Checking CO2 level in additional heater exhaust gas (heater with no recirculating pump -V55) — AUDI

Notes:

Additional heater is switched on by way of fault reader V.A.G 1551 (basic setting function, display group number 022 =>Page
01-81
).
In the case of heaters with control unit -J162 as of software version "D49", auxiliary/additional heater can be operated by way of "basic setting" function up to a coolant temperature of 115° C. Starting from control interval is possible. The operating time is limited to max. 8 minutes.
Heed test requirements =>Page
82-93
.

Start auxiliary/additional heater self-diagnosis => Page
01-22
.
Interrogate fault memory =>Page
01-40
and eliminate any faults displayed.

Erase fault memory =>Page
01-88
.
Switch on exhaust analyzer V.A.G 1788 and insert corresponding hose of exhaust probe into exhaust pipe -A- of additional heater.

Note:

Exhaust probe must not impede emergence of exhaust gas from exhaust pipe during test.

Start engine.
Set operating and display unit for air conditioner/Climatronic -E87 to maximum heat output (temperature preselection "Hi").
Start auxiliary/additional heater self-diagnosis and switch on additional heater by way of "basic setting" function => Page
01-69
.
Wait until additional heater switches from starting to full load mode (roughly 4 minutes, interrogate instantaneous operating status =>Reading measured value block, Page
01-106
).
Allow additional heater to run in full load mode for at least 1 minute.

Read off measured value for CO2 (carbon dioxide) level in exhaust gas from CO2 measuring instrument (as of approx. 5 minutes after switch-on; additional heater must be in full load mode).

Specifications:

Diesel engine
8 to 13 % by vol. CO2

Notes:

If measured value is outside permitted range:
Check combustion air blower intake area and additional heater exhaust system for dirt and clean if necessary.
Check fuel delivery => Page
82-76
.

If CO2 level in exhaust gas and metering pump delivery rate are in lower specified range:
Replace metering pump -V54 => Page
82-86
.

If CO2 level in exhaust gas is not OK although fuel delivery is:

Check air intake hose (with intake silencer) and additional heater exhaust system and service if necessary. If no fault is found:

In the case of additional heater with control unit with software version "X46", "D47" or "D48" (CO2 level in exhaust gas not adjustable):
Check combustion air blower -V6.
Replace additional heater with combustion air blower -V6
=> Page
82-171
.

In the case of additional heater with control unit with software version as of "D49" (CO2 level in exhaust gas adjustable):
Check combustion air blower -V6.
Adjust CO2level in exhaust gas => Page
82-108
.
If CO2level in exhaust gas cannot be adjusted, replace combustion air blower -V6 => Page
82-171
.

In the event of additional heater starting problems although fuel delivery OK:
Check glow plug with flame monitor -Q8 => Page
01-153
.
Remove residue from burner element (only applies to operation with vegetable oil methylester fuel) => Page
82-113
.
Replace burner element => Page
82-167
.