air Injection (AIR) pump motor -V101

1. Checking

Refer to 26 EXHAUST SYSTEM, EMISSION CONTROLS

25 - Pressure switch/power steering -F88

1. Component location. See «Component location, pressure switch/power steering -F88»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)

26 - Throttle valve control module -J338

1. With throttle drive (power accelerator actuation) -G186-, angle sensor -1- for throttle drive (power accelerator actuation) -G187- and angle sensor -2- for throttle drive (power accelerator actuation) -G188

27 - Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80

28 - Charge air pressure sensor -G31

1. Component location: Screwed in, above in charge air cooler
2. Checking

Refer to 21 TURBOCHARGER, G-CHARGER

1. Headlight must be removed in order to access charge air pressure sensor.

Refer to 94 LIGHTS, SWITCHES - EXTERIOR

Scheme 182

Item 1: Bank 1 sensor 1 (oxygen sensor before catalytic converter) with oxygen sensor heating

Item 2: Protective cover of oxygen sensor connector for both oxygen sensors

Item 3: Bank 1 sensor 2 (oxygen sensor behind catalytic converter) with oxygen sensor heating

4-pin harness connectors for both oxygen sensors and oxygen sensor heating are accessible at vehicle floor after unscrewing protective cover (arrows).

Scheme 183

Black connector: Harness connector for bank 1 sensor 1 (oxygen sensor before catalytic converter) and oxygen sensor heating

Brown connector: Harness connector for bank 1 sensor 2 (oxygen sensor behind catalytic converter) and oxygen sensor heating

Scheme 184

Scheme 185

Scheme 186

Scheme 187

Scheme 188

1 - For Knock Sensor (KS) 1 -G61

2 - For speedometer Vehicle Speed Sensor (VSS) -G28

3 - For Knock Sensor (KS) 2 -G66

Scheme 189

Scheme 190

1 - Seal

2 - Mass Air Flow (MAF) sensor -G70

3 - Phillips-head screw

4 - Air guide

5 - 5-pin harness connector

6 - Phillips-head screw

7 - Air filter, upper portion

8 - Filter element

9 - Nut -10 Nm

10 - Air intake connection

11 - Air filter, lower portion

12 - Hex-bolt (10 Nm)

Wire and component test using VAG1598/31 test box

Note. If the Engine Control Module (ECM) is equipped with a metal anti-theft housing (for theft prevention), the metal anti-theft housing must be removed from the ECM to connect the test box. Procedure. Refer to Engine Control Module (ECM) (with metal anti-theft housing), replacing . After repairs are complete, the metal anti-theft housing must be reinstalled. VAG1598/31 test box is designed so that it can be simultaneously connected to the wiring harness at the Engine Control Module (ECM) and also to the ECM itself. This is advantageous because electronic engine control remains fully functional (e.g. measurement of signals with engine running) when the test box is attached. Relevant test procedures note whether Engine Control Module (ECM) should also be connected to the test box or not. Always use VAG1594A connector test kit to attach measurement devices (e.g. VAG1527B voltage tester, VAG1526 multimeter etc.).

Special tools and equipment

Scheme 191

1. VAG1598/31

1. Switch ignition off.
2. Remove windshield wiper arms (unscrew).
3. Disconnect cover for plenum chamber and place it on windshield side.
4. Disengage locking lugs and remove control module connector.

Scheme 192

1. Connect VAG1598/31 test box to connector of wiring harness. Ground clip (arrow) at test box must be clipped to battery negative terminal. Relevant test procedures note whether Engine Control Module (ECM) should also be connected to the test box.
2. Perform test as described in relevant repair sequence.

Perform the following work after re-connecting Engine Control Module (ECM)

1. Check DTC memory and erase it if necessary. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. Generate readiness code. Refer to «Readiness code, generating»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__readiness-code-generating) .

All models

Note. In the first adaptation phase during engine Basic Setting, it is possible that the idle will be rough and vehicle may shake slightly in drive mode.

Procedure after voltage supply is interrupted

Note. In the first adaptation phase during engine Basic Setting, it is possible that the idle will be rough and vehicle may shake slightly in drive mode.

Special tools and shop equipment

Scheme 193

1. VAS5051 with VAG5051/1

or

1. VAG1551 with VAG1551/3B

Procedure

Perform the following steps after an interruption in the voltage supply.

1. Check DTC memory and erase it if necessary. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. Generate readiness code. Refer to «Readiness code, generating»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__readiness-code-generating) .

Engine Control Module (ECM) (without metal anti-theft housing), replacing

Removing ECMs with metal anti-theft housing. Refer to Engine Control Module (ECM) (with metal anti-theft housing), replacing .

Note. Adaptation values are erased when connector is disconnected from the Engine Control Module (ECM), DTC memory content remains intact.

Removing Engine Control Module (ECM)

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Ignition must remain switched on for this.

VAG1551 Scan Tool display indicates control module identification (example)

1. First (and always) allow display of control module identification and print it out. Refer to «Control module identification (example)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. Compare coding with coding versions. Refer to «Coding table»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__coding-table) .
3. Switch ignition off.
4. Remove windshield wiper arms (unscrew).

1. Disconnect cover for plenum chamber and place it on windshield side.

Scheme 194

1. Use a screwdriver to press locking lugs of bracket to the side and then remove Engine Control Module (ECM) toward front.
2. Disengage locking lugs and remove control module connector.

Installing Engine Control Module (ECM)

Installation is in reverse order of removal, noting the following

Note. In the first adaptation phase during engine Basic Setting, it is possible that idle will be rough and vehicle may shake slightly in drive mode.

1. Check DTC memory and erase it if necessary. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. Observe notes for coding new Engine Control Module (ECM). Refer to «Code Control Module»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
3. Perform adaptation of throttle valve control module -J338-. Refer to «Throttle valve control module, adaptation»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__throttle-valve-control-module-adaptation) .
4. For vehicles with automatic transmission, position of pedal value sensor for kick down must be learned. Refer to «Kick down function, learning»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__kick-down-function-learning) .

1. Cruise control must be switched off at ECM (if equipped - identify at steering column).

Refer to 01 ON BOARD DIAGNOSTIC (OBD)

1. Generate readiness code. Refer to «Readiness code, generating»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__readiness-code-generating) .

Engine Control Module (ECM) (with metal anti-theft housing), replacing

Removing ECMs without metal anti-theft housing. Refer to Engine Control Module (ECM) (without metal anti-theft housing), replacing .

Note. Adaptation values are erased when the harness connector is disconnected from the Engine Control Module (ECM), the DTC memory content remains intact.

Remove Engine Control Module (ECM)

Removing

1. Connect VAS5051 tester and select vehicle system "01 - Engine Electronics". Ignition must be switched on for this.

Scheme 195

VAS5051 tester display will indicate the control module identification and coding -2-.

1. Always allow display of control module identification first and print it out.
2. Switch ignition off.
3. Pry off both caps at wiper arms using a screwdriver.

Scheme 196

1. Loosen hex-nuts (arrows) several turns.
2. Loosen wiper arms -1- from wiper axle by lightly tilting.
3. Remove hex nuts completely and remove wiper arms.
4. Remove plenum chamber cover rubber seal -2-.

1. Remove plenum chamber cover -3- and place it on windshield side.

Note. Item -1- in illustration shows the Engine Control Module (ECM) with anti-theft housing.

Scheme 197

1. Use a screwdriver to press locking lug of bracket (arrow) to the side and then remove Engine Control Module (ECM) toward front.

