Audi A3 1997 - Checking Function of Electrical Additional Heater; Servicing Electrical Additional Heater - Vehicles with TDI Engine

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
with respect to the correctness of information in this document. Copyright by AUDI AG.
◆ The heat exchanger has been installed in vehicles with map-controlled cooling (to be introduced gradually
as of model year 1999 vehicles with 1.6 l engine) which has been adapted to the different usage conditions.
The following must be noted for this heat exchanger:
- -> The flow direction of the refrigerant in the heat exchanger is not marked at the refrigerant connections
(observe feed and return flow).
- The heat exchanger components carrying refrigerant are produced entirely from metal due to the higher
feed refrigerant temperature.
=> Parts List
4 - Servicing electrical additional heater - Vehicles with TDI engine
4.1 - Servicing electrical additional heater - Vehicles with TDI engine
4.2 - 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
- -> Check earth wiring to refrigerant stump -A- (in which the glow lamps are screwed into) to the cylinder
head.
Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
3.2 - Removing and installing heating system heat exchanger 123