Ignition/glow Plug System - 2.7l v6 Biturbo - Apb, Bel Audi A6 C5 рестайлинг

General notes on ignition system

1. Always switch off the ignition before connecting or disconnecting the battery, otherwise the engine control module may be damaged.
2. The engine control module is equipped with On Board Diagnostic (OBD).
3. For trouble -free operation of the electrical components a voltage of at least 11.5 V is necessary.
4. During some of the tests it is possible that the control module will detect and record a malfunction. The DTC memory must therefore be checked and if necessary erased when all tests and repair work have been completed.
5. After completing troubleshooting, repairs or component tests, it is possible that the engine will start, run for a short period and then cut out. If this happens it may be that the immobilizer is blocking the engine control module. In such cases the DTC memory must be checked and if necessary the control module must be adapted.

Safety precautions

To prevent injuries to persons and/or damage to the fuel injection and ignition system, the following must be noted

Technical data, ignition system

IGNITION SYSTEM TECHNICAL DATA

Ignition coils, checking

Note. The following procedure is for vehicles with engine code APB. The procedure for vehicles with engine code BEL is in IGNITION COILS, CHECKING, ENGINE CODE BEL . Misfiring is recognized by the On Board Diagnostic (OBD). This means a non -working cylinder is stored with the cylinder number in the DTC memory. This has an advantage in case of a malfunction the trouble shooting procedure can be started at a certain cylinder. Check the DTC memory of the Engine Control Module (ECM) before commencing trouble shooting.

Test conditions

1. No DTCs stored relating to any of the fuel injectors

Determine a non -working or misfiring cylinder as follows

1. With engine running disconnect harness connectors in sequence from fuel injectors, and observe engine performance. or
2. Compare spark plugs of all cylinders with each other and check for soot on electrodes.

When the faulty cylinder has been identified

1. Connect hand -held multimeter (resistance measurement) to spark plug connector

Note. The spark plug connector can be disconnected from the ignition coil.

Specification: approx.: 2k Ohm.

If specification is not obtained

1. Replace spark plug connector.

If specification is obtained

1. Exchange spark plug from faulty (misfiring) cylinder with one from another cylinder. Visually check spark plug for damage, e.g. cracks on ceramic body of spark plug.
2. If malfunction (misfire) occurs now on other cylinder, replace spark plug.

If the malfunction remains at the same cylinder

1. Exchange ignition coil from faulty (misfiring) cylinder with one from another cylinder. Visually check ignition coil for damage (ignition coil could be cracked or bursted)
2. If malfunction occurs now on other cylinder, replace ignition coil.

If malfunction remains at the same cylinder.

1. Disconnect harness connector from ignition coil.
2. Check Ground (GND) connection between socket 4a and engine Ground (GND) for open circuit and short circuit to B+. See appropriate System Wiring Diagrams article
3. Repair any open/short circuit as necessary.

If the Ground (GND) connection is OK.

1. Connect hand -held multimeter (voltage range) to terminal 15 of harness connector and Ground (GND).
2. Disconnect harness connector from fuel injector of cylinder to be tested.
3. Operate starter. Specification: approx. battery voltage

If the specification is not obtained

1. Check wiring. See appropriate System Wiring Diagrams article

If the specification is obtained

1. Disconnect 3-pin harness connectors on power output stages for ignition coils. See «COMPONENT LOCATIONS, OVERVIEW»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__component-locations-overview) .
2. Connect LED voltage tester to 3-pin connectors for both output stages.
3. Connect LED voltage tester VAG1527 to following contacts on connectors for power output stages

POWER OUTPUT STAGE 3-PIN HARNESS CONNECTOR CIRCUIT TEST (ENGINE CODE APB)

If the specifications are not obtained

Scheme 1

Scheme 2

1. Switch ignition off.
2. Check following wiring connections for open circuits and/or short to B+ or Ground (GND). POWER OUTPUT STAGE 3-PIN HARNESS CONNECTOR CIRCUIT TEST: OPENS/SHORTS (ENGINE CODE APB) Black 3-pin connector on power output stage, terminal 3-pin connector on ignition coil, terminal 1 1 (cylinder 1) 2 1 (cylinder 2) 3 1 (cylinder 3)
3. Check following wiring connections for open circuits and/or short to B+ or Ground (GND). IGNITION COIL 3-PIN HARNESS CONNECTOR CIRCUIT TEST: OPENS/SHORTS (ENGINE CODE APB) Brown 3-pin connector on power output stage, terminal 3-pin connector on ignition coil, terminal 1 1 (cylinder 4 2 1 (cylinder 5) 3 1 (cylinder 6)
4. Eliminate any open/short circuit as necessary.

Ignition coils, checking, Engine code BEL

Note. The ignition coil and the power output stage are integrated in one component.

Requirements

1. No DTCs stored relating to any of the fuel injectors

Determine a non -functional or misfiring cylinder as follows

1. Check misfire recognition. See «MISFIRE RECOGNITION, CHECKING»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel) .

