Allison B 300, Руководство по устранению неисправностей

Страница: 61 / 396

Copyright © 1998 General Motors Corp. 6–25
W T E C I I E L E C T RO N I C C O N T RO L S T RO U B L E S H O OT I N G M A N UA L
Code 14 12 indicates the ECU has detected a voltage signal in the low error zone.
Code 14 12 can be caused by:
• Faulty wiring to the OLS
•
A faulty OLS
• A faulty ECU
OLS ground wire 135B is common to the TPS and the RMR devices. A power wire short-to-ground for any of
these devices will cause “sensor failed low” codes (21 12 and 64 12). An OLS signal open or short-to-ground
results in a Code 14 12 only. Code 14 23 is programmed out of all calibrations.
A permanent maximum voltage signal generates a steady OLS sensor maximum count and a maximum fluid level
overfill indication. A maximum overfill indication occurs if signal wire 165 or power wire 106 are shorted to
battery or the ground wire (wire 135). An open in the ground circuit wire 135 in the portion common to the OLS,
TPS and RMR devices results in Code 14 12, 21 23, and 64 23.
If the ECU software supports it, Oil Level Sensor counts can be read by a DDR with Pro-Link
®
version 3.0 (or
later). For complete description of oil level checking procedures using the oil level sensor, see Section 5. Normal
operation of the OLS can be checked as follows: Attach the DDR and display OIL LEVEL COUNTS. Read the
number of counts when the engine is not running, but the ignition is ON. The count reading should be near 255.
Start the engine and observe the counts. In normal operation, the count should be 100–200 because the oil level
drops when the engine starts and oil from the sump is delivered to other parts of the transmission.
NOTE: Intermittent connections or lack of battery-direct power and ground connections can cause this and
other electronic control codes.
Active Indicator Clearing Procedure:
• Power down
•
Manual
• Self-clearing
NOTE: Before troubleshooting, read Pages 6–17 and 6–18 of Section 6–5. Also, check the following:
• Fluid level, using dipstick
• Battery voltage
• ECU input voltage
• Other diagnostic codes
CAUTION:
Never use a Volt-Ohmmeter to measure any parameters on the OLS. Damage to the OLS
will result.
Main
Code
Subcode Meaning
14 12 Oil level sensor failed low
14 23 Oil level sensor failed high (not used)
CODE 14 XX — OIL LEVEL SENSOR (OLS) (Figures 6–3, 6–4)