Scheme 198

To restrict accessibility (for theft prevention) to the harness connectors and Engine Control Module (ECM), the Engine Control Module (ECM) -1- is screwed to a metal anti-theft housing -4- via a locking mechanism -2- and snap-off screws -3-.

The threads of the snap-off screws are coated with locking compound to make it more difficult to remove the snap-off screws.

To disconnect the harness connectors from the Engine Control Module (ECM) (e.g. when connecting a test box or when replacing the ECM), the ECM must be removed from the metal anti-theft housing. This procedure is described as follows.

The following equipment is required

Scheme 199

1. Heat gun -1- (from VAS1978 Wiring Harness Repair Kit)
2. Adapter nozzle -2- (also from VAS1978 Wiring Harness Repair Kit)
3. Standard locking pliers

Procedure

1. "Flip" the Engine Control Module (ECM) with anti-theft housing in direction of the engine compartment so that the locking mechanism (item -2- in illustration) becomes visible and place a clean rag below the Engine Control Module (ECM) with anti-theft housing.

Scheme 200

1. Adjust the heat gun as shown in illustration, i.e. temperature adjustment -2- to maximum heat output and the two-stage switch for air mass -3- to position 3.

Note. Next, use the heat gun to heat the threads of the locking mechanism in which the snap-off screws are screwed into. This step loosens the locking compound on the threads of the snap-off screws for easier removal.

Scheme 201

1. Guide nozzle -1- of heat gun to the locking mechanism threads so that the nozzle "encloses" the threads. It is OK to let the nozzle make contact at the upper end of the metal anti-theft housing.
2. Switch on heat gun and heat up thread for approx. 20 to 25 seconds.

Scheme 202

1. Next, using locking pliers -1-, grab screw head -2- and remove snap-off screw by turning in direction of arrow.

The procedure for the second snap-off screw is exactly the same. Be very careful since the control module connector is in close proximity.

Scheme 203

1. Guide nozzle -1- of the heat gun to the locking mechanism threads again so that the nozzle "encloses" the threads. It is OK to let the nozzle make contact at the upper end of the metal anti-theft housing.
2. Switch on heat gun and heat up threads for approx. 20 to 25 seconds.

Scheme 204

1. Next, using locking pliers -1-, grab screw head -2- and remove snap-off screw by turning in direction of arrow.

The Engine Control Module (ECM) can now be removed from the metal anti-theft housing.

1. Disengage connectors from Engine Control Module (ECM) and then disconnect connectors.
2. Remove old Engine Control Module (ECM) and insert new one.

Installing Engine Control Module (ECM)

Installation is the reverse order of removal, noting the following

After repairs are complete, the metal anti-theft housing must be reinstalled. Use new snap-off screws.

1. Bend back locking lug of bracket.

After installing a new Engine Control Module (ECM), the following work steps must be performed

1. Activate Engine Control Module (ECM) in "Guided Troubleshooting" below subject heading "Engine Control Module (ECM), replacing".

Use VAS5051 tester to do so.

Idle speed, checking

Special tools and equipment

1. VAS5051 with VAG5051/1

or

1. VAG1551 with VAG1551/3B

Test conditions

1. Exhaust system free of leaks
2. Engine coolant temperature less than 80° C
3. Electrical consumers switched off (radiator fan must NOT run during test)
4. A/C switched off

1. Pressure gauge not connected
2. Vehicles with automatic transmission: selector lever in P or N

Note. Idle speed cannot be adjusted. Idle speed is checked during Basic Setting of the engine. During Basic Setting, the Evaporative Emission (EVAP) canister purge regulator valve (EVAP valve -N80-) is closed and the A/C compressor is switched off

Test sequence

1. Check DTC memory. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) . There must not be any DTCs stored, repair malfunctions if necessary, erase DTC memory, switch engine off and start again, road test vehicle and check DTC memory again as a control measure.
2. Let engine continue to run at idle.

When indicated on display

1. Press buttons -0- and -4- to select "Basic Setting" and press -Q- button to confirm input.

When indicated on display

1. Press buttons -0-, -5- and -6- to select "display group number 056" and press -Q- button to confirm input.

Indicated on display

1. Check whether engine speed in display field 1 (actual engine speed) is within permitted tolerance range.

1) Vehicles with Front Wheel Drive (FWD) and manual transmission

2) Vehicles with All Wheel Drive (AWD) and manual transmission

3) Vehicles with Front Wheel Drive (FWD) and automatic transmission

Note. Engine speed in display field 1 (actual engine speed) is the current engine speed. Engine speed in display field 2 (specified engine speed) is a theoretical engine speed calculated by the ECM. At idle, the ECM always attempts to adapt the engine speed (actual) to the specified engine speed (specified). This means that the engine speed (actual) must always approximately match the engine speed (specified) at idle. Display fields 3 and 4 provide information, but are not relevant for checking idle speed.

If specified value is obtained

1. Press --> button.

Indicated on display (function selection)

If specified value is not obtained

1. Check DTC memory again. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. If DTC memory was erased, readiness code must be re-generated. Refer to «Readiness code, generating»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__readiness-code-generating) .

If idle speed is too high or low and there are no DTCs in DTC memory, the following tests (marked with diamonds) must be performed

1. Un-metered air in intake air system, checking. Refer to «Intake air system, checking for leaks (un-metered air)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__intake-air-system-checking-for-leaks)
2. Check throttle valve control module. Refer to «Throttle valve control module -J338-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__throttle-valve-control-module-j338-checking)
3. Evaporative Emission (EVAP) canister purge regulator valve always open, checking. Refer to «Evaporative Emission (EVAP) canister purge regulator valve -N80-, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__evaporative-emission-evap-canister-purge-regulator)
4. Perform adaptation of throttle valve control module. Refer to «Throttle valve control module, adaptation»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__throttle-valve-control-module-adaptation)

Significance of 5 digit display of display group 056

System pressure, fuel pressure regulator and residual pressure, checking

Special tools and equipment

Scheme 205

1. VAG1318
2. VAG1318/7

Scheme 206

1. VAG1318/17 (2x)

Note. Fuel pressure regulator regulates fuel pressure according to intake manifold pressure. This ensures that the pressure drop at the fuel injectors remains the same for each speed and load range of the engine.

Test conditions

1. Fuel Pump (FP) OK, checking. Refer to «Fuel Pump (FP) relay -J17-, checking activation»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)
2. Fuel Pump (FP) OK, checking

Refer to

1. «20 - FUEL PUMP, FUEL SUPPLY, EVAPORATIVE EMISSIONS»(/audi/tt/8n-1998-2003/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-generic-scan-tool-engine-codes-amu-bea-atc-awp) for 1.8 LITER 4-CYL. 5V TURBO GENERIC SCAN TOOL ENGINE CODE(S): AMU, BEA, ATC, AWP
2. «20 - FUEL SUPPLY»(ref-276276-S39104821222008010300000) for 3.2 LITER V6 4V GENERIC SCAN TOOL, ENGINE CODE: BHE

1. Fuel filter OK
2. Battery voltage at least 11 V

Checking system pressure

1. Open fuel filler flap briefly (release pressure).

Scheme 207

1. Remove fuel supply hose -1- (with white marking) from supply line.

Scheme 208

1. Connect VAG1318 using adapters 1318/7 and 1318/17 (2 pieces) at supply line.
2. Open valve of pressure gauge. Lever points in direction of flow.
3. Start engine and let run at idle.
4. Measure fuel pressure.

1. Specified value: approx. 2.5 bar positive pressure

Scheme 209

1. Disconnect vacuum hose at fuel pressure regulator.

1. Fuel pressure must rise to approx. 3.0 bar positive pressure.

1. Switch ignition off.
2. Check for proper seal and residual pressure by observing pressure drop on pressure gauge.

1. After 10 minutes, there must be at least 1.5 bar positive pressure

If residual pressure sinks below 1.5 bar positive pressure

1. Start engine and let run at idle.

Scheme 210

1. Switch ignition off after pressure has built up. Simultaneously close valve of VAG1318 pressure gauge (lever perpendicular to direction of flow -arrow-).
2. Observe pressure drop on pressure gauge.

If pressure does not drop now

1. Check check-valve of Fuel Pump (FP).

If pressure drops again

1. Open valve of VAG1318 pressure gauge (lever in direction of flow).
2. Start engine and let run at idle.
3. Switch ignition off after pressure has built up. Simultaneously clamp return line (with blue marking) fully closed (sealed).

If pressure does not drop now

1. Replace fuel pressure regulator

If pressure drops again

1. Check wire connections, O-rings at fuel distributor and fuel injectors for proper seal.
2. Check pressure gauge for proper seal.

Note. Before disconnecting pressure gauge, release pressure by opening valve. Hold a container in front of connection for this.

Scheme 211

Special tools and equipment

1. VAG1526A
2. VAG1527B
3. VAG1594A
4. VAG1598/31

Checking internal resistance

1. Disconnect connector at the injector to be tested.

Scheme 212

1. Connect multimeter at valve for resistance measurement.

1. Specified value: 12 - 13 ohms (at room temperature)

If specified value is not obtained

1. Replace fuel injector. Refer to «Fuel injectors, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__fuel-injectors-removing-and-installing) .

If specified value is obtained

Checking voltage supply

Test conditions

1. Fuel Pump (FP) OK, checking. Refer to «Fuel Pump (FP) relay -J17-, checking activation»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)
2. Fuse for fuel injectors OK

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

1. Disconnect connector at the injector to be tested.

Scheme 213

1. Connect VAG1527B voltage tester as follows

1. Operate starter briefly (engine can also start).

1. LED must light.

If LED does not light

1. Check wire connection between terminals 1 and fuse for injector valves for open circuit.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

1. Repair open circuit if necessary.

If LED lights

1. Check activation of fuel injectors.

Checking activation

Test requirement

1. Internal resistance of injector OK

1. Slide back rubber grommet of fuel injector connector, but leave connector connected.

Scheme 214

1. Connect VAG1527B voltage tester between sockets 2 (signal) and 1 (B+).
2. Operate starter briefly (engine can also start).

1. LED must blink.

Note. Voltage testers do not go out completely between activations by the ECM, but rather continue to glow and then get slightly brighter during activation.

If LED does not blink

1. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .

1. Check the following wire connections for open circuit and short circuit to Ground and B+

1. Repair open circuit or short circuit if necessary.

If wire connection is OK

1. Replace Engine Control Module (ECM). Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__engine-control-module-ecm-without-metal) .

Scheme 215

1 - Fuel injector insert - 3 Nm

1. Use locking fluid D 000 600 A2 when installing

2 - O-Ring

1. Always replace

3 - Fuel injectors -N30 through N33

4 - Supply hose

5 - Return hose

6 - Fuel distributor

7 - Socket-head bolt - 10Nm

8 - Harness connector

1. For injectors
2. 4 pieces

9 - Fuel pressure regulator

10 - O-Ring

1. Always replace

11 - O-Ring

1. Always replace

12 - Retaining clip

13 - O-Ring

1. Always replace

14 - Retaining clip

1. Check for proper seating at fuel injector and fuel distributor

15 - Intake manifold

Fuel injectors, removing and installing

1. Disconnect wiring/connectors at

1. Fuel injectors -N30-, -N31-, -N32-, -N33
2. Intake Air Temperature (IAT) sensor -G42
3. Camshaft Position (CMP) sensor 2 -G163
4. Throttle valve control module -J338

1. Charge air pressure sensor -G31

1. Detach cable channel to fuel injectors.
2. Remove 2 socket-head bolts for fuel distributor.
3. Disconnect fuel supply and return lines at quick-release connection in front of right suspension strut.
4. Disconnect vacuum hose from fuel pressure regulator.

1. Place fuel distributor toward front.

1. Disengage retaining clip and remove fuel injector.

Note. Fuel lines must be disconnected before replacing fuel distributor.

Installation is in reverse order of removal, noting the following

1. O-rings at all opened connections. (Never remove plastic cap from valve head or replace front O-ring, pry O-ring off over plastic cap)
2. Lightly lubricate O-rings with clean engine oil
3. Make sure fuel injectors are in place and seated correctly
4. Check clip for unobstructed fitting

1. Place fuel distributor, with fuel injectors securely installed, on intake manifold and press in evenly

Tightening torque

Fuel distributor at intake manifold: 10 Nm

Scheme 216

Special tools and equipment

1. VAG1348/3-2
2. VAG1348/3A
3. VAG1594A
4. VAG1602

1. VAS5051 with VAG5051/1

or

1. VAG1551 with VAG1551/3B

Test requirement

1. Fuel pressure OK, checking. Refer to «System pressure, fuel pressure regulator and residual pressure, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__system-pressure-fuel-pressure-regulator-and)

Test sequence

1. Remove fuel distributor including fuel injectors from intake manifold. Refer to «Fuel injectors, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__fuel-injectors-removing-and-installing) . Fuel lines remain connected.
2. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .
3. Bridge terminals 1 and 65 at test box using adapter cables from VAG1594A connector test kit (this step supplies Ground to one side of relay coil of Fuel Pump -FP- relay).

Checking for proper seal

1. Turn ignition on.

Note. After switching ignition on, Fuel Pump (FP) will run continuously, even with engine not running. This is true because: Fuel Pump (FP) relay is supplied with B+ via central electronics after ignition is switched on. Fuel Pump (FP) relay Ground connection is via the cable bridge in test box.

1. Check to make sure fuel injectors are not leaking (visual check). With Fuel Pump (FP) running, only 1 - 2 drops per minute may drip out per injector.
2. If fuel loss is greater, stop Fuel Pump (FP) from running (End Output DTM) and replace malfunctioning fuel injector. Refer to «Fuel injectors, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__fuel-injectors-removing-and-installing) .

Checking injection quantity

1. Insert fuel injector to be tested in a measuring glass from VAG1602 injection quantity test device.

Scheme 217

1. Connect one terminal of fuel injector to engine Ground using an adapter cable and an alligator clip from VAG1594A connector test kit.
2. Connect the second terminal of fuel injector to B+ using VAG1348/3A remote control, VAG1348/3-2 adapter cable and assisting cable.
3. Switch ignition on.

1. Fuel Pump (FP) must run

1. Activate VAG1348/3A remote control for 30 seconds.
2. Perform measurement on all fuel injectors.
3. After all four fuel injectors have been activated, place measuring glasses on an even surface.

1. Specified value for each fuel injector: 145 ± 12 ml

1. If measured value of one or more fuel injectors is outside of specified range, switch Fuel Pump (FP) off (switch ignition off) and replace malfunctioning fuel injector. Refer to «Fuel injectors, removing and installing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__fuel-injectors-removing-and-installing) .

Note. Also check spray pattern when checking injection quantity. Spray pattern must be the same for all injectors.

1. Remove fuel injectors together with fuel distributor. Refer to «Installation is in reverse order of removal, noting the following»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__installation-is-in-reverse-order-of) .

Scheme 218

Special tools and equipment

1. VAG1526A
2. VAG1594A
3. VAG1598/31

Voltage is supplied to the Fuel Pump (FP) and several components of the injection system via the Fuel Pump (FP) relay -J17-.

