Ignition Timing: Testing and Inspection
Camshaft adjustment system, checking
Required special tools and test equipment
- VAG 1551 Scan Tool (ST) with VAG 1551/3 adapter cable
- Multimeter US 1119 (Fluke 83 or equivalent)
- VW 1594 connector test kit
Function
The camshaft adjustment is dependent on engine speed and load. The electrical solenoid valves for camshaft adjustment (-N205- and -N208-) are switched to apply oil pressure to the mechanical camshaft adjusters, which adjusts the camshaft timing.
Camshaft adjustment function, checking
- Connect VAG 1551/1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (engine running at idle).Refer to "Scan tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1551/VAG 1552 Scan Tool" Testing and Inspection
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08, and press -Q- button to confirm input.
Indicated on display
Read Measuring Value block HELP
Input display group number XXX
- Press buttons -0-, -9- and -0- to input display group number 90 (090), and press -Q- button to confirm input.
Indicated on display (1-4 = display groups)
Read Measuring Value Block 90 ->
1 2 3 4
NOTE:
Display field 2 indicates whether the engine control module has activated the camshaft adjustment.
- "CS-ctrl OFF:" camshaft adjustment is not active.
- "CS-ctrl ON:" camshaft adjustment is active (this can only be attained during a test drive)
Display fields 3 and 4 show whether the camshaft adjustment did actually occur (via input from sensors):
- Normal Position: -3.0 ° to 6.0 ° KW.
- Shifted position: 16.0 ° KW to 25.0 ° KW.
NOTE: If, during the test drive, display field 3 and/or 4 displays a value between 6.0 ° KW and 16.0 ° KW, the electrical valves for camshaft adjustment have switched the oil pressure to the respective mechanical camshaft adjuster, but it cannot attain the correct end position (e.g. due to sluggishness).
WARNING!
A second technician is required to operate the VAG 1551 scan tool during the road test. Safety precautions.
- Accelerate from rest in 1st gear (manual) or with selector lever in "2" position (automatic).
- Check specified values for camshaft adjustment (display fields 2-4)
If specified values are attained:
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06, and press -Q- button to confirm input.
Valves for camshaft adjustment, checking
- Connect VAG 1551/1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (with engine running at idle).Refer to "Scan tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1551/VAG 1552 Scan Tool" Testing and Inspection
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -3- to select "Output Diagnostic Test Mode" function 03.
Indicated on display
Rapid data transfer Q
03 - Output Diagnostic Test Mode
- Press -Q- button to confirm input.
Indicated on display
Output Diagnostic Test Mode ->
Camshaft adjustment 1
- Check using output DTM and activate camshaft adjustment. Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03)" Testing and Inspection
Valves 1 and 2 for camshaft adjustment, - N205- and -N208-, must click audibly.
If the valves do not click:
- Check as described in test procedures that follow.
Checking solenoid valves for camshaft adjustment electrically
- Disconnect harness connector from valve.
- Using multimeter with auxiliary wires from VAG 1594, measure resistance across terminals on valve.
Specified value: 10-18 ohms
If resistance is not as specified:
- Replace solenoid valve.
Checking voltage supply of valves for camshaft adjustment
- Disconnect harness connector from valve.
- Connect LED tester VAG 1527 between engine ground and terminal 1 of connector (B+).
- Crank starter for several seconds (engine can start).
LED in voltage tester must light up.
If LED does not light up, conduct the following tests:
- Check fuse for valves for camshaft adjustment.
- Check wiring from terminal 1 on 2-pin connector to fuse for continuity per wiring diagram.
- Check fuel pump relay and signal to relay. Testing and Inspection
Checking signal to valves for camshaft adjustment
- Disconnect harness connector from valve.
- Connect LED tester VAG 1527 between connector terminals 1 and 2.
- Check using output DTM and activate camshaft adjustment. Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03)" Testing and Inspection
LED must flash.
If LED does not flash or stays on continuously:
- Connect VAG 1598/22 test box to Motronic ECM harness connector and proceed as follows:Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1598/22 Test Box" Testing and Inspection
If LED does not flash:
- Check wiring from terminal 2 of connector for valve to terminal 55 of ECM/test box for continuity and short circuit to B+.
If LED stays lit constantly:
- Check wiring between valve connector terminal 2 and ECM/test box terminal 55 for short circuit to Ground.
Specified value: max. 1 Ohms.
If the wiring is OK:
- Replace Motronic ECM -J220-.
- Carry out adaptation of throttle valve control module to ECM.
- Check readiness code. If Diagnostic Trouble Code (DTC) memory has been erased, or ECM was disconnected, generate new readiness code.
Refer to "Moniters, Trips and/or Drive Cycle (Readiness Codes)/Checking Readiness Code" Testing and Inspection
Refer to "Moniters, Trips and/or Drive Cycle (Readiness Codes)/Generating Readiness Code Testing and Inspection
If no malfunction has been found in any of the previous tests:
- Replace respective mechanical camshaft adjuster.