SEAT Workshop Service and Repair Manuals

Engine speed sender -G28-: checking

Special tools and workshop equipment required

t	Manual multimeter -VAG 1526B-

t	Measuring tool set -VAG 1594C-

t	Tester -VAG 1598/31-

t	Current flow diagram

Note The Engine speed sender -G28- is a speed and reference mark sender. The engine will not start without the signal from the engine speed sender -G28- If the speed signal fails when the engine is running, the engine stalls. Fitting location: → Item. Test sequence –  Before performing check, verify that the sender is properly fitted and fixed.

–  Separate grey 3 pin connector -arrow- to engine speed sender. –  Measure the resistance of the sender between contacts “2”+“3” of connector to sender.

Specification: 730 ... 1000 Ω.   Note The resistance value of the engine speed sender refers to a temperature of 20 °C. The resistance rises when the temperature increases. If specification is not attained: –  Replace the engine speed sender -G28-. If the specified value is achieved:

–  Adjust the multimeter to measure resistance and connect between contacts “2” and “1” (screening), as well as between contacts “3” and “1” (screening). Specification: ∞ Ω (no continuity). If specification is not attained: –  Replace the engine speed sender -G28-. If the specified value is achieved:

–  Connect tester -VAG 1598/31- to control unit cable harness, without connecting engine control unit → Chapter.

–  Check cables between tester box and 3-pin connector for open circuit, short circuit to earth or to positive:

Connector, contact	Tester -VAG 1598/31-, socket
1 (shielding)	108
2 (earth)	90
3 (signal)	82
Specification: 1,5 Ω max.

–  Also check cables for short circuits between them. If no wiring fault is detected: –  Replace engine control unit: → Vehicle diagnosis, testing and information system VAS 5051.