For Fuel Pump (FP) relay -J17- to close, it is required that engine is turning. This means that the relay does not receive Ground (via ECM) until the ECM recognizes RPM signals.

Note. Fuel Pump (FP) relay is located at position 4 of micro-central electrics in driver's footwell, left.

Test requirement

1. Battery voltage at least 11 V

Function test of Fuel Pump (FP) relay

1. Remove driver-side storage compartment.

Refer to 68 - INTERIOR EQUIPMENT

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Ignition must remain switched on for this.

1. Initiate Output Diagnostic Test Mode. Refer to «Output Diagnostic Test Mode (DTM)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) and activate Evaporative Emission (EVAP) canister purge regulator valve -N80-.

Scheme 219

1. Fuel Pump (FP) relay (at position 4 of micro-central electrics in driver's footwell, left) must trigger and Fuel Pump (FP) must run

If relay does not trigger

1. Check activation of Fuel Pump (FP) relay.

If Fuel Pump (FP) does not run

1. Check voltage supply for Fuel Pump (FP) and components (via Fuel Pump -FP- relay). Refer to «Check voltage supply for Fuel Pump (FP) and components»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

Check activation of Fuel Pump (FP) relay

1. Switch ignition off.
2. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .
3. Connect socket 65 and socket 2 of test box to each other using wire from VAG1594 connector test kit.
4. Switch ignition on.

1. Fuel Pump (FP) relay (at position 4 of micro-central electrics in driver's footwell, left) must trigger

If relay triggers now, but didn't during output DTM

1. Replace Engine Control Module (ECM). Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__engine-control-module-ecm-without-metal) .

If relay does not trigger

1. Switch ignition off.
2. Remove Fuel Pump (FP) relay.

Scheme 220

1. Connect multimeter to terminal 19 of relay socket and Ground for voltage measurement.
2. Switch ignition on.

1. Specification: approx. battery voltage

If specified value is not obtained

1. Check wire connections.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

If specified value is obtained

1. Switch ignition off.

1. Check the following wire connection for open circuit and short circuit to Ground and B+

1. Repair open circuit or short circuit if necessary.
2. If wire connections are OK, replace Fuel Pump (FP) relay -J17-.

Scheme 221

1. Remove fuses S28, S32, S34 and S43 from fuse holder.
2. Initiate Output Diagnostic Test Mode. Refer to «Output Diagnostic Test Mode (DTM)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) and activate Evaporative Emission (EVAP) canister purge regulator valve -N80-.
3. Connect multimeter to Ground and to one terminal of the following fuses in fuse holder for voltage measurement.

If specified values are not obtained

1. Repeat test at another terminal of fuse socket.

If specified values are not obtained again

1. Check wire connections.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

1. If wire connections are OK, replace Fuel Pump (FP) relay -J17-.

Scheme 222

Special tools and equipment

1. VAG1526A
2. VAG1594A
3. VAG1598/31
4. VAS5051 with VAG5051/1

1. or

1. VAG1551 with VAG1551/3B

Test conditions

1. Coolant Temperature less than 80° C
2. Electrical consumers switched off (radiator fan must NOT run during test)
3. A/C switched off
4. Fuse for Mass Air Flow (MAF) sensor OK

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

Checking function

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Engine must run at idle for this.

When indicated on display

1. Press buttons -0- and -4- to select "Basic Setting" and press -Q- button to confirm input.

Note. During Basic Setting, the Evaporative Emission (EVAP) canister purge regulator valve (EVAP valve -N80-) is closed and the A/C compressor is switched off

When indicated on display

1. Press buttons -0-, -0- and -2- to select "display group number 002" and press -Q- button to confirm input.

Indicated on display

1. Check specified values for load detection.

If specified value is obtained

1. Press --> button.

Indicated on display (function selection)

Evaluation display group 002

Evaluation display group 002

Check voltage supply for Mass Air Flow (MAF) sensor

1. Disconnect connector at Mass Air Flow (MAF) sensor.

Scheme 223

1. Connect multimeter for voltage measurement as follows.

1. Operate starter briefly.

1. Specification: approx. battery voltage

Note. Voltage is supplied to Mass Air Flow (MAF) sensor via Fuel Pump (FP) relay.

If specified value is not obtained

1. Check wire connection from terminal 2 of connector to Fuel Pump (FP) relay via fuse for open circuit and short circuit to Ground

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

1. Repair open circuit or short circuit if necessary.

1. Connect multimeter to terminal 2 and terminal 3 of connector for voltage measurement.
2. Operate starter briefly.

1. Specification: approx. battery voltage

Note. Ground from the ECM is present at terminal 3 of connector.

If specified value is not obtained

1. Check wire connections. Refer to «Check wire connections for Mass Air Flow (MF) sensor»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__check-wire-connections-for-mass-air) .

1. Connect multimeter to terminal 3 and terminal 4 of connector for voltage measurement.
2. Switch ignition on.

1. Specification: approx. 5 V

If specified value is not obtained

1. Check wire connections. Refer to «Check wire connections for Mass Air Flow (MF) sensor»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__check-wire-connections-for-mass-air) .

Check wire connections for Mass Air Flow (MF) sensor

Note. Signal wire is also checked during wire test.

1. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .

1. Check the following wire connections for open circuit and short circuit to Ground and B+

1. Repair open circuit or short circuit if necessary.
2. Also check all wires for short circuit to each other.

If wire connection is OK

1. Replace Mass Air Flow (MAF) sensor -G70-.

Intake air system, checking for leaks (un-metered air)

Special tools and equipment

1. VAS5051 with VAG5051/1

or

1. VAG1551 with VAG1551/3B
2. Engine leak detection spray G 001 800 A1

Note. Leak detection spray is drawn into intake system along with un-metered air by vacuum in intake system. Leak detection spray decreases ignition quality and performance of the fuel mixture. This causes a reduction in engine speed and a sharp increase of CO content. Always observe the safety precautions printed on can.

Test sequence

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Engine must run at idle for this.

When indicated on display

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

When indicated on display

1. Press buttons -0-, -0- and -1- to select "display group number 001" and press -Q- button to confirm input.

Indicated on display: (1 - 4 = display fields)

1. Note engine speed in display field 1.
2. Systematically spray parts of intake system with engine leak detection spray.

If engine speed does not change

1. Press --> button.

Indicated on display (function selection)

If engine speed decreases

1. Press --> button.
2. Press buttons -0- and -6- to select "End output" and press -Q- button to confirm input.
3. Switch ignition off.
4. Check sprayed portions of intake system for leaks and repair malfunction.

Function of oxygen sensor control before catalytic converter

Note. Oxygen sensor compares oxygen content of air with residual oxygen content in exhaust and delivers a voltage signal to the control module. The voltage signal "mixture rich (too little residual oxygen)" is 0.7 - 1.1 V (relative to reference Ground). The voltage signal "mixture lean (too much residual oxygen)" is -0.1 to +0.3 V (relative to reference Ground). During transition from "rich" to "lean" and vice versa (lambda = 1.0) the voltage jumps from range of 0.7 to 1.1 V to range of -0.1 to +0.3 V or vice versa. Due to the steep voltage jump, oxygen sensor control cannot maintain the ideal mixture of lambda = 1.0 as constant. Oxygen sensor control constantly fluctuates back and forth between the conditions "slightly too lean" and "slightly too rich."

