Servicing Electrical Additional Heater - Vehicles With Tdi Engine 06.94 Ä; Checking Function Of Electrical Additional Heater - Audi A3 1997 Manual

Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
8 - Servicing electrical additional heater - Vehicles with TDI engine 06.94 ä
8.1 - Servicing electrical additional heater - Vehicles with TDI engine 06.94 ä

8.2 - Checking function of electrical additional heater

Electrical additional heater is activated by control unit for diesel direct injection system -J248 when following
conditions occur at the same time:
◆ measured ambient or intake pipe air temperature (when engine starts) lower than 5 °C
◆ Refrigerant temperature less than 70 °C
◆ Engine speed above 800 rpm
◆ Other actuation conditions:
=> Relevant Workshop Manual Diesel Direct Injection and Preglow System; Repair group 01; Reading meas‐
ured value block
Test sequence
- Check low heating output relay -J359 or high heating output relay -J360:
=> Relevant Workshop Manual Diesel Direct Injection and Preglow System; Repair group 01; Final control
diagnosis
If the relays are OK:
- Test wiring for open circuit and short to positive or earth.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
- -> Check earth wiring to refrigerant stump -A- (in which the glow lamps are screwed into) to the cylinder
head.
If no wiring fault in earth wiring is detected:
- Check glow plugs:
- Remove the electrical wiring -B- from the glow plugs.
- Connect multimeter for resistance measurement to the glow plug and measure resistance between glow
plug and refrigerant stud -A-.
- Specified value: 0.5 ... 0.7 ωat room temperature
If specified value is not attained:
- Replace glow plug.
- Check refrigerant level:
190
87 - Air conditioning
with respect to the correctness of information in this document. Copyright by AUDI AG.