If a misfire is recognized

1. Continue with cylinder displayed using test "If a misfire is recognized".

If no misfire is recognized

1. With engine running, disconnect connectors from injectors one at a time and observe how engine is running. or
2. Compare spark plugs of all cylinders with each other and look for corroded electrodes.

If the faulty cylinder is found

1. Exchange spark plug from faulty cylinder with one from another cylinder.

If problem cylinder moves with the spark plug

1. Replace spark plug.

If the fault remains with the cylinder

1. Exchange ignition coil from faulty cylinder with one from another cylinder.
2. If fault now appears in another cylinder, replace ignition coil.

If the fault remains with the cylinder

1. Check Ground wiring of ignition coil.

Checking Ground wiring of ignition coil

1. Disconnect 4-pin connector on respective ignition coil.
2. Check Ground wiring on socket 4 of 4 -pin connector after engine Ground for open circuit or short circuit to B+.
3. Eliminate any open or short circuits.

If Ground wiring is OK

1. Check voltage supply to ignition coil, see «CHECKING VOLTAGE SUPPLY OF THE IGNITION COILS»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel__checking-voltage-supply-of-the-ignition) .

Checking voltage supply of the ignition coils

1. Connect multimeter for measuring voltage to following sockets on connector
2. Switch ignition on. IGNITION COIL 4-PIN HARNESS CONNECTOR CIRCUIT TEST: VOLTAGE SUPPLY (ENGINE CODE BEL) 4-pin harness connector terminal Specification 1 + Ground (GND) Battery voltage

Specified value: approx. battery voltage

If the specified value is not attained

1. Check wiring connection for socket 1 via fuse to Motronic (ECM) power supply relay -J271- for continuity and repair if necessary. See appropriate System Wiring Diagrams article.
2. Check ECM power supply relay -J271-. See «MOTRONIC ECM POWER SUPPLY RELAY -J271 -, CHECKING»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel__motronic-ecm-power-supply-relay-j271) .

If the specification is not obtained

1. Check power output stage. See «POWER OUTPUT STAGES FOR IGNITION COILS, CHECKING»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel__power-output-stages-for-ignition-coils) .

Power output stages for ignition coils, checking

Note. The following procedure is for vehicles with engine code APB. The procedure for vehicles with engine code BEL is in POWER OUTPUT STAGES FOR IGNITION COILS, CHECKING, ENGINE CODE BEL . Power Output Stage -N122- (black connector) activates the ignition coils for cylinder bank 1 (cylinders 1 to 3). Power Output Stage 2 -N192- (brown connector) activates the ignition coils for cylinder bank 2 (cylinders 4 to 6).

Checking activation of power output stages

1. Disconnect harness connectors from all six fuel injectors. NOTE: It is important to ensure that no fuel is injected during the test as this would damage the catalytic converter. The harness connectors on the fuel injectors must therefore be disconnected.
2. Disconnect 4-pin harness connectors on power output stages. See «COMPONENT LOCATIONS, OVERVIEW»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__component-locations-overview) .
3. Connect LED voltage tester VAG1527 in turn to following contacts on two 4-pin connectors for power output stages.
4. Operate starter for a few seconds. POWER OUTPUT STAGE 4-PIN HARNESS CONNECTOR CIRCUIT TEST: ACTIVATION (ENGINE CODE APB) 6-pin connector on wiring harness, terminal Specification 1 + Ground (GND) LED voltage tester must flash (brief impulse) 3 + Ground (GND) 4 + Ground (GND)

If the specifications are not obtained

Scheme 3

1. Switch ignition off.
2. Connect test box VAG 1598/31 to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .
3. Check following wiring connections for open circuits and/or short to B+ or Ground (GND): POWER OUTPUT STAGE 4-PIN CONNECTORS AND VAG 1598/31 TEST BOX SOCKET (ENGINE CODE APB) Black 4-pin connector on wiring harness, terminal VAG1598/31 test box, socket 1 94 3 110 4 102 Brown 4-pin connector on wiring harness, terminal VAG1598/31 test box, socket 1 95 3 111 4 103
4. Correct any open/short circuit as necessary.

If no wiring malfunction is detected

1. Connect 4-pin connectors to power output stages.
2. Disconnect 3 -pin connectors from power output stages.
3. Connect LED voltage tester VAG1527 to battery (B+) and to one of 3 terminals on power output stage.
4. Operate starter for few seconds. LED voltage tester should flash.
5. Perform test with all 3 terminals on each of 3 -pin connectors for power output stages. LED voltage tester should flash each time.

If the LED voltage tester does not flash when testing one or more of the contacts

1. Check the Ground (GND) connections for the power output stages as follows: Disconnect 4 -pin connector from power output stages. Connect LED voltage tester VAG1527 to battery (B+) and terminal 2 of each 4 -pin connector in turn. LED voltage tester should light up.