Note. If voltage change does not occur or occurs only slowly, the following malfunctions could be present

1. Slits or holes in sensor head clogged.
2. Sensors suffered thermal overload.
3. Transition resistance in signal wire or Ground wire.
4. Sensor too cold, sensor heating not functioning.

1. Sensor damaged by contact spray or similar substance (contact spray is drawn through the fine hollow interiors by thermal fluctuations and capillary action into the electrical wiring in sensor).
2. Sensor damaged by silicon fumes (The use of sealing materials containing silicon leads to traces of silicon to be drawn in by the engine. These traces are not combusted and damage the oxygen sensors).

Oxygen sensor and oxygen sensor control before catalytic converter, checking

Special tools and shop equipment

1. VAG1526A
2. VAG1594A
3. VAG1598/31
4. VAS5051 with VAG5051/1

1. or

1. VAG1551 with VAG1551/3B

Note. For the defined troubleshooting procedure, it is possible, to switch oxygen sensor control off by selecting display group 99 under "Basic Setting" and switch it on again under "Read Measuring Value Block." After selecting display group 99 (either in "Basic Setting" or "Read Measuring Value Block"), it is possible to switch back and forth between "Basic Setting" (function 04) and "Read Measuring Value Block" (function 08) by pressing buttons 4 or 8 on the VAG1551. Once function 04 "Basic Setting" is exited, oxygen sensor control is automatically switched on again. The 4-pin harness connectors for the oxygen sensor before catalytic converter (black) and for the oxygen sensor behind catalytic converter (brown) are located under a cover -2- at vehicle floor.

Test conditions

1. Road test performed and DTC memory erased
2. Coolant Temperature less than 80° C

Function test

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Engine must run at idle for this.

When indicated on display

1. Press buttons -0- and -4- to select "Basic Setting" and press -Q- button to confirm input.

Note. During Basic Setting, the Evaporative Emission (EVAP) canister purge regulator valve (EVAP valve -N80-) is closed and the A/C compressor is switched off

When indicated on display

1. Press buttons -0-, -3- and -0- to select "display group number 030" and press -Q- button to confirm input.

When indicated on display

1. Check oxygen sensor status in display field 1.

Note. "Oxygen sensor status" indicates status of oxygen sensor control and oxygen sensor.

Significance of 3 digit indication of display group 030

Note. The first field of the 3 digit indication (heating) fluctuates between 0 and 1.

Checking oxygen sensor adaptation values and control

1. Press -C- button.
2. Press buttons -0-, -3- and -2- to select "display group number 032" and press -Q- button to confirm input.

When indicated on display

1. Check oxygen sensor control in display fields 1 and 2.

1. Press -C- button.
2. Press buttons -0-, -3- and -3- to select "display group number 033" and press -Q- button to confirm input.

When indicated on display

1. Check oxygen sensor control in display fields 1 and 2.

Continuation

If specified value in display field 1 is not obtained or if value does not fluctuate at least 2 %

1. Road test vehicle in order to free oxygen sensor of possible residue and repeat test.

If specified value in display field 1 is not obtained even after road test or if value does not fluctuate at least 2 %

1. Check primary voltage. Refer to «Checking primary voltage»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__checking-primary-voltage) .
2. Check oxygen sensor heating. Refer to «Oxygen sensor heating for oxygen sensors before and after catalytic converter, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__oxygen-sensor-heating-for-oxygen-sensors) .
3. Check oxygen sensor before catalytic converter for aging. Refer to «Oxygen sensor aging, oxygen sensor before catalytic converter, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__oxygen-sensor-aging-oxygen-sensor-before) .

Evaluation display group 32 (1 Of 2)

Evaluation display group 32 (2 Of 2)

Evaluation display group 33

Checking primary voltage

1. Disconnect 4-pin harness connector (black) to oxygen sensor before catalytic converter.

Scheme 224

1. Connect multimeter between terminals 3 and 4 for voltage measurement.
2. Switch ignition on.

1. Specification: 0.400 - 0.500 V

1. Switch ignition off.

If specified value is not obtained

1. Check oxygen sensor wiring.

If specified value is obtained

1. Replace oxygen sensor before catalytic converter -G39-.

Checking oxygen sensor wiring

1. Disconnect 4-pin harness connector (black) to oxygen sensor before catalytic converter.
2. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .

1. Check the following wire connections for open circuit.

1. Repair open circuit if necessary.
2. Check wires for short circuit to each other.

If wire connection is OK

1. Replace Engine Control Module (ECM). Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__engine-control-module-ecm-without-metal) .

Oxygen sensor aging, oxygen sensor before catalytic converter, checking

Special tools and shop equipment

1. VAG1788/10 RPM adjuster

1. VAS5051 with VAG5051/1

or

1. VAG1551 with VAG1551/3B

Test requirement

1. Coolant temperature at least 80° C (Display group 4, display field 3)

Test sequence

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Engine must run at idle for this.

When indicated on display

1. Press buttons -0- and -4- to select "Basic Setting" and press -Q- button to confirm input.

When indicated on display

1. Press buttons -0-, -3- and -4- to select "display group number 034" and press -Q- button to confirm input.

When indicated on display

1. Adjust engine speed using VAG1788/10 to 1800 - 2200 RPM.
2. Continue test as soon as display 4 indicates "Test ON."

Note. This process can take a few minutes.

Note for display field 2

Calculated value from engine speed and engine load.

Note for display field 3 and 4

Period duration is the time between two oxygen sensor voltage jumps (e.g. rich - lean - rich) and is therefore a measurement of the aging condition of the oxygen sensor. If the specified time is exceeded, display field 4 will indicate = B1-S1 not OK.

If specified value in display field 3 and 4 is not obtained

1. Road test vehicle in order to free oxygen sensor of possible residue and repeat test.

If specified value in display field 3 and 4 is not obtained, even after road test

1. Replace oxygen sensor before catalytic converter -G39-.

Oxygen sensor and oxygen sensor control behind catalytic converter, checking

Note. Oxygen sensor control behind the catalytic converter is responsible for final control correction. It is the primary sensor and can override the signal from the oxygen sensor control before the catalytic converter. It corrects slight changes in the mixture (i.e. enrichment) via the oxygen sensor before catalytic converter by holding the oxygen sensor control before catalytic converter at its higher or lower limit for a specific time (duration). If this time is in the positive range (i.e. 50 ms), mixture is shifted in the -enrich- direction. If this time is in the negative range (i.e. -50 ms), mixture is shifted in the -lean- direction.

The 4-pin harness connector (brown) for the oxygen sensor behind catalytic and oxygen sensor heating is located under a cover at vehicle floor.

Scheme 225

Special tools and shop equipment

1. VAG1526A
2. VAG1594A
3. VAG1598/31
4. VAG1788/10 RPM adjuster

1. VAS5051 with VAG5051/1

or

1. VAG1551 with VAG1551/3B

Test conditions

1. Road test performed and DTC memory erased.
2. Coolant Temperature less than 80° C

Test sequence

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Engine must run at idle for this.

When indicated on display

1. Press buttons -0- and -4- to select "Basic Setting" and press -Q- button to confirm input.

Note. During Basic Setting, the Evaporative Emission (EVAP) canister purge regulator valve (EVAP valve -N80-) is closed and the A/C compressor is switched off

When indicated on display

1. Press buttons -0-, -3- and -4- to select "display group number 034" and press -Q- button to confirm input.

When indicated on display

1. Adjust engine speed using VAG1788/10 to 2800 - 3200 RPM.
2. Continue test as soon as display field 2 indicates an exhaust temperature of more than 350° C.

Note. This process can take a few minutes.

1. Press -C- button.
2. Adjust engine speed using VAG1788/10 to 1800 - 2200 RPM.

When indicated on display

1. Press buttons -0-, -3- and -0- to select "display group number 030" and press -Q- button to confirm input.

When indicated on display

1. Check oxygen sensor status for oxygen sensor behind catalytic converter in display field 2.

Note. "Oxygen sensor status" indicates status of oxygen sensor control and oxygen sensor.

Significance of 3 digit indication of display group 030

Note. Oxygen sensor control of oxygen sensor behind catalytic converter (B1-S2) is not active without engine load. The first position of the 3 digit indication (heating) fluctuates between 0 and 1.

Checking oxygen sensor control behind catalytic converter

1. Press -C- button.

When indicated on display

1. Press buttons -0-, -3- and -7- to select "display group number 037" and press -Q- button to confirm input.

When indicated on display

1. Check oxygen sensor voltage in display field 2.
2. Check duration of oxygen sensor control before catalytic converter in display field 3 and diagnostic result in display field 4.

Note for display field 3

Oxygen sensor control behind catalytic converter is superior to oxygen sensor control before catalytic converter and is the primary control. It corrects slight changes in the mixture (i.e. enrichment or thinning) by holding the oxygen sensor control before catalytic converter at its higher or lower point for a specific time (duration). If this time is in the positive range (i.e. 50 ms), mixture is shifted in the -enrich- direction. If this time is in the negative range (i.e. 50 ms), mixture is shifted in the -lean- direction.

Evaluation display group 37

Continuation

If specified value in display field 3 and 4 is not obtained

1. Road test vehicle in order to free oxygen sensor of possible residue and repeat test.

If specified value in display field 3 and 4 is not obtained, even after road test

1. Replace oxygen sensor before catalytic converter -G39-.

Note. If oxygen sensor voltage is OK and duration of oxygen sensor behind catalytic converter is still above 1200 ms even after a road test, this indicates an aged oxygen sensor before catalytic converter.

1. Disconnect 4-pin harness connector (brown) to oxygen sensor behind catalytic converter.

1. Connect multimeter between terminals 3 and 4 for voltage measurement.
2. Switch ignition on.

1. Specification: 0.400 - 0.500 V

1. Switch ignition off.

If specified value is not obtained

1. Check oxygen sensor wiring.

If specified value is obtained

1. Replace oxygen sensor behind catalytic converter

1. Disconnect 4-pin harness connector (brown) to oxygen sensor behind catalytic converter.
2. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .

1. Check the following wire connections for open circuit.

1. Repair open circuit if necessary.
2. Check wires for short circuit to each other.

If wire connection is OK

1. Replace Engine Control Module (ECM). Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__engine-control-module-ecm-without-metal) .

Oxygen sensor heating for oxygen sensors before and after catalytic converter, checking

Special tools and shop equipment

1. VAG1526A
2. VAG1594A
3. VAG1598/31

Test conditions

1. Coolant Temperature less than 80° C
2. Fuse for oxygen sensor heating OK

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

Test sequence

1. Disconnect 4-pin harness connector (black) to oxygen sensor before catalytic converter, or
2. Disconnect 4-pin harness connector (brown) to oxygen sensor behind catalytic converter.

Scheme 226

1. Connect multimeter between terminals 1 and 2 of relevant connector for resistance measurement.

1. Specified value at room temperature: 1 - 5 ohms

Note. At higher temperatures, resistance climbs sharply.

If specified value is not obtained

1. Replace oxygen sensor.

If specified value is met

1. Check voltage supply of oxygen sensor heating. Refer to «Checking voltage supply of oxygen sensor heating»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__checking-voltage-supply-of-oxygen-sensor) .

Checking voltage supply of oxygen sensor heating

1. Connect multimeter between terminals 1 (B+) and 2 (Ground) for voltage measurement.
2. Start engine.

1. Specification: approx. battery voltage, possibly fluctuating

Note. At certain operating points, the ECM "pulses" the Ground for oxygen sensor heating. This means that the Ground is switched on and off at these points. It is therefore possible that the voltage displayed on the tester will fluctuate. The ECM switching oxygen sensor heating on and off can be observed, if necessary, in the function "Read Measuring Value Block" display group number 041.

If there is no voltage

1. Connect multimeter for voltage measurement as follows

1. Operate starter briefly.

1. Specification: approx. battery voltage

If there is no voltage again

1. Check wire connection from terminal 1 of connector to Fuel Pump (FP) relay via fuse for open circuit

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

If voltage supply is OK

1. Connect multimeter for voltage measurement as follows

1. Start engine.

1. Specification: approx. battery voltage, possibly fluctuating

1. Switch ignition off.

If there is no voltage

1. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .

1. Check the following wire connection for open circuit

Oxygen sensor heating for oxygen sensor before catalytic converter (black connector)

Oxygen sensor heating for oxygen sensor behind catalytic converter (brown connector)

1. Repair open circuit if necessary.

If wire connection is OK, but there is no Ground supply for oxygen sensor heating

1. Replace Engine Control Module (ECM). Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__engine-control-module-ecm-without-metal) .

Oxygen sensor, removing and installing

Special tools and equipment

Scheme 227

1. 3337/9 socket wrench insert SW16
2. Locking fluid G 052 112 A3

Procedure

1. Disconnect 4-pin harness connector of relevant oxygen sensor and lay it to side.

Note. Identification of oxygen sensor before catalytic converter: black connector. Identification of oxygen sensor behind catalytic converter: brown connector.

1. Unscrew oxygen sensor using special tool 3337/9.

Note the following when installing

Note. Oxygen sensor wiring must always be secured in the same position when installing so that contact with the exhaust pipe is avoided. Oxygen sensor threads are coated with an assembly paste. This paste must not contact sensor openings. Tightening torque: 55 Nm

Scheme 228

The secondary air system results in quicker heating and therefore earlier operating readiness of the catalytic converter following cold start.

Principle

Due to over-enrichment of the mixture during the cold start phase, there is an increased amount of un-combusted carbon monoxide in the exhaust. Secondary Air Injection (AIR) improves secondary oxidation in the catalytic converter and therefore reduces emissions. The heat produced by secondary oxidation greatly reduces start-up time for the catalytic converter, therefore improving exhaust quality during the cold start phase significantly.

Function

1. In the cold start phase, the ECM - «Secondary Air Injection (AIR) valve, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) activates the secondary air pump - «Secondary Air Injection (AIR) valve, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) via the relay for secondary air pump -1-. Air reaches the combination valve for Secondary Air Injection (AIR) - «Secondary Air Injection (AIR) valve, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .
2. Parallel to this, the Secondary Air Injection (AIR) solenoid valve - «Secondary Air Injection (AIR) valve, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) is activated, which permits negative pressure to reach the combination valve for Secondary Air Injection (AIR) - «Secondary Air Injection (AIR) valve, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) and the pressure unit for boost pressure regulation - «Secondary Air Injection (AIR) valve, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) . The combination valve for Secondary Air Injection (AIR) thereby opens the path for secondary air to the exhaust channels of the cylinder head.

1. To prevent unnecessary torque loss, secondary air is led around the turbocharger -8-. For this, the boost pressure regulation pressure unit opens the boost pressure valve. The pressure unit, designed as a double reservoir, has a vacuum connection for this on the low pressure side.

