Volkswagen Golf / Golf GTI / Golf Variant. Manual - part 210

Step

Procedure

Result / Action to Take

4

• Final Procedure
• Perform a road test to verify repair.
• Do any DTC’s return:

– YES:

♦ Check the DTC memory. Refer to

⇒ “3.3.4 Diagnostic Mode 04 - Erase DTC

Memory”, page 26

 .

♦ Perform the diagnostic procedure for that DTC.
– NO:

♦ Repair is complete. Generate readiness code.

Refer to 

⇒ “3.2 Readiness Codes”, page 19

 .

♦ Return vehicle to Customer.

3.6.27

Oxygen Sensor 1 After Catalytic Con‐

verter - GX7- , Checking

General Description
The Oxygen Sensor 1 After Catalytic Converter - GX7- down‐

stream of the primary catalytic converter supplies the Engine

Control Module - J623- with a voltage signal (nonlinear) indicating

“rich” or “lean. If the primary catalytic converter is supersaturated

with oxygen (lean mixture), Oxygen Sensor 1 After Catalytic Con‐

verter - GX7- will send the Engine Control Module - J623- a

nonlinear signal indicating the lean mixture condition. The mixture

is then enriched with fuel until the oxygen has been “displaced”

from the catalytic converter. This condition, in turn, is registered

by Oxygen Sensor 1 After Catalytic Converter - GX7- as a non‐

linear signal indicating the rich mixture condition. The mixture is

then leaned out by the Engine Control Module - J623- . If the

nonlinear signal is received again, the mixture will again be en‐

riched. The frequency, or period, during which the mixture is

enriched or leaned out is variable, being dependent on the gas

flow rate (engine load) at that moment.
Note the Oxygen Sensor 1 After Catalytic Converter - GX7- is also

referred to as the Oxygen Sensor After Three Way Catalytic Con‐

verter - G130- .
The Oxygen Sensor 1 After Catalytic Converter - GX7- contains

the following components:
♦ Oxygen Sensor After Three Way Catalytic Converter - G130-
♦ Heater For Oxygen Sensor 1 After Catalytic Converter - Z29-
The Oxygen Sensor 1 After Catalytic Converter - GX7- compo‐

nents cannot be serviced separately, it must be serviced as a unit.
Special tools and workshop equipment required
♦ Multimeter.
♦ Wiring Diagram.
♦ Scan Tool.
Test requirements
• Fuses OK.
• Battery voltage OK.
• Switch OFF all electrical and electronic accessories.
• Vehicles with Auto. Transmission, ensure Selector Lever po‐

sition is in “P”.

• Vehicles with Man. Transmission, ensure Shifter Lever posi‐

tion is in “N” with Parking Brake applied.

GTI 2014 ➤

Generic Scan Tool - Edition 04.2015

3. Diagnosis and Testing    

513

Pro

te

c

t

ed

  b

y

  co

p

y

rig

h

t. 

C

o

p

y

in

g

  fo

r 

pr

iv

a

t

e

 o

r

 c

o

m

m

e

r

c

ia

l 

p

u

rp

o

s

e

s

,

 i

n

 p

a

rt

o

r i

n

 w

h

o

le

, 

is

 n

o

t

 p

e

r

m

it

t

e

d

 u

n

l

e

s

s

 a

ut

ho

r

i

s

ed

 b

y

 V

olk

sw

a

ge

n AG

.

 

V

olk

s

w

a

g

en

 AG do

es 

n

ot g

uar

ante

e

 or a

c

c

ep

t

 a

ny

 

li

a

b

i

li

t

y

 w

ith

 r

e

s

p

e

c

t

 t

o

 

th

e

 c

o

rr

e

c

t

n

e

s

s

 

o

f

in

fo

r

m

a

tio

n

 in

 th

is

 d

o

c

um

en

t.

C

o

py

rig

ht b

y

 

V

olk

sw

a

ge

n

 

A

G.

• Coolant Temperature: ≥ 80° C.
• Observe all safety precautions:

⇒ “1.1 Safety Precautions”, page 2

 .

• View clean working conditions:

⇒ “1.2 Clean Working Conditions”, page 3

 .

• For Hybrid vehicles refer to:

⇒ “1.3 High Voltage System General Warnings”, page 4

 .