If LED voltage tester does not light up

1. Test for open circuit in wiring using wiring diagram. See appropriate System Wiring Diagrams article.

If the LED voltage tester lights up

1. Replace power output stage.

Note. Before installing new power output stage coat metal side with heat paste (part no. G 052 170 A1). The heat paste is sed to prevent corrosion between the power output stage and the fastening point and to transfer heat from the power output stage.

Power output stages for ignition coils, checking, Engine code BEL

Note. The ignition coils and the power output stages are contained in one component

Scheme 4

1. Disconnect 4-pin connector for each ignition coil.
2. Check wiring connection from socket 2 of 4 -pin connector after body Ground for open circuit or short circuit to Ground.
3. Repair open or short circuit as necessary. See appropriate System Wiring Diagrams article.

If Ground wiring is OK

1. Check activation of power output stages. See «CHECKING ACTIVATION OF POWER OUTPUT STAGES»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel) .

1. Disconnect harness connectors from all six fuel injectors. NOTE: It is important to ensure that no fuel is injected during the test as this would damage the catalytic converter. The harness connectors on the fuel injectors must therefore be disconnected.
2. Disconnect 4-pin for each ignition coil.
3. Connect LED voltage tester V.A.G 1527 to following contacts on connectors for ignition coils.
4. Operate starter for a few seconds. IGNITION COIL 4-PIN HARNESS CONNECTOR CIRCUIT TEST: ACTIVATION (ENGINE CODE BEL) 4-pin connector on wiring harness, terminal Specification 3 + 2 LED voltage tester must flash (brief flash)

If the specified value is not attained

Scheme 5

1. Switch ignition off.
2. Connect test box V.A.G 1598/31 to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .
3. Check wiring connection from 4-pin connector on ignition coil and power output stages....
4. .....and to engine control module for open circuits and shorts circuits to B+ and Ground. IGNITION COIL 4-PIN HARNESS CONNECTOR CIRCUIT TEST: OPENS/SHORTS (ENGINE CODE BEL) 4-pin connector VAG1598/31 test box, socket Cyl. 1 102 Cyl. 2 110 Cyl. 3 94 Cyl. 4 103 Cyl. 5 111 Cyl. 6 95 Wire resistance: max. 1.5 Ohm
5. Repair any open circuits and short circuits. See appropriate System Wiring Diagrams article.

If there is no fault in the wiring

1. Replace ignition coil with power output stage.

Motronic ECM power supply relay -J271 -, checking

Location of relay: (Scheme 12)

Scheme 6

Note. The Motronic ECM power supply relay -J271- supplies the ignition coils with power output stages and also supplies the ECM on pin 3 and some other components with voltage. When the ignition is on, there must be 1 - 12 Volts on contact at the respective ignition coil.

Check activation wiring from power supply relay to ECM

1. Switch ignition on.
2. Remove Motronic ECM power supply relay -J271- from 3- position relay panel.
3. Connect V.A.G 1598/31 test box to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .
4. Check following wiring connections for open circuit or short circuit: POWER SUPPLY RELAY CIRCUIT TEST: ACTIVATION VAG1598/31 test box, socket Power supply relay terminal 23 4 See appropriate System Wiring Diagrams article. Wire resistance: max. 1.5 Ohm
5. Correct any open/short circuits as necessary. See appropriate System Wiring Diagrams article.

If no wiring fault is found

1. Check voltage supply for power supply relay. See «CHECKING VOLTAGE SUPPLY TO POWER SUPPLY RELAY»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel__checking-voltage-supply-to-power-supply) .

Checking voltage supply to power supply relay

1. Switch ignition off.
2. Connect multimeter for voltage measurement between terminal 1 on relay socket and Ground.
3. Connect multimeter for voltage measurement between terminal 2 on relay socket and Ground. Specified value: approx. battery voltage

If the specified value is not attained

1. Check voltage supply according to wiring diagram. See appropriate System Wiring Diagrams article.

If the specified value is attained

1. Check wiring connection between power supply relay and engine control module. See «CHECKING WIRING CONNECTION BETWEEN POWER SUPPLY RELAY AND ENGINE CONTROL MODULE»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel__checking-wiring-connection-between-power-supply) .

Checking wiring connection between power supply relay and engine control module

1. Check fuse. See appropriate System Wiring Diagrams article.

If no fault is found with fuse

1. Check following wiring connections for open circuit or short circuit: POWER SUPPLY RELAY CIRCUIT TEST VAG1598/31 test box, socket Power supply relay terminal 3 8 See appropriate System Wiring Diagrams article. Wire resistance: max. 1.5 Ohm
2. Correct open circuit or short circuit as necessary. See appropriate System Wiring Diagrams article.

If no fault is found in any of the tests

1. Replace Motronic ECM power supply relay -J271-.

Intake Air Temperature (IAT) sensor -G42-, checking

Location of sensor and connector, see COMPONENT LOCATIONS, OVERVIEW .

