90 Quattro 20V L5-2309cc 2.3L DOHC (7A) (1990)
/Page-1997001.png)
Ignition Hall Effect Sensor: Testing and Inspection
Models Produced Up to March 1990
This test requires that the battery is fully charged and battery voltage does not drop below 9 volts while cranking.
1.
Remove distributor end of coil wire from distributor cap and ground it to the engine.
MPI Hall Sensor Connector
2.
Disconnect hall sensor harness connector from side of distributor.
3.
Turn ignition "on" and check voltage between hall sensor harness connector terminals #1 (ground, Brn/W wire) and #3 (power from ECU,
Red/BLK wire).
^
Voltage should be 9-11 volts. If not, check for:
a. Open or grounded circuit between ECU terminal 1B and distributor harness connector terminal #3
b. Open circuit between distributor harness connector terminal #1 and ECU terminal 23B.
c. No battery power to ECU terminal 18A &/or 25A.
d. Engine ground circuits from ECU terminals 1A, 2A, 13A, &/or 21A (poor connections or open circuit).
Repair as necessary. If no problems are found in wiring, and there is still no voltage present at hall sensor terminal #3, then the ECU is faulty. If voltage
is present, continue with test.
4.
Slide rubber boot away from distributor harness connector to gain access to the back of the connector terminals, and re-connect to distributor.
5.
Connect LED test light between terminals #1 (sensor ground) and #2 (hall signal) of distributor connector.
6.
Crank engine and observe LED.
^
LED should flash once every two crankshaft revolutions while cranking (when connected with proper polarity). If not, check for:
a. Open circuit between distributor harness connector terminal #1 and ECU connector terminal 23B.
If there is no wiring problem, hall sensor is faulty and must be replaced.
If LED does flicker, hall sensor is OK.
If hall sensor checks OK and fault code 2113 was displayed, check for:
a. Open or grounded circuit between distributor harness connector terminal #2 (Grn/W wire) and ECU terminal 11B.
DYNAMIC TEST
Hall Sensor Signal
