Usage:
3176 (2YG, 7LG) Truck Engines
Recently several Electronic Control Module (ECM) failures and repeat failures have been traced to moisture entry through the inlet air hose (Atmospheric hose) connected to the transducer module. The root cause of the moisture entry has been due to the following:
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- * The inlet air hose is routed near the exhaