Golf III L4-1984cc 2.0L SOHC (1993)
^
LED must light up.
If NO:
-
Repair short/open circuit using wiring diagram.
Heated Oxygen sensor (HO2S) and Oxygen sensor control, checking.
-
Test using VAG 1551 with engine idling.
-
Perform Engine basic setting using repair procedures in Repair Group 01.
-
Ensure that exhaust system is not leaking between three way Catalytic Converter and cylinder head.
-
Ensure that voltage supply for Heated Oxygen sensor heater circuit is OK (see Perform Output Diagnostic Test Mode Function 03 step 9) (Engine
not running).
-
Go to "Read Measuring Value Block" Function (08) display group 01.
-
Indicated on display (14=display field).
Read measuring value block 1
1 2 3 4
Continue testing only when:
^
Engine Coolant Temperature is over 80°C (176°F - channel 2).
^
Engine has run 2 minutes at idle.
-
Read Oxygen Sensor factor in channel 3.
^
Value displayed must fluctuate up and down. If value in channel 3 does not fluctuate:
-
Ensure that H02S heater is functioning properly.
-
Briefly raise engine speed above 2000 rpm and repeat test.
-
Press buttons -0-and-6- to select Function 06 "End Output".
-
Press -Q- to confirm input.
If Oxygen sensor display does not change even during acceleration:
-
Disconnect Heated Oxygen sensor harness connector.
-
Connector adapter lead from VW1594 to cavity 4 (wiring to Motronic Engine Control Module J220) and hold to Ground (GND).
^
Value in channel 3 must increase. If YES:
-
Replace Heated Oxygen Sensor.
If NO:
-
Perform VAG 1598 Electrical test of wiring to H02S see Repair Group 01.
-
Contact VW Technician Helpline if it is necessary to replace Motronic Engine Control Module (ECM) (J220).
