Toronado V6-3800 3.8L (1988)
Oil Level Sensor: Customer Interest
Low Oil Level Sensor - False Warning Message
SUBJECT
LOW OIL LEVEL MESSAGE OPERATION
(DIAGNOSIS AND NEW OIL LEVEL SENSOR AND OIL PAN RELEASED)
MODELS/YEARS
1988-90 TORONADO AND TROFEO
NUMBER:
90-T-179
CORP.REF.NO: 918108R
DATE:
November 1990
SECTION:
8D2
Some 1988-1990 Toronados and Trofeos may exhibit an intermittent, false low oil level warning message due to either an inoperative oil level sensor or
a misformed oil pan.
IMPORTANT:
1.
Some customers may confuse oil pressure warnings wfth low oil level messages. It is critical to identify which oil warning message (pressure or
level) was displayed before attempting to repair an oil warning condition.
2.
With either an oil level sensor inoperative all the time or a misformed oil pan, the message will appear to be intermittent because of the way that
the oil level is tested by the body computer. See "Oil Level Sensor System Operation", which follows.
A new sensor, P/N 1649745, has been released. The new sensor requires a gasket or seal which must be ordered separately as P/N 25531045. The seal
must be replaced whenever a sensor is replaced.
A new oil pan has been released for service on cars with 3800 (LN3) VIN C engines. The new pan requires a new gasket, oil pump screen, oil pump
screen gasket, and dipstick. These parts can be ordered through GMSPO as a kit using P/N 12350269.
TO DIAGNOSE LOW OIL LEVEL MESSAGES:
1.
Check the oil level using the dipstick.
2.
Turn the key to "ON" with the engine off. If the engine has been running, allow time for the oil to drain back into the oil pan.
3.
Enter service diagnostics and monitor BCM Input BI88. If the input is "HI", go to 4A. If the input is "LO", go to 4B.
4A.
If value reads "HI" with oil level OK, disconnect the oil level sensor connector and jumper the harness
terminals together.
^
If the BI88 changes to "LO":
For 1988 Toronado's/Trofeo's; replace the sensor.
1989-1990 Toronado's/Trofeo's; replace the oil pan, oil pump screen, dipstick, and sensor.
^
If the BI88 changes remain "HI" with the terminals jumpered, check for an open in circuit 114 from the BCM to the sensor; and check the
sensor ground circuit for continuity to ground. Repair any wiring faults found and reconnect the sensor. (Go back to step 3.)
4B.
If value reads "LO" with oil level OK (possible intermittent sensor or wiring).
^
In Diagnostics, monitor BI88 while moving the wiring and connectors between the oil level sensor and the BCM. Any open circuit between
the sensor and BCM or between the sensor and ground will cause the oil level input to be "HI" and could cause a false low oil level
message. The X/O status indicator will change from 0 to X if an open occurs.
IMPORTANT:
Due to oil splash the sensor input will change from low to high while driving. This is a normal condition. Perform tests for
intermittent sensors at key on, engine off.
OIL LEVEL SENSOR SYSTEM OPERATION:
With proper oil level, the BI88 should be "LO". (The sensor grounds the 5 volt circuit from the BCM when oil level is OK; a ground on the circuit is
"LO" in diagnostics.)
