Ignition System: Testing and Inspection
Ignition System, Checking
For all Ignition/Glow plug system component locations.
For all Ignition/Glow plug system removal/installation procedures and torque specifications.
Check the Technical Bulletins for information that may supersede any information included in this information.
• All manufacturers special tools as well as common tools may contain a manufacturer specific part number. These tools may be substituted with an equivalent aftermarket tool or are available for purchase through VW.
• Manufacturers special tools as well as common tools that contain a manufacturer specific part number may be referenced in the test procedure illustrations showing the tool use or installation. If the manufacturer specific tool is not being used, an equivalent aftermarket tool may be installed in the same manner as the manufacturers special tool.
• The manufacturers test box Adapter - 68 Pin (VAG1598/18)Adapter - 68 Pin (VAG1598/18) is available for purchase or rental..
The following table provides quick links to all chapters in this section.
Safety Precautions
CAUTION!
Observe the following for all installations, especially in the engine compartment due to lack of room:
• Route lines of all types (e.g. for fuel, hydraulic, EVAP canister system, coolant and refrigerant, brake fluid, vacuum) and electrical wiring so that the original path is followed.
• Watch for sufficient clearance to all moving or hot components.
• Fuel system is under pressure! Before opening system, place rags around the connection point. Then release pressure by carefully loosening connection.
• Test equipment must always be secured to the rear seat and operated by a second person.
• Test and measuring equipment that is operated from the passenger seat, the person seated could be injured in the event of an accident involving deployment of the passenger-side airbag.
• Do not touch or disconnect ignition wires when engine is running or turning at starting RPM.
• Only disconnect and reconnect wires for injection and ignition system, including test leads, if the ignition is turned off.
CAUTION!
The use of nails, paper clips, or another unauthorized materials to back-probe electrical harness connectors is strictly prohibited and may cause damage to the electrical harness connectors, terminal ends or damage to a component. Use only the manufacturers test lead kit or an equivalent aftermarket test lead kit for back-probing all electrical harness connectors.
Glow Plug System, Technical Data
Glow Plugs, Checking
Special tools, testers and auxiliary items required
• Multimeter.
• Diode test lamp.
• Wiring diagram.
Test requirements
• Fuse (S39) OK.
• The Glow Plug Relay (J52) OK.
• Battery voltage at least 12.5 volts.
• Ground (GND) connections between engine/transmission/chassis OK.
• Ignition switched off.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ General Diagnosis ] General Diagnosis.
Start diagnosis
- Disconnect the Engine Coolant Temperature (ECT) Sensor (G62) electrical harness connector - 1 -.
• A "cold engine" condition is simulated when the ECT electrical harness connector is disconnected and the ignition is switched on for the appropriate glow period.
Checking voltage supply
- Disconnect the Glow Plug electrical connectors.
- Using a Multimeter, check each Glow Plug electrical connector, in sequence, from 1 to 4, to Ground (GND) for voltage.
Specified value: Battery voltage for 20 seconds.
If the specified value is not obtained:
- Check the wiring from the Glow Plug electrical harness to the Automatic Glow Time Control Module (J179) pins for an open circuit, short circuit to each other or to Battery (+) or Ground (GND).
Specified value: 1.5 ohms.
If the specified value was not obtained:
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring and the voltage supply was OK:
Checking Glow Plug
- Using a Diode test lamp, check the Glow Plug from Battery (+) to each individual Glow Plug.
The Diode test lamp must light up.
If the Diode test lamp does not light up:
- Replace the faulty Glow Plug.
- Perform a road test to verify repair.
If the fault does not return:
Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Readiness Code.
- End diagnosis.
If the fault does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Recheck the voltage supply.
- Assembly is performed in the reverse of the removal.
Final procedures
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Readiness Code.
Automatic Glow Time Control Module, Checking
Special tools, testers and auxiliary items required
• Multimeter.
• wiring diagrams.
Test requirements
• The fuse for the engine electronics OK.
• The Ground (GND) connections at the engine and transmission OK.
• The battery voltage at least 12.5 V.
• The generator OK.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ General Diagnosis ] General Diagnosis
Start diagnosis
- Using a Multimeter, check the following wiring connection for voltage.
- Turn key on
Specified value: 12.5 V
If the specified value was not obtained:
- Using a Multimeter, check the Automatic Glow Time Control Module (J179) socket 6/30 to Fuse 51 on fuse panel.
- Check the electrical harness connectors for damage, corrosion, loose or broken terminals.
- If necessary, repair the wiring connection.
If no malfunctions are found in the wiring:
Checking Ground (GND)
- Using a Multimeter, check the Automatic Glow Time Control Module (J179) socket 9/31 to the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248) electrical harness connector terminal T94/4 for an open circuit.
Specified value: 1.5 ohms.
If the specified value was not obtained:
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the wiring connection.
If no malfunctions are found in the wiring and the voltage supply was OK:
- Replace the Automatic Glow Time Control Module (J179).
- Perform a road test to verify repair.
If the fault does not return:
Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Readiness Code.
If the fault does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248). Refer to => [ Diesel Direct Fuel Injection ECM, Replacing ] Diesel Direct Fuel Injection ECM, Checking.
- Assembly is performed in the reverse of the removal.
Final procedures
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Readiness Code.