Function tests Oxygen sensor and oxygen sensor control before catalytic converter, checking

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Junior Cummings
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1 Seite 1 von 5 Function tests Oxygen sensor and oxygen sensor control before catalytic converter, checking Special tools and equipment VAG1551 scan tool (or VAG1552 mobile scan tool) with VAG1551/3B cable VAG1598/31 adapter cable VAG1526 or Fluke 83 multimeter VAG1594 connector test kit Electrical Wiring Diagram Test requirements Engine coolant temperature must be at least 80 C, => display group 04, display field 3 Exhaust system must be properly sealed between catalytic converter and cylinder head. Function test Connect VAG1551 scan tool (or VAG1552). Start engine and select Engine Control Module (ECM) using address word 01. (connecting scan tool and selecting ECM => Page 01-20) Indicated on display: Rapid data transfer HELP Press buttons -0- and -8- to select "Read measuring value block" function 08. Press -Qbutton to confirm input. Select function XX Indicated on display: Read measuring value block HELP Press buttons -0-, -3- and -0- to select "Display group number 30". Press -Q- button to confirm input. Enter display group number XXX Check status of oxygen sensor control before catalytic converter (display field 1): Specification: x 1 1 Read measuring value block 30 Note: The sensor heater is pulsed by the Engine Control Module (ECM). This is why the indication for the sensor heater alternates between 0 and 1. Explanation of 3-digit value in display field 1: When display positions = Oxygen sensor control active 1 Oxygen sensor operationally ready 1 Oxygen sensor heating on If oxygen sensor heater is not active: Test oxygen sensor heater before catalytic

2 Seite 2 von 5 converter => Page If oxygen sensor or oxygen sensor control is not active: Test oxygen sensor wires => Page Additionally, for engine code ATW: Check oxygen sensor voltage => Page Change to display group 32 as follows: Press -C- button. Press buttons -0-, -3- and -2- to select "Display group number 32". Press -Q- button to confirm input. Check oxygen sensor adaptation values (additive) at idle in display field 1. Read measuring value block 32 Specification: to 10.0% Check oxygen sensor adaptation values (multiplicative) at partial throttle in display field 2. Specification: to 10.0% => Page , Evaluation display group 32 Change to display group 33 as follows: VAG1551 Scan Tool (ST): Press buttons -3- and -3- VAG1552 mobile scan tool: Press button. Observe oxygen sensor control in display field 1. Read measuring value block 33 Indication should oscillate in the range from to 10.0% by at least 2%. Press buttons -0- and -6- to select "End data transfer" function 06. Press -Q- button to confirm input. Observe safety precautions that apply to road tests => Page Clean Heated Oxygen Sensor (HO2S) with a

3 Seite 3 von 5 road test and repeat test. If specified value in display field 1 is not obtained even after road test or if value does not fluctuate at least 2%: Checking oxygen sensor voltage Only engine code ATW Check oxygen sensor voltage in display field 2. Voltage must oscillate at least 20 times per minute in range from 0 to 1.0 volts. If indication in display field 2 remains constant on one value: Continue testing according to following table. Indicated Cause Continue testing => Page 24-89, checking primary voltage Between and volts V V Open circuit Short circuit to B+ Short circuit to Ground (GND) Checking primary voltage Only engine code ATW => Page 24-90, checking oxygen sensor wiring Disconnect 4-pin harness connector (black) to Heated Oxygen Sensor (HO2S) -G39- (item no. 1). Use adapter cables from VAG1594 to connect multimeter to terminals (ECM connector) for voltage measurement. Switch on ignition and measure primary voltage.

4 Seite 4 von 5 Specification: 0.40 to 0.50 volts Switch ignition off. Test oxygen sensor wires => Page Checking oxygen sensor wires Connect VAG1598/31 adapter cable to control module wiring harness. Engine Control Module (ECM) is not connected. Engine code ATW Check wires between test box and 4-pin connector (to control module) for open circuit according to wiring diagram. 1. Terminal 3 + socket Terminal 4 + socket 70 Wire resistance: max: 1.5 Ω Check wires at connector terminal 3+4 for short circuit to terminal 1+2 according to diagram. If no malfunctions are found in wires: Engine codes AUG, AWM Disconnect 6-pin harness connector (black) to Heated Oxygen Sensor (HO2S) -G39- (item no. 1).

Seite 5 von 5 Check wires between test box and 6-pin connector (to control module) for open circuit according to wiring diagram. 1. Terminal 1 + socket 70 2. Terminal 2 + socket 71 3.

5 Seite 5 von 5 Check wires between test box and 6-pin connector (to control module) for open circuit according to wiring diagram. 1. Terminal 1 + socket Terminal 2 + socket Terminal 4 + socket Terminal 5 + socket Terminal 6 + socket 52 Wire resistance: max: 1.5 Ω Also check all wires for short circuit to each other. Specification: Ω If no malfunctions are found in wires:

Oxygen sensor control,

Page 1 of 37 24-71 Oxygen sensor control, checking Oxygen sensor and oxygen sensor control before catalytic converter, checking Special tools and equipment - or VAG1526A VAG1594A VAG1598/31 VAS5051 with