6–26 Copyright © 1998 General Motors Corp.
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
Troubleshooting:
The following procedure is to find the cause for an OLS problem. The procedure is sequential. Follow the
procedure until the cause for the OLS problem is found and repaired. Once the problem is found and repaired,
STOP. For example, if the problem is fixed in Step 3, there is no need to continue to the other steps.
1. Disconnect the external wiring harness at the transmission feedthrough connector. With the
ignition ON, verify there is 5.0VDC between the OLS power and ground pins (see Page D–8 or
D–9) on the external harness connector. This is to verify that power and ground are getting to the
OLS. If 5.0VDC is not present, check the wiring for the OLS power and ground circuits (wires 124
and 135, respectively). If there are no wiring problems (opens, shorts-to-ground, shorts-to-battery),
and if 5.0VDC is present, go to Step 2.
2. Observe the OIL LEVEL COUNTS on the DDR while jumpering the OLS power pin to the OLS
signal pin. If the count jumps from 0 to 250+, the OLS signal line is good and the ECU function is
good. Continue to Step 3. If the count remains at zero, locate and repair problems in the wiring of
OLS signal (wire 165). If there are no wiring problems, and the count still remains at zero, the
ECU may be bad. Go to Step 5.
3. If all checks prior to this have been normal, the problem is either in the OLS itself, the internal
harness wires, or the transmission side of the feedthrough harness connection. Inspect the
transmission feedthrough harness connector to be sure that the OLS power, ground, and signal pins
are not loose or out of position. Correct any connector problems found. Reconnect the external
harness to the transmission feedthrough harness connector. See if Code 14 12 recurs before
continuing to Step 4.
4. Consult the appropriate transmission Service Manual for proper procedure and remove the control
module from the transmission. Remove the OLS from the channel plate. Reconnect the external
harness to the transmission feedthrough connector, if not done in Step 3. With the ignition ON,
observe OIL LEVEL COUNTS on the DDR. With the OLS in normal position, the count should
be 8–35. Invert the OLS and the count should be 192–255. If the counts are abnormal, replace the
sensor. Check the new sensor in both normal and inverted positions. If the counts respond
correctly, the problem should be resolved. Attach the new OLS to the channel plate and reinstall
the control module using the appropriate transmission Service Manual for proper procedure.
5. Replace the ECU. If replacing the ECU corrects the problem, reinstall the original (bad) ECU to
confirm that the problem is in the ECU. If the original ECU now works, inspect the ECU
connectors for any corrosion or damage which may cause an intermittent condition. If the original
problem recurs, reinstall the replacement ECU.
CODE 14 XX — OIL LEVEL SENSOR (OLS) (Figures 6–3, 6–4)
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