1. Connect vehicle diagnostic, testing and information system VAS 5051 or VAG1551 scan tool and select engine electronics control module by entering address word "01". See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051 OR VAG1551 SCAN TOOL, CONNECTING AND SELECTING FUNCTIONS»(/audi/a6/c5-2001-2004/remont/testing-diagnostics/#on-board-diagnostic-obd-27l-v6-biturbo-apb-bel) . Ignition must be switched on.

Indicated on display

Scheme 7

1. Press buttons -0- and -8- to select function "Read Measuring Value Block" and confirm entry with -Q- button.

Indicated on display

Scheme 8

1. Press buttons -0-, -0- and -4- to select "display group 004" and confirm entry with -Q- button.

Indicated on display (1...4 = display fields)

Scheme 9

1. Check display value for intake air temperature sensor (display field 4): DISPLAY GROUP 004: INTAKE AIR TEMPERATURE WITH ENGINE IDLING Display fields 1 2 3 4 Display Group 004: Intake air temperature with engine idling Display xxxx RPM xx.xxx V xxx.x °C xxx.x °C Indicates Engine speed Battery voltage Coolant temperature Intake air temperature Work range min.: 650 RPM min.:10.000 V min.: -48.0 °C min.: -48.0 °C max.: 6800 RPM max.: 15.000 V max.: 143.0 °C max.: 143.0 °C Specified value xxxx RPM 12.000...15.000 V 80.0...110.0 °C Between ambient temp. and 120 °C (1) (1) If there is a large difference between the temperature displayed and the ambient temperature at the sensor, check the sensor and sensor wiring for contact resistance and open circuit.

Checking wiring

1. Switch ignition off.
2. Connect test box VAG1598/31 to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .
3. Check for open circuit in wiring between test box and 2 pin harness connector using wiring diagram. Specification: max. 1.5 ohm IAT SENSOR CIRCUIT TEST Terminal on 2 -pin harness connector Contact on control module connector or test box 1 85 2 108
4. Check wiring for short circuits to each other between contacts 1 and 2 on 2-pin connector. Also test for short circuits to B+ or Ground (GND).

If no malfunction in wire is detected, go to CHECKING SENSOR .

Scheme 10

1. Measure resistance between contacts 1 (signal) and 2 (Ground) on connector for Intake Air Temperature (IAT) sensor -G42-. IAT SENSOR TEMPERATURE VERSUS RESISTANCE SPECIFICATIONS Temperature °C Resistance k ohm -20 approx. 13.8 0 approx. 5.5 20 approx. 2.4 40 approx. 1.1 60 approx. 0.6

If value does not match the specification

1. Replace intake air temperature sensor.

Note. In order to install the new sensor, the intake manifold must first be removed. See INTAKE MANIFOLD, REMOVING AND INSTALLING .

Engine speed (RPM) sensor -G28-, checking

Note. The engine speed sender is a combined speed sensor and reference mark sensor. Without a signal from the Engine Speed (RPM) sensor -G28- the engine cannot be started. If the signal from the Engine Speed (RPM) sensor -G28- fails while the engine is running, the engine will cut out immediately.

Checking Engine Speed (RPM) sensor

Component location of sensor and connector, see COMPONENT LOCATIONS, OVERVIEW .

1. Before performing test, make sure that sensor is correctly installed and firmly seated.
2. Disconnect harness connector for Engine Speed (RPM) sensor (gray connector).
3. Connect multimeter (Fluke 83 or equivalent) (resistance test range) to terminals 2 and 3 on connector for engine speed sensor using test lead from VAG1594 connector test kit. Specification: approx. 730 - 1000 Ohm

Note. The resistance value for the engine speed sensor is based on a temperature of 20 °C. The resistance increases as the temperature rises.

If the specification is not attained

1. Replace Engine Speed (RPM) sensor.

If the specification is attained

1. Connect multimeter (Fluke 83 or equivalent) (resistance test range) between terminals 2 and 1 (Ground) and between terminals 3 and 1 (Ground). Specification: infinite Ohms / open circuit in each test

If the specification is not attained

1. Replace Engine Speed (RPM) sensor.

If the specification is attained

1. Check wiring between sensor connector and engine control module as follows

1. Connect VAG1598/31 test box to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .
2. Test continuity of screening (shielded wire) between contact 1 on engine speed sensor connector and socket 108 on test box. Specification: max. 1 ohm.
3. Test continuity of negative wire from contact 2 on sensor connector to socket 90 on test box. Specification: max. 1 ohm.
4. Test continuity of signal wire from contact 3 on sensor connector to socket 82 on test box. Specification: max. 1 ohm.

