Volkswagen New Beetle. Manual - part 1821

See FUEL INJECTOR HARNESS CONNECTOR/VAG TEST BOX SOCKET IDENTIFICATION
table. See Fig. 25 .

Resistance should be a maximum of 1.5 ohms for each reading. Check wiring in fuel injector pin harness
connector for short circuits to one another and for short circuits to ground and B+. If resistance
measurements are okay and no short circuits exist. Replace ECM. After repairs, erase DTC memory.
Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN
PROCEDURE . If any resistance measurement is not okay, or a short circuit exists, repair circuit(s) as
necessary. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM
WIRING DIAGRAMS article. After repairs, erase DTC memory. Verify repair. Test is complete.
Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .

7. Check fuel pressure and fuel pressure regulator. See FUEL SYSTEMS in appropriate SYSTEM &

COMPONENT TESTING article. If fuel pressure is okay, go to next step. If fuel pressure is not okay.
Repair as necessary. After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM
relearn procedure. See TEST DRIVE RELEARN PROCEDURE .

8. Check fuel injector volume (possible blocked or leaking injector). See FUEL SYSTEMS in appropriate

SYSTEM & COMPONENT TESTING article. If fuel injector volume is okay, and fuel injectors do not
leak more than 2 drops per minute each, go to next step. If fuel injector volume is not okay and /or any
fuel injectors leak more than 2 drops per minute each, repair as necessary. After repairs, erase DTC
memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE
RELEARN PROCEDURE .

DTC P0300/16684 & P0301/16685: MISFIRE RECOGNITION

Code Definition

DTC P0300/16684
Random/Multiple Cylinder Misfire Recognized

DTC P0301/16685
Misfire Cylinder No. 1

Test Requirements

Ensure vehicle has a sufficient amount of fuel. Ensure Camshaft Position (CMP) sensor (G163) is okay. See
DTC P1337/17745, DTC P1338/17746 & DTC P1340/17748 . Ensure Engine Speed (RPM) sensor (G28) is
okay. See DTC P0321/16705 . Ensure all fuses are okay, battery voltage is at least 11.5 volts and fuel pump
relay is okay. Ensure all electrical accessories are off and A/C is off. Ensure engine is mechanically sound.
Ensure no intake or exhaust system leaks exist. Ensure engine coolant temperature is at least 176°F (80°C). On
vehicles with M/T, gear shifter must be in neutral with parking brake set. On vehicles with A/T, selector lever
must be in park or neutral with parking brake set.

NOTE:

If a test ends with ECM replacement, before replacing ECM be certain that, all
wiring, power and ground supplies are okay. See ENGINE PERFORMANCE in
SYSTEM WIRING DIAGRAMS article in ELECTRICAL and ECM GROUND &
VOLTAGE SUPPLY .

2003 Volkswagen New Beetle GLS

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

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Test Procedure

1. Turn ignition off. Remove and check condition of ignition wire and spark plug at misfiring cylinder.

Ignition wire w/spark plug connector should have 4000-8000 ohms of resistance. If ignition wire is not
okay, replace ignition wire set. Check spark plug for correct heat range. If spark plug(s) are okay, go to
next step. If spark plug(s) are not okay, replace spark plugs as a set. After repairs, erase DTC memory.
Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN
PROCEDURE .

2. Using DVOM, check supply voltage between terminals No. 1 and 6. See Fig. 29 . Voltage should a

minimum of 11.5 volts, (battery voltage). If voltage is okay, go to step 4 . If voltage is not okay, go to
next step.

3. Using DVOM, check wiring for open circuit between ignition coil harness connector terminal No. 6 and

power supply relay using wiring diagram. See ENGINE PERFORMANCE in SYSTEM WIRING
DIAGRAMS article in ELECTRICAL. See Fig. 29 . Check wiring for open circuit between ignition coil
harness connector terminal No. 1 and ground. See Fig. 29 . Resistance reading should be a maximum of
1.5 ohms for each reading. If resistance readings are okay, go to next step. If any resistance reading is not
okay, repair as necessary. After repairs, erase DTC memory. Verify repair. Test is complete. Perform
ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .

4. Using scan tool, check fuel injectors. See OUTPUT DIAGNOSTIC TEST MODE . Fuel injectors

should audibly click. If all fuel injectors click, go to next step. If any fuel injector does not click, repair as
necessary. See DTC P0267/16651, DTC P0268/16652, DTC P0270/16654 & DTC P0271/16655 . After
repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST
DRIVE RELEARN PROCEDURE .

Remove fuse No. 32 (disables fuel injectors). Using LED test light, check voltage supply to ignition coil
of cylinder indicated to be misfiring. See IGNITION COIL HARNESS CONNECTOR VOLTAGE
TEST POINTS IDENTIFICATION table. Disconnect ignition coil harness connector. See Fig. 28 .
Have a second person crank engine. LED should flash. Turn ignition off. If LED did not flash (no voltage
is present), go to next step. If LED flashed (voltage readings are okay) and voltage is present between
terminals No. 1 and 6, replace faulty ignition coil w/output stage. After repairs, erase DTC memory.
Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN
PROCEDURE .

CAUTION: When checking misfires, it is essential to ensure fuel is not contaminated

and that engine is mechanically sound (e.g. compression is okay).

NOTE:

Output Diagnostic Test Mode is used when using Scan Tools VAG 1551/1552 or
VAS 5051/5052, always continue with output diagnostic test mode until last
component in output diagnostic test mode test sequence has been checked.
Follow scan tool manufacturer's instructions.

WARNING:

During following test do not touch ignition coils, ignition coil
harness connectors or test cables.

2003 Volkswagen New Beetle GLS

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

Helpmelearn Repair Manuals

Wednesday, December 14, 2005 8:49:56 AM

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IGNITION COIL HARNESS CONNECTOR VOLTAGE TEST POINTS IDENTIFICATION

6. Turn ignition off. Disconnect ECM harness connector, leave ECM disconnected from test box. Connect

Test Box (VAG 1598/31) to ECM harness connector. See CONNECTING VAG TEST BOX . Using
DVOM, check resistance between the following ignition coil/output stage harness connectors and VAG
test box sockets. See IGNITION COIL HARNESS CONNECTOR/TEST BOX SOCKET
IDENTIFICATION table and Fig. 29 . Resistance should be a maximum of 1.5 ohms for each reading.
If resistance readings are okay, go to next step. If resistance reading is not okay, repair as necessary. After
repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST
DRIVE RELEARN PROCEDURE .

IGNITION COIL HARNESS CONNECTOR/TEST BOX SOCKET IDENTIFICATION

7. Check wiring in ignition coil harness connector for short circuits to one another and for short circuits to

ground and B+. If resistance measurements are okay and no short circuits exist. Replace faulty ECM. See
ENGINE CONTROL MODULE REMOVAL & INSTALLATION . After repairs, erase DTC
memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE
RELEARN PROCEDURE .

Cylinder

Ignition Coil Harness Connector Terminals

1 & 2

1 & 3

1 & 4

1 & 5

Cylinder

Ignition Coil Harness Connector Terminal

VAG Test Box Socket

102

103

2003 Volkswagen New Beetle GLS

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

Helpmelearn Repair Manuals

Wednesday, December 14, 2005 8:49:56 AM

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Fig. 28: Locating Ignition Coil/Output Stage Harness Connector
Courtesy of VOLKSWAGEN UNITED STATES, INC.

Fig. 29: Identifying Test Points On Ignition Coil/Output Stage Harness Connector

2003 Volkswagen New Beetle GLS

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

Helpmelearn Repair Manuals

Wednesday, December 14, 2005 8:49:56 AM

Page 87

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