Test Procedure

Step

Procedure

Result / Action to Take

1

• PERFORM: Preliminary Check to verify the

customers concern. Refer to

⇒ “3.1 Preliminary Check ”, page 18

 .

– Was Complaint verified?

– YES:

♦ GO TO: Step 2 

⇒ page 514

 .

– NO:

♦ GATHER more information from customer

about the complaint.

2

• IGNITION: OFF.
• DISCONNECT: Oxygen Sensor 1 After Cata‐

lytic Converter - GX7- harness connector.

• CHECK: Oxygen Sensor 1 After Catalytic Con‐

verter - GX7- component connector terminals

1 to 2 for resistance.

• SPECIFIED VALUE: 1 – 5 Ω (@ 25° C).
– Was Value obtained?

– YES:

♦ GO TO: Step 3 

⇒ page 514

 .

– NO:

♦ REPLACE: Oxygen Sensor 1 After Catalytic

Converter - GX7- . Refer to appropriate repair

manual.

♦ GO TO: Step 8 

⇒ page 515

 .

3

• IGNITION: ON
• CHECK: Oxygen Sensor 1 After Catalytic Con‐

verter - GX7- harness connector terminal 1 to

ground for voltage.

• IGNITION: OFF.
• SPECIFIED VALUE: Battery voltage.
– Was Value obtained?

– YES:

♦ GO TO: Step 4 

⇒ page 514

 .

– NO:

♦ PERFORM: Visual Inspection of wiring and

component.

♦ CHECK: Wiring for open, high resistance,

short or harness connector for damage, corro‐

sion, loose or broken terminals.

♦ REPAIR: Faulty wiring or connector.
♦ GO TO: Step 8 

⇒ page 515

 .

4

• RECONNECT: Oxygen Sensor 1 After Cata‐

lytic Converter - GX7- harness connector.

• CONNECT: Scan Tool.
• START: Engine and let Idle.
• Perform the function test located in diagnostic

mode 06. Refer to

⇒ “3.3 Diagnostic Modes 01 - 0A”, page 21

 .

• IGNITION: OFF.
• SPECIFIED VALUE: Mode 6 Pass.
– Were Values obtained?

– YES:

♦ GO TO: Step 5 

⇒ page 514

 .

– NO:

♦ GO TO: Step 6 

⇒ page 515

 .

5

• FAULT: Is intermittent.
• PERFORM: Visual Inspection of wiring and

component.

• CHECK: Wiring for open, high resistance,

short or harness connector for damage, corro‐

sion, loose or broken terminals.

• REPAIR: Faulty wiring or connector.

♦ GO TO: Step 8 

⇒ page 515

 .

GTI 2014 ➤

Generic Scan Tool - Edition 04.2015

514

     Rep. Gr. ST - Generic Scan Tool

Step

Procedure

Result / Action to Take

6

• DISCONNECT: Oxygen Sensor 1 After Cata‐

lytic Converter - GX7- harness connector.

• IGNITION: ON.
• CHECK: Oxygen Sensor 1 After Catalytic Con‐

verter - GX7- component connector terminals

3 to 4 for voltage.

• IGNITION: OFF.
• SPECIFIED VALUE: 0.0 V to 1.0 V.
– Was Value obtained?

– YES:

♦ GO TO: Step 7 

⇒ page 515

 .

– NO:

♦ PERFORM: Visual Inspection of wiring and

component.

♦ CHECK: Wiring for open, high resistance,

short or harness connector for damage, corro‐

sion, loose or broken terminals.

♦ REPAIR: Faulty wiring or connector.
♦ GO TO: Step 8 

⇒ page 515

 .

7

• REMOVE: Engine Control Module - J623- .

Refer to appropriate repair manual.

• CHECK: Oxygen Sensor 1 After Catalytic Con‐

verter - GX7- harness connector terminal 2 to

the Engine Control Module - J623- harness

connector T91 / 11 for resistance.

• CHECK: Oxygen Sensor 1 After Catalytic Con‐

verter - GX7- harness connector terminal 3 to

the Engine Control Module - J623- harness

connector T91 / 26 for resistance.

• CHECK: Oxygen Sensor 1 After Catalytic Con‐

verter - GX7- harness connector terminal 4 to

the Engine Control Module - J623- harness

connector T91 / 25 for resistance.

• SPECIFIED VALUE: 0.5 Ω ( ± 0.3 Ω ).
– Were Values obtained?

