A3 Quattro V6-3.2L (BUB) (2008)
Main Relay (Computer/Fuel System): Testing and Inspection
Motronic Engine Control Module
Motronic Engine Control Module (ECM) J220 regulates fuel injection, Throttle Valve Control Module J338, oxygen sensor regulation, ignition, knock
control, Evaporative Emission (EVAP) Canister Purge Regulator Valve N80, engine speed limitation through fuel injectors or Fuel Pump (FP) Relay J17
as well as On Board Diagnostic (OBD).
Motronic Engine Control Module Voltage Supply, Checking
Special tools, testers and auxiliary items required
-
Multimeter.
-
Wiring diagram.
Test requirements
-
The Motronic Engine Control Module (ECM) J220 fuses OK.
-
Battery voltage at least 12.5 volts.
-
All electrical consumers such as, lights and rear window defroster, switched off.
-
Vehicles with automatic transmission, selector lever in position "P" or "N".
-
A/C switched off.
-
Ground (GND) connections between engine/transmission/chassis OK.
-
Ignition switched off.
Test procedure
-
Perform a preliminary check to verify the customers complaint. See: Powertrain Management/Computers and Control Systems/Testing and
Inspection/Initial Inspection and Diagnostic Overview/General Diagnosis
Start diagnosis
-
Remove the Motronic Engine Control Module (ECM) Power Supply Relay J271.
Checking voltage
-
Using a Multimeter, check the Motronic Engine Control Module (ECM) Power Supply Relay J271 socket 1/30 to Ground (GND).
Specified value: battery voltage.
If the specified value was not obtained:
-
Check the wiring connections from the Battery to the Motronic Engine Control Module (ECM) Power Supply Relay J271 socket 1/30 for an open
circuit or a short circuit.
-
Check the wiring connections for damage, corrosion, lose or broken terminals.
-
If necessary, repair the faulty wiring connection.
If the specified value was obtained:
-
Switch the ignition on.
-
Using a Multimeter, check the Motronic Engine Control Module (ECM) Power Supply Relay J271 socket 3/86 to Ground (GND).
Specified value: battery voltage.
If the specified value was obtained:
Checking wiring