If the values are not as specified

1. Correct short or open circuit in wiring between sensor connector and control module connector. ENGINE SPEED SENSOR CIRCUIT TEST: OPENS/SHORTS Terminal on sensor connector Terminal on control module connector 1 108 2 90 3 82
2. If no open circuits or short circuits are identified, replace Engine Control Module (ECM). See «MOTRONIC ENGINE CONTROL MODULE (ECM) -J220- (WITHOUT METAL ANTI -THEFT HOUSING), REPLACING»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__motronic-engine-control-module-ecm-j220) .

Engine Coolant Temperature (ECT) sensor - G62-, checking

Note. Component location of coolant temperature sensor, see COMPONENT LOCATIONS, OVERVIEW .

1. Engine cold

1. Connect vehicle diagnostic, testing and information system VAS 5051 or VAG1551 scan tool to vehicle and select engine electronics control module by entering address word "01". See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051 OR VAG1551 SCAN TOOL, CONNECTING AND SELECTING FUNCTIONS»(/audi/a6/c5-2001-2004/remont/testing-diagnostics/#on-board-diagnostic-obd-27l-v6-biturbo-apb-bel) . Engine must be at idle.

Indicated on display

Scheme 11

1. Press buttons -0- and -8- to select function "Read Measuring Value Block" and confirm entry with -Q- button.

Indicated on display

Scheme 12

1. Press buttons -0-, -0- and -4- to select "display group 004" and confirm entry with -Q- button.

Indicated on display

Scheme 13

1. Check specification in display field 3. DISPLAY GROUP 004: COOLANT TEMPERATURE WITH ENGINE IDLE Display fields 1 2 3 4 Display Group 004: Coolant temperature with engine idle Display xxxx RPM xx.xxx V xxx.x °C xxx.x °C Indicates Engine speed RPM Battery voltage Coolant temperature Intake air temperature Specified value XXXX RPM 12.0...15.0 V Temperature must increase evenly Ambient temperature up to 120 °C

If display field 3 does not display a realistic value

1. Disconnect harness connector from coolant temperature sensor.

Coolant temperature sensor with square connector

1. Connect multi-meter (resistance measurement) between terminals 1 and 3 of sensor.

Coolant temperature sensor with oval connector

1. Connect multi-meter (resistance measurement) between terminals 3 and 4 of sensor.

All

Scale A shows resistance values for temperature range 0-50 °C and scale B the values for temperature range 50-100 °C.

Scheme 14

Examples

1. 30 °C corresponds to a resistance from 1500 to 2000 ohm
2. 80 °C corresponds to a resistance from 275 to 375 ohm

If value does not match the specification

1. Replace coolant temperature sensor.

If the value does match the specification

1. Connect test box VAG1598/31 to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .

Scheme 15

1. Check following wiring connections for open circuits and short circuits to B+ or Ground (GND) COOLANT TEMPERATURE SENSOR CIRCUIT TEST (SQUARE CONNECTOR) Harness connector Terminal VAG1598/31 test box Socket 1 (Signal) 93 3 108

Scheme 16

1. Check following wiring connections for open circuits and short circuits to B+ or Ground (GND). COOLANT TEMPERATURE SENSOR CIRCUIT TEST (OVAL CONNECTOR) Harness connector Terminal VAG1598/31 test box Socket 3 108 4 (Signal) 93

1. Check wires for short circuits to each other.
2. If necessary eliminate open circuit or short circuit.

If no malfunction is identified in the wiring

1. Replace Engine Control Module (ECM). See «MOTRONIC ENGINE CONTROL MODULE (ECM) -J220- (WITHOUT METAL ANTI -THEFT HOUSING), REPLACING»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__motronic-engine-control-module-ecm-j220) .

Control module voltage supply, checking

Procedure is valid for engines with Engine code. Procedure for Engine code BEL, see CONTROL MODULE VOLTAGE SUPPLY, CHECKING, ENGINE CODE BEL .

Test requirements

1. Fuse for Engine Control Module (ECM) OK See appropriate System Wiring Diagrams article.
2. Battery voltage at least 11 V
3. Generator OK

1. Connect test box VAG1598/31 to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .
2. Switch ignition on.

Note. The B+ voltage supply for the engine control module comes via terminal 3 (terminal 15) and terminal 62 (terminal 30). The Ground (GND) connection for the engine control module is via terminals 1 and 2.