1 - Secondary Air Injection (AIR) pump relay -J299

2 - Motronic Engine Control Module (ECM) -J220

3 - Secondary Air Injection (AIR) solenoid valve -N112

4 - Intake manifold

5 - Check-valve

1. Installed position (light/dark half): Arrow points in direction of flow, as shown in

6 - Vacuum reservoir

7 - Pressure unit for boost pressure regulation

8 - Turbocharger

9 - Cylinder head

10 - Combination valve for Secondary Air Injection (AIR)

11 - Air filter

12 - Secondary Air Injection (AIR) pump motor -V101

Scheme 229

Special tools and shop equipment

1. VAG1526A
2. VAG1527B
3. VAG1594A
4. VAG1598/31

1. VAS5051 tester

or

1. VAG1551 with VAG1551/3B

Component location. Refer to Component locations, overview .

Test requirement

1. Perform Output Diagnostic Test Mode

Checking internal resistance

1. Unbolt bracket for Secondary Air Injection (AIR) solenoid valve from intake manifold.
2. Disconnect harness connector from Secondary Air Injection (AIR) valve -N112-.

Scheme 230

1. Connect multimeter at valve for resistance measurement.

1. Specified value: 25 - 35 ohms

1. If specified value is not obtained, replace Secondary Air Injection (AIR) solenoid valve -N112-.

Checking voltage supply

1. Disconnect harness connector from Secondary Air Injection (AIR) valve -N112-.

Scheme 231

1. Connect VAG1527B voltage tester as follows

1. Operate starter briefly (engine can also start).

1. LED must light

If LED does not light

1. Perform the following tests (marked with diamonds)

Scheme 232

1. Fuse for Secondary Air Injection (AIR) solenoid valve

1. Check wire connection from terminal 1 of connector to Fuel Pump (FP) relay via fuse for open circuit

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

1. Check Fuel Pump (FP) relay. Refer to «Fuel Pump (FP) relay -J17-, checking activation»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)

Checking activation

1. Connect VAG1527B voltage tester as follows

1. Initiate Output Diagnostic Test Mode (DTM) and activate Secondary Air Injection (AIR) solenoid valve -N112-. Refer to «Output Diagnostic Test Mode (DTM)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

Indicated on display

1. LED must blink.

If LED does not blink or if it remains constantly lit

1. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .

1. Check the following wire connections for open circuit and short circuit to Ground and B+

1. Repair open circuit or short circuit if necessary.

If wire connection is OK

1. Replace Engine Control Module (ECM). Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__engine-control-module-ecm-without-metal) .

Secondary Air Injection (AIR) pump relay -J299-, checking and activating

Special tools and shop equipment

1. VAG1526A
2. VAG1527B
3. VAG1594A
4. VAG1598/31

Component location. Refer to Component locations, overview .

1. Initiate output Diagnostic Test Mode (DTM) and activate Secondary Air Injection (AIR) pump relay -J299-. Refer to «Output Diagnostic Test Mode (DTM)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

Scheme 233

1. Secondary Air Injection (AIR) pump relay -arrow- (under cover, left at bulkhead) must trigger and the Secondary Air Injection (AIR) pump motor -V101- must run.

A - If relay does not trigger

1. Check voltage supply of Secondary Air Injection (AIR) pump. Refer to «Checking voltage supply of Secondary Air Injection (AIR) pump relay»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__checking-voltage-supply-of-secondary-air) .
2. Check activation of Secondary Air Injection (AIR) pump relay. Refer to «Checking activation of Secondary Air Injection (AIR) pump relay»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__checking-activation-of-secondary-air-injection) .

B - If relay triggers, but Secondary Air Injection (AIR) pump does not run

1. Check voltage supply of Secondary Air Injection (AIR) pump motor. Refer to «Checking voltage supply for Secondary Air Injection (AIR) pump motor»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

Checking voltage supply of Secondary Air Injection (AIR) pump relay

1. Remove Secondary Air Injection (AIR) pump relay

Scheme 234

1. Connect multimeter for voltage measurement as follows.

1. Specification: approx. battery voltage

If specified value is not obtained

1. Perform the following tests marked with diamonds

Scheme 235

1. Check fuse S131 (50 A) in main fuse box/battery
2. Check wire connection from B+ (terminal 30) to fuse S131 for Secondary Air Injection (AIR) pump relay -J299- (below cover, left at bulkhead) for open circuit

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

1. Connect multimeter for voltage measurement as follows.

1. Operate starter briefly (engine can also start).

1. Specification: approx. battery voltage

If specified value is not obtained

1. Perform the following tests marked with diamonds

1. Check fuse S243 (in fuse holder, position 43)
2. Check wire connection from B+ (terminal 30) to fuse S131 for Secondary Air Injection (AIR) pump relay -J299- (below cover, left at bulkhead) for open circuit

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

Checking activation of Secondary Air Injection (AIR) pump relay

1. Switch ignition off.
2. Remove Secondary Air Injection (AIR) pump relay

1. Connect VAG1527B voltage tester as follows

1. Initiate Output Diagnostic Test Mode (DTM) and activate Secondary Air Injection (AIR) pump relay -J299-. Refer to «Output Diagnostic Test Mode (DTM)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

1. LED must blink.

If LED does not blink

1. Switch ignition off.
2. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .

1. Check the following wire connection for open circuit and short circuit to Ground and B+

1. Repair open circuit or short circuit if necessary.

If no malfunctions are detected

1. Replace Secondary Air Injection (AIR) pump relay -J299-.

Scheme 236

1. Remove center noise insulation (arrows).

Scheme 237

1. Remove connector for Secondary Air Injection (AIR) pump motor -V101-.
2. Connect VAG1527B voltage tester to connector terminals 1 and 2.
3. Initiate Output Diagnostic Test Mode (DTM) and activate Secondary Air Injection (AIR) pump relay -J299-. Refer to «Output Diagnostic Test Mode (DTM)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

1. LED must blink.

If LED does not blink

1. Perform the following tests marked with diamonds

1. Check wire connection from connector at Secondary Air Injection (AIR) pump motor -V101- to Secondary Air Injection (AIR) pump relay -J299- (in relay carrier below cover, left at bulkhead) for open circuit

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

1. Check wire connection from connector at Secondary Air Injection (AIR) pump motor -V101- to Ground point in engine compartment, left, for open circuit

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

If no malfunctions are detected

1. Replace Secondary Air Injection (AIR) pump motor -V101-.

Evaporative Emission (EVAP) canister purge regulator valve -N80-, checking

Special tools and equipment

1. VAG1526A
2. VAG1527B
3. VAG1594A
4. VAG1598/31

1. VAS5051 with VAG5051/1

1. or

1. VAG1551 with VAG1551/3B

Checking for proper seal

When there is no current, the Evaporative Emission (EVAP) canister purge regulator valve -N80- is closed.

1. Disconnect hoses from EVAP valve; harness connector remains connected.
2. Attach auxiliary hose to one connection of EVAP valve.
3. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .

Ignition must remain switched on for this.

1. Initiate output DTM and activate Evaporative Emission (EVAP) canister purge regulator valve -N80- (tank ventilation valve). Refer to «Output Diagnostic Test Mode (DTM)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

Indicated on display

Valve must click...

..and must open and close (can be tested by blowing into auxiliary hose).

If valve does not click

1. Check internal resistance of EVAP valve.

If valve does not open and close properly

1. Replace Evaporative Emission (EVAP) canister purge regulator valve -N80

Checking internal resistance

1. Disconnect connector at EVAP valve.

Scheme 238

1. Connect multimeter at valve for resistance measurement.

1. Specified value: 22 - 30 ohms

If specified value is not obtained

1. Replace Evaporative Emission (EVAP) canister purge regulator valve -N80-.

If specified value is obtained

1. Check voltage supply. Refer to «Checking voltage supply»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__checking-voltage-supply) .

