Volkswagen Golf / Golf GTI / Jetta. Manual — part 173

01-234

Display group 46 - Oxygen Sensor (O2S) control - Three Way Catalytic Converter
(TWC) diagnosis (conversion test)

Control module in function "04-Basic setting"

Vehicle stationary, engine running at increased idle speed (only with depressed

brake pedal and accelerator)

System in basic
setting 46

Indicated on display

xxxx
rpm

xxx.x

C

x.xx Text

1

2

3

4

Display zones

Specification

Evaluation

Result of Three Way
Catalytic Converter (TWC)
conversion test

(Test OFF / Test ON /
CatB1 OK. / CatB1n.OK.)

CatB1 OK.

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235

Three Way Catalytic Converter
(TWC) conversion rate

0.00...0,99

---

Three Way Catalytic Converter (TWC)
temperature

min. 380.0 C

---

Engine speed

Approx. 2300

rpm

---

Note on display zone 2:

Value calculated from engine speed and engine load.

Measured value (data) blocks

01-235

Evaluating display group 46, display zone 4 - Three Way Catalytic Converter (TWC)
diagnosis (conversion test)

Appears on display

Possible cause

Corrective action

Three Way Catalytic
Converter (TWC) not
OK.: Cat B1 nOK.

DTC stored in DTC

memory

- Check DTC memory

Page 01-

23

, DTC memory, checking and

erasing

Three Way

Catalytic Converter
(TWC) faulty

Repair Manual, 2.8 Liter VR6 4V

Engine Mechanical, Engine Code
(s): BDF; Repair Group 26

- Perform road test at a constant
speed

- Perform diagnosis again if result
is same:

- Replace Three Way Catalytic
Converter (TWC):

Measured value (data) blocks

01-236

Display group 99 - Oxygen Sensor (O2S) control - Oxygen Sensor (O2S) control
operating condition

Engine running at idle

Control module in function "04-Basic setting", Oxygen Sensor (O2S) control off

Control module in function "08-Read measured value block", Oxygen Sensor

(O2S) control on

System in basic
setting 99

Read measured
value block 99

Indicated on display

xxxx
rpm

xxx.x

C

x.xx Text

1

2

3

4

Display zones

Specification Evaluation

Oxygen Sensor (O2S)
control operating
condition:

in function "04"

in function "08"

-Reg. ON

-Reg. ON

---

Oxygen Sensor (O2S) control,
current value

0,96...1.04

---

Coolant temperature

80.0...110.0

C

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195

Engine speed (idle speed)

640...720 rpm

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188

Notes on display zone 4:

For a defined fault finding the Oxygen Sensor (O2S) control is switched off when

selecting display group 99 under "04-Basic setting" or switched on under "08-Read
measured value block". When the function "04-Basic setting" is exited the Oxygen
Sensor (O2S) control is automatically active again.

It is possible to switch between the function "04-Basic setting" and the function "08-

Read measured value block" by pressing the buttons 4 and 8 on VAG 1551/1552.

Measured value (data) blocks

01-237

Measured value blocks, display groups 50...69 - Speed control,
Evaluating

Display group 50 - Speed control - Operating condition

Engine running at idle

Read measured value
block 50

Indicated on display

xxxx
rpm

xxxx
rpm

Text Text

1

2

3

4

Display zones

Specification Evaluation

Air conditioning
compressor operating
condition

(Compr. ON / Compr.
OFF)

Compr. ON or

Compr. OFF

---

Air conditioning operating
condition

(A/C-High / A/C-Low)

A/C-High or

A/C-Low

---

Engine speed (specified idle speed)

700 rpm

---

Engine speed (actual idle speed)

640...720 rpm

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188

Notes on display zones 1 and 2:

The rpm in display zone 1 (measured rpm) is the actual engine speed.

The rpm in display zone 2 (specified rpm) is theoretical engine speed calculated by

the Motronic Engine Control Module (ECM) -J220-. at idle, the Motronic Engine
Control Module (ECM) -J220- always tries to adapt the actual engine speed to the
specified engine speed.

Notes on display zones 3 and 4:

A/C-High = Air conditioner demands high heating or cooling performance. A/C-Low = Air
conditioner not turned on.

"Compr. OFF" is always displayed on vehicles with no air conditioner.

Check signals to and from air conditioning

Page 24-194

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Measured value (data) blocks