1. Connect multimeter VAG1526 (voltage measurement range) to following contacts on test box: CONTROL MODULE CIRCUIT TEST: VOLTAGE SUPPLY (ENGINE CODE APB) Contact Specification 3 + 2 approx. battery voltage 3 + 1 approx. battery voltage 62 + 2 approx. battery voltage

If the specifications are not obtained

1. Check wiring. See appropriate System Wiring Diagrams article.

1. Engine control module fuse OK See appropriate System Wiring Diagrams article.
2. Battery voltage 11 V minimum
3. Generator OK

1. Connect V.A.G 1598/31 test box to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .
2. Switch ignition on. NOTE: The B+ voltage supply for the engine control module travels via connector terminal 3 (from Motronic ECM power supply relay -J271-), connector terminal 21 (terminal 15) and connector terminal 62 (terminal 30). Ground (GND) supply of the engine control module is via connector terminals 1 and 2.
3. Connect multimeter for voltage measurement to following contacts on test box: CONTROL MODULE CIRCUIT TEST: VOLTAGE SUPPLY (ENGINE CODE BEL) Contact Specification 3 + 2 approx. battery voltage 3 + 1 approx. battery voltage 21 + 1 approx. battery voltage 62 + 2 approx. battery voltage

If the specifications are not obtained

1. Check wiring connections. See appropriate System Wiring Diagrams article.

If the specifications on terminal 3 are not obtained

1. Check Motronic ECM power supply relay, see «MOTRONIC ECM POWER SUPPLY RELAY -J271 -, CHECKING»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel__motronic-ecm-power-supply-relay-j271) .

Knock sensor control limit, checking

If the malfunction message "Knock control regulation reached" is recorded in the DTC memory the following tests must be carried out. See also measuring value blocks 20, 21, 22, 23 and 24. See MEASURING VALUE BLOCKS FOR IGNITION TIMING ANGLE RETARD .

KNOCK SENSOR CONTROL LIMIT INSPECTION

Scheme 17

Note. The displayed digit values in display fields 1 to 4 reflects the actual "ignition timing retard" via knock control from the individual cylinders. The ignition timing retard occurs via ° KW (crankshaft angle).

Scheme 18

Note. The displayed digit values in display fields 1 and 2 reflects the actual "ignition timing retard" via knock control from the individual cylinders. The ignition timing retard occurs via ° KW (crankshaft angle).

Scheme 19

Note. The displayed digit values in display fields 3 and 4 reflects the actual "ignition timing retard" via knock control from cylinders 1 and 2. The ignition timing retard occurs via °KW (crankshaft angle).

Scheme 20

Note. The displayed digit values in display fields 3 and 4 reflects the actual "ignition timing retard" via knock control from cylinders 3 and 4. The ignition timing retard occurs via °KW (crankshaft angle).

Scheme 21

Note. The displayed digit values in display fields 3 and 4 reflects the actual "ignition timing retard" via knock control from cylinders 5 and 6. The ignition timing retard occurs via °KW (crankshaft angle).

Evaluation display groups 20/21/22/23/24 - Ignition timing angle retard

EVALUATION DISPLAY GROUPS 20/21/22/23/24 - IGNITION TIMING ANGLE RETARD

Knock Sensor (KS) 1 -G61- and Knock Sensor (KS) 2 -G66-, checking

Note. It is not possible to perform an electrical test of the knock sensors themselves. Use only gold -plated terminals when repairing the terminals in the plug connectors for the knock sensors. To ensure that the knock sensors function properly it is important to keep exactly to the specified tightening torque of 20 Nm (15 ft lb) Check for corrosion in connection between knock sensor and wiring harness.

Checking knock sensors

1. Disconnect harness connector for relevant knock sensor in engine compartment.

Note. Component location overview, see COMPONENT LOCATIONS, OVERVIEW . In order to reach the connector for the knock sensor for cylinder bank 2, first remove the bolts securing the coolant reservoir and move the coolant reservoir to one side. Coolant hoses remain attached.

Assignment of connectors for engines with engine code BEL, see CONNECTORS FOR ENGINE CODE BEL .

1. Check for short circuits between all three terminals in knock sensor connector (terminals 1 + 2, 1 + 3 and 2 + 3). Specification: There must be no contact between the wires (infinite ohm).

If there is a connection between the terminals.

1. Replace knock sensor.

Note. In order to reach the knock sensors, first remove the air duct. See FUEL INJECTION VOLUME, FUEL INJECTOR LEAKAGE AND SPRAY PATTERN OF INJECTORS, CHECKING . Use special tool 3247 to remove the knock sensors.

If there is no short circuit

1. Check wiring for knock sensors.

Scheme 22

1. Connect VAG1598/31 test box to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .

Connectors for Engine code BEL

Assignment of connector wiring in vehicles with engine code BEL

Scheme 23

Assignment of 4-pin connectors on knock sensors in vehicles with engine code BEL

Scheme 24

Checking wiring between knock sensors and engine control module (cont.)

Assignment of connectors for engines with engine code BEL, see CONNECTORS FOR ENGINE CODE BEL

Scheme 25

Scheme 26

1. Check wiring connection from relevant sensor connector to...
2. ....Engine Control Module (ECM) for open circuit and/or short to B+ or Ground (GND). KNOCK SENSOR 3-PIN CONNECTORS AND VAG1598/31 TEST BOX, SOCKET Knock Sensor (KS) 1 -G61- (Bank 1) 3-pin connector on wiring harness, socket VAG1598/31 test box, socket 1 (Ground) 99 2 (signal) 106 3 (shielded) 108 Knock sensor (KS) 2 -G66- (Bank 2) 3-pin connector on wiring harness, socket VAG1598/31 test box, socket 1 (Ground) 99 2 (signal) 107 3 (shielded) 108 Resistance in wiring: max. 1.5 ohm
3. Repair any open/short circuit as necessary.