Checking voltage supply

Note. Voltage is supplied to the EVAP valve via the Fuel Pump (FP) relay.

Test requirement

1. Fuse for the EVAP valve OK

1. Disconnect connector at EVAP valve.

1. Connect VAG1527B voltage tester as follows

1. Operate starter briefly.

1. LED must light.

If LED does not light

1. Check wire connection from terminal 1 to Fuel Pump (FP) relay via fuse for open circuit.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder

1. Repair open circuit if necessary.

If wire connection is OK

1. Check Fuel Pump (FP) relay. Refer to «Fuel Pump (FP) relay -J17-, checking activation»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

If LED lights

1. Checking activation.

Checking activation

1. Connect VAG1527B voltage tester to connector terminals 1 (B+) and 2.
2. Initiate output DTM and activate Evaporative Emission (EVAP) canister purge regulator valve -N80-. Refer to «Output Diagnostic Test Mode (DTM)»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc) .

1. LED must blink

If LED does not blink or if it remains constantly lit

1. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .

1. Check the following wire connection for open circuit and short circuit to Ground and B+

1. Repair open circuit or short circuit if necessary.

If wire connection is OK

1. Replace Engine Control Module (ECM). Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__engine-control-module-ecm-without-metal) .

E-Gas system, function

For E-Gas, the throttle valve is not operated by a cable from the accelerator pedal. There is no mechanical connection between the accelerator pedal and the throttle valve.

The position of the accelerator pedal is communicated to the Engine Control Module (ECM) via two sensors for accelerator pedal position (variable resistances; stored in one housing) that are connected with the accelerator pedal.

The accelerator pedal position (driver's intention) is a main input measure value for the ECM.

Operation of the throttle valve occurs via an electric motor (throttle valve actuator) in the throttle valve control module. This is true across the entire engine speed and engine load spectrum.

The throttle valve is operated by the throttle valve actuator according to the instructions of the ECM.

With ignition switched on and engine off, the ECM activates the throttle valve actuator precisely according to the sensor for accelerator pedal position. This means, if the accelerator pedal is depressed half way, the throttle valve actuator opens the throttle valve to the same degree; i.e. throttle valve would be opened half way.

With engine running (under load), the ECM can open or close the throttle valve independently of the sensor for accelerator pedal position.

This means, for example, that the throttle valve could be fully opened even though the accelerator pedal has only been depressed half way. This has the advantage of preventing torque losses at the throttle valve.

In addition to this, it results in significantly better values relative to emissions and consumption under certain load conditions.

The required engine torque can be achieved by the Engine Control Module (ECM) via the optimal combination of throttle valve diameter and boost pressure.

It would be incorrect to think that "E-Gas" consists of only one or two components. E-Gas is much more of a system containing all components that contribute to recognizing, controlling and monitoring the position of the throttle valve, e.g. sensor for accelerator pedal position, throttle valve control module, EPC warning lamp, Engine Control Module (ECM).

Electronic Power Control (EPC) warning lamp (malfunction indicator lamp for electronic accelerator-E-Gas) in instrument cluster, significance

Location of EPC warning lamp

Engine Control Module (ECM) checks all components that are important for function of the E-Gas system after ignition is switched on.

During the test of these components, the ECM switches the EPC warning lamp on.

If malfunctions are recognized in the E-Gas system during operation of the engine, the ECM switches on the EPC warning lamp in instrument cluster. (These malfunctions are listed in the DTC table). An entry is made in DTC memory at the same time.

Malfunction light for power accelerator activation -K132-, checking

Note. The malfunction light for power accelerator activation -K132- is also called the EPC warning lamp.

Special tools and equipment

Scheme 239

1. VAG1594A

1. VAG1598/31

Functional test of warning lamp

1. Switch ignition on.

1. EPC warning lamp must light up

A - malfunction light for power accelerator activation (EPC warning lamp) -K132- does not light up

1. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .
2. Bridge sockets 1 and 48 of test box.
3. Switch ignition on.

1. Warning lamp must light

If warning lamp does not light

1. Switch ignition off.
2. Remove instrument cluster and check bulb and its voltage supply

Refer to 90 INSTRUMENTS

If no malfunctions are detected

1. Check the following wire connection for open circuit and short circuit to B+

1. Repair open circuit or short circuit if necessary.

If wire connection is OK

1. Replace Engine Control Module (ECM). Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__engine-control-module-ecm-without-metal) .

B - malfunction light for power accelerator activation -K132- remains lit after engine start

1. Check DTC memory of Engine Control Module (ECM).

If no DTCs are stored

1. Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to «Wire and component test using VAG1598/31 test box»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__wire-and-component-test-using-vag159831) .
2. Check the following wire connection for short circuit to Ground

1. Repair short circuit if necessary.

If wire connection is OK

1. Replace Engine Control Module (ECM). Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__engine-control-module-ecm-without-metal) .

Throttle valve control module -J338-, checking

The following components are located in the housing for the throttle valve control module

1. Throttle drive (power accelerator actuation) -G186-. (This is an electric motor that is activated by the ECM. This electric motor opens the throttle valve against spring pressure.)
2. Angle sensor -1- for throttle drive (power accelerator actuation) -G187
3. Angle sensor -2- for throttle drive (power accelerator actuation) -G188

Note. The housing for the throttle valve control module must not be opened. The angle sensors are designed as potentiometers (variable resistances). They communicate the position of the throttle valve to the Engine Control Module (ECM) fully independent of each other. The potentiometers cannot be mechanically adjusted. Adjustments are made in Basic Setting (function 04) using the VAS5051 tester or VAG1551 Scan Tool.

Throttle valve control module, adaptation

During adaptation with ignition switched on and engine off, the Engine Control Module (ECM) learns the various positions of the throttle valve. These positions are stored in the control module. The return communication regarding the position of the throttle valve occurs via the two angle sensors for throttle drive.

An adaptation must always be performed when the throttle valve control module -J338- or the Engine Control Module (ECM) are removed and installed (or replaced) or if voltage supply to the Engine Control Module (ECM) is interrupted.

The learning process (adaptation) occurs

1. Via initiation of Basic Setting (function 04) display group 60 with ignition on.
2. Automatically if the ignition is switched on for at least 6 seconds without operating starter and accelerator pedal and the Engine Control Module (ECM) recognizes "adaptation required." (There will be no notification of whether adaptation was successful or not however). Adaptation required is recognized if stored voltage values from the angle sensors do not match actual measured voltage values within a certain tolerance range.

Note. Engine will not start during automatic adaptation.

Special tools and equipment

1. VAS5051 with VAG5051/1

or

1. VAG1551 with VAG1551/3B

Requirements

1. No DTCs in DTC memory; check DTC memory. Refer to «Diagnostic Trouble Code (DTC) memory, checking and erasing»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc)
2. Engine not running, ignition switched on
3. Accelerator pedal not depressed
4. Coolant Temperature more than 5° C but less than 100° C. (Read Measuring Value Block, display group 4, display field 3)

1. Intake Air Temperature (IAT) less than 100° C (Read Measuring Value Block, display group 4, display field 4)
2. Supply voltage for ECM larger than 11 V; checking. Refer to «Control module voltage supply, checking»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__control-module-voltage-supply-checking)

Procedure

1. Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Refer to «VAS5051 vehicle diagnostic, testing and information system or VAG1551 scan tool, connecting and selecting functions»(/audi/tt/8n-1998-2003/remont/fuel-system/#18l-4-cyl-5v-turbo-fuel-injection-ignition-engine-codes-atc__vas5051-vehicle-diagnostic-testing-and-information) .