– YES:

♦ GO TO: Step 8 

⇒ page 515

 .

– NO:

♦ PERFORM: Visual Inspection of wiring and

component.

♦ CHECK: Wiring for open, high resistance,

short or harness connector for damage, corro‐

sion, loose or broken terminals.

♦ REPAIR: Faulty wiring or connector.
♦ GO TO: Step 8 

⇒ page 515

 .

8

• Final Procedure
• Perform a road test to verify repair.
– Does the original DTC return?

– YES:

♦ CHECK: Engine Control Module - J623- har‐

ness connector for any damaged, pushed-out

pins.

♦ REPAIR: As necessary.
♦ Clear the DTC’s. Refer to

⇒ “3.3.4 Diagnostic Mode 04 - Erase DTC

Memory”, page 26

 .

♦ Repair is complete. Generate Readiness

Code. Refer to

⇒ “3.2 Readiness Codes”, page 19

 .

♦ Return vehicle to Customer.
♦ If all electrical connections are OK:
♦ REPLACE: Engine Control Module - J623- .

Refer to appropriate repair manual.

♦ Repair is complete. Generate Readiness

Code. Refer to

⇒ “3.2 Readiness Codes”, page 19

 .

♦ Return vehicle to Customer.
– NO:

♦ Perform the diagnostic procedure for any

DTC’s.

♦ If no DTC’s return the repair is complete.
♦ Return vehicle to customer.

GTI 2014 ➤

Generic Scan Tool - Edition 04.2015

3. Diagnosis and Testing    

515

3.6.28

Oxygen Sensor 1 Before Catalytic Con‐

verter - GX10- , Checking

General Description
The Oxygen Sensor 1 Before Catalytic Converter - GX10- does

not actually measure oxygen concentration, but rather the differ‐

ence between the amount of oxygen in the exhaust gas and the

amount of oxygen in air. Rich mixture causes an oxygen demand.

This demand causes a voltage to build up, due to transportation

of oxygen ions through the Oxygen Sensor 1 Before Catalytic

Converter - GX10- layer. Lean mixture causes low voltage, since

there is an oxygen excess. The Oxygen Sensor 1 Before Catalytic

Converter - GX10- and catalytic converters are used in order to

reduce exhaust emissions. Information on oxygen concentration

is sent to Engine Control Module - J623- , which adjusts the

amount of fuel injected into the engine to compensate for excess

air or excess fuel. The Engine Control Module - J623- attempts

to maintain, on average, a certain air–fuel ratio by interpreting the

information it gains from the Oxygen Sensor 1 Before Catalytic

Converter - GX10- . The primary goal is a compromise between

power, fuel economy, and emissions. The heater for Oxygen

Sensor 1 Before Catalytic Converter - GX10- is designed to min‐

imize the time-to-readiness for closed-loop operation by heating

the Oxygen Sensor 1 Before Catalytic Converter - GX10- as

quickly as possible.
Note the Oxygen Sensor 1 Before Catalytic Converter - GX10- is

also referred to as the Heated Oxygen Sensor - G39- .
The Oxygen Sensor 1 Before Catalytic Converter - GX10- con‐

tains the following components:
♦ Oxygen Sensor Heater - Z19-
♦ Heated Oxygen Sensor - G39-
The Oxygen Sensor 1 Before Catalytic Converter - GX10- com‐

ponents cannot be serviced separately, and must be serviced as

a unit.
Special tools and workshop equipment required
♦ Multimeter.
♦ Wiring Diagram.
♦ Scan Tool.
Test requirements
• Fuses OK.
• Battery voltage OK.
• Switch OFF all electrical and electronic accessories.
• Vehicles with Auto. Transmission, ensure Selector Lever po‐

sition is in “P”.

• Vehicles with Man. Transmission, ensure Shifter Lever posi‐

tion is in “N” with Parking Brake applied.

• Coolant Temperature: ≥ 80° C.
• Observe all safety precautions:

⇒ “1.1 Safety Precautions”, page 2

 .

• View clean working conditions:

⇒ “1.2 Clean Working Conditions”, page 3

 .

• For Hybrid vehicles refer to:

⇒ “1.3 High Voltage System General Warnings”, page 4

 .

GTI 2014 ➤

Generic Scan Tool - Edition 04.2015

516

     Rep. Gr. ST - Generic Scan Tool