Camshaft Position (CMP) sensor 2 -G163- and Camshaft Position (CMP) sensor 1 -G40-, checking

Note. Component locations of CMP sensors, see FUEL INJECTION VOLUME, FUEL INJECTOR LEAKAGE AND SPRAY PATTERN OF INJECTORS, CHECKING . The Camshaft Position (CMP) sensor 2 -G163- is located at the rear of the left -hand cylinder head (Bank 2). The Camshaft Position (CMP) sensor 1 -G40- is located at the front of the right-hand cylinder head (Bank 1).

Checking activation of CMP sensor

Use test leads VAG1594 connector test kit when performing the following tests.

Scheme 27

1. Push back rubber grommet on relevant CMP sensor connector.
2. Connect VAG1527 LED voltage tester to terminals 1 and 2 of CMP sensor connector from behind (without disconnecting connector from sensor). NOTE: The connector terminals are numbered on the back of the connector.
3. Operate starter for few seconds. LED voltage tester should blink briefly once every two engine revolutions.

Note. LED voltage testers with a low current draw continue to glow faintly between impulses from the engine control module (rather than going out completely) and become much brighter when receiving an impulse.

If the LED voltage tester does not blink

1. Check voltage supply.

Checking voltage supply for CMP sensor

1. Disconnect harness connector from relevant CMP sensor.
2. Switch ignition on.
3. Connect multimeter (Fluke 83 or equivalent) (voltage measurement range) between engine Ground (GND) and socket 1 of connector. Specification: approx. 5 V

Checking signal wire for CMP sensor

1. Connect multimeter (Fluke 83 or equivalent) (voltage measurement range) between engine Ground (GND) and socket 2 of relevant connector. Specification: approx. battery voltage

Scheme 28

1. Connect VAG1598/31 test box to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .
2. Connect multimeter (Fluke 83 or equivalent) (resistance measurement range) between socket 3 on relevant connector and contact 108 of test box. Specification: Continuity Resistance in wiring: max. 1.5 Ohms

If all specifications are reached but the LED voltage tester does not blink (measurement taken between terminals 1 and 2 without unplugging connector and while operating starter)

1. Replace relevant CMP sensor.

If specifications are obtained

1. Go to «CHECKING WIRING BETWEEN CMP SENSOR AND ENGINE CONTROL MODULE (ECM)»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel__checking-wiring-between-cmp-sensor-and) .

Checking wiring between CMP sensor and Engine Control Module (ECM)

1. Connect VAG1598/31 test box to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(/audi/a6/c5-2001-2004/remont/fuel-system/#multiport-fuel-injection-mfi-27l-v6-biturbo-apb-bel__wiring-and-component-check-with-vag159831) .
2. Check wiring connection from CMP sensor to engine control module for open circuit and/or short circuit to B+ or Ground (GND). CMP SENSOR 3-PIN CONNECTORS AND VAG1598/31 TEST BOX, SOCKET Camshaft Position (CMP) sensor 2 -G163- (Bank 2) 3-pin connector on wiring harness, socket VAG1598/31 test box, socket 1 (B+) 98 2 (signal) 86 3 (Ground (GND)) 108 Camshaft Position (CMP) sensor 1 -G40- (Bank 1) 3-pin connector on wiring harness, socket VAG1598/31 test box, socket 1 (positive) 98 2 (signal) 87 3 (Ground (GND)) 108 Resistance in wiring: max. 1.5 ohm
3. Repair any open/short circuit as necessary.

If all the test results so far have been OK but a malfunction related to the camshaft position sensor (Hall sensor) is displayed again after erasing the DTC memory as a test measure, the following might be the cause

1. Rotor ring (trigger wheel) for camshaft position sensor (Hall sensor) misaligned; test phase position.

Checking phase position of CMP sensor

1. Connect vehicle diagnostic, testing and information system VAS5051 or VAG1551 scan tool and select engine electronics control module by entering address word "01". See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051 OR VAG1551 SCAN TOOL, CONNECTING AND SELECTING FUNCTIONS»(/audi/a6/c5-2001-2004/remont/testing-diagnostics/#on-board-diagnostic-obd-27l-v6-biturbo-apb-bel) . Engine must be idling.

Indicated on display

Scheme 29

1. Press buttons -0- and -8- to select function "Read Measuring Value Block" and confirm entry with -Q- button.

Indicated on display

Scheme 30

1. Press buttons -0-, -9- and -3- to select "display group 093" and confirm entry with -Q- button.

Indicated on display

Scheme 31

1. Check specified display values for CMP sensors. DISPLAY GROUP 093: PHASE POSITIONS OF HALL SENSORS (BANK 1 AND BANK 2) WITH ENGINE IDLING Display fields 1 2 3 4 Display Group 093: Phase positions of Hall sensors (Bank 1 and Bank 2) with engine idling Display xxx RPM xx % 0 +/- 6 °KW 0 +/- 6 ° KW Indicates Engine speed (RPM) Engine load Phase position Bank 1 Phase position Bank 2 Work range min.: 750 RPM max.: 6800 RPM min.: 15 % max.: 175 % -20.3 to 14.8 ° KW -20.3 to 14.8 ° KW Specified value 650 - 850 RPM 15...25% 0 +/- 6 °KW 0 +/- 6 ° KW Note If readouts do not match specifications, unbolt CMP sensor and check whether rotor ring is properly mounted on camshaft. If it is incorrectly mounted, the locating lug will be flattened when the securing bolt is tightened. Also check valve timing. See «TOOTHED BELT, REMOVING AND INSTALLING»(/audi/a6/c5-2001-2004/remont/mechanical/#27l-v6-5v-bi-turbo-engine-codes-apb-bel) .

Test sequence

1. Connect vehicle diagnostic, testing and information system VAS5051 or VAG1551 scan tool and select engine electronics control module by entering address word "01". See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051 OR VAG1551 SCAN TOOL, CONNECTING AND SELECTING FUNCTIONS»(/audi/a6/c5-2001-2004/remont/testing-diagnostics/#on-board-diagnostic-obd-27l-v6-biturbo-apb-bel) . Engine must be at idle.

Indicated on display

Scheme 32

1. Press buttons -0- and -8- to select function "Read Measuring Value Block" and confirm entry with -Q- button.

Indicated on display

Scheme 33

1. Press buttons -0-, -1- and -4- to select "display group 014" and confirm entry with -Q- button.

Indicated on display

Scheme 34

1. Check misfire recognition. DISPLAY GROUP 014: MISFIRE RECOGNITION Display fields 1 2 3 4 Display Group 014: Misfire recognition Display xxx / RPM xx.x % xxx --- Indicated Engine speed (RPM) Load Total misfires Misfire recognition Work range min.: 650 RPM max.: 6800 RPM min.: 0 max.: 175 activated locked Specified value 650 - 720 RPM 15.0 - 25.0 % 0...15 activated Note --- --- If specified value is not reached: see «EVALUATION DISPLAY FIELD 3»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel) . See also «DISPLAY GROUP 015: MISFIRE RECOGNITION FROM CYLINDER 1, 2 AND 3»(/audi/a6/c5-2001-2004/remont/ignition-system/#ignitionglow-plug-system-27l-v6-biturbo-apb-bel)

If specified value is reached

1. Press --> button.

Indicated on display (select function)

Scheme 35

Evaluation display group 014, display field 3

EVALUATION DISPLAY GROUP 014, DISPLAY FIELD 3

The following measuring value blocks display misfiring of individual cylinders

DISPLAY GROUP 015: MISFIRE RECOGNITION FROM CYLINDER 1, 2 AND 3

DISPLAY GROUP 016: MISFIRE RECOGNITION FROM CYLINDER 4, 5 AND 6

Evaluation display groups 015 and 016

EVALUATION DISPLAY GROUPS 015 AND 016

See also:
• COMPONENT LOCATIONS, OVERVIEW
• WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX
• VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051 OR VAG1551 SCAN TOOL, CONNECTING AND SELECTING FUNCTIONS
• INTAKE MANIFOLD, REMOVING AND INSTALLING
• MOTRONIC ENGINE CONTROL MODULE (ECM) -J220- (WITHOUT METAL ANTI -THEFT HOUSING), REPLACING
• COMPRESSION, CHECKING
• FUEL INJECTION VOLUME, FUEL INJECTOR LEAKAGE AND SPRAY PATTERN OF INJECTORS, CHECKING
• FUEL INJECTORS, CHECKING
• IGNITION COILS, CHECKING, ENGINE CODE BEL
• MISFIRE RECOGNITION, CHECKING
• CHECKING VOLTAGE SUPPLY OF THE IGNITION COILS
• MOTRONIC ECM POWER SUPPLY RELAY -J271 -, CHECKING
• POWER OUTPUT STAGES FOR IGNITION COILS, CHECKING
• CHECKING VOLTAGE SUPPLY TO POWER SUPPLY RELAY
• CHECKING WIRING CONNECTION BETWEEN POWER SUPPLY RELAY AND ENGINE CONTROL MODULE
• KNOCK SENSOR (KS) 1 -G61- AND KNOCK SENSOR (KS) 2 -G66-, CHECKING
• CONNECTORS FOR ENGINE CODE BEL
• CHECKING WIRING BETWEEN CMP SENSOR AND ENGINE CONTROL MODULE (ECM)
• IGNITION COILS, CHECKING