APRILIA Tuono V4 1100 Factory Service Station Manual page 193

Tuono V4 1100 Factory
•
open circuit, short circuit to positive / short circuit to negative
Error cause
•
If open circuit, short circuit to positive: an excessive voltage was detected at PIN 37 of the
ENGINE connector. If short circuit to negative: zero voltage detected. The instrument panel
indicates this error by lighting up in a fixed manner the MI warning light.
Troubleshooting
•
If open circuit, short circuit to positive: check the sensor connector and the Marelli control
unit connector. If they are OK, check sensor continuity: replace the sensor if not OK; if OK,
check continuity between the ENGINE connector PIN 37 and the sensor PIN 1: If continuity
is absent, restore the wiring harness; if ok reconnect the control unit connector and with key
ON check the continuity between PIN 2 of the sensor connector and vehicle ground: if OK,
it means that the error is caused by the cable being shorted to positive and it is necessary
to restore the cable harness between ENGINE PIN 37 and sensor PIN 1; check the sensor
connector and the Marelli control unit connector. If not OK, restore the cable harness. If OK,
check for continuity between the ENGINE connector PIN 6 or 17 and the sensor connector
PIN 2: restore the cable harness if there is no continuity. If there is, it means that the control
unit does not supply the ground connection and therefore should be replaced
•
If short circuit to negative, check the correct resistance of the sensor: if the resistance is null,
replace the sensor; if the resistance is correct, it means that the Grey cable has ground
connection: restore the cable harness
Lambda sensor
(FRONT CYLINDER BANK)
Function
In charge of telling the control unit whether the
mixture is lean or rich
Operation / Operating principle
The Marelli injection control unit reads and inter-
prets a voltage generated by the difference in oxy-
gen content between the exhaust fumes and the
ambient. It does not require an external supply
source but, in order to work properly, it should
reach a high operating temperature: that is why
there is a heating circuit inside
Level in electrical circuit diagram:
Lambda probe
Electrical system
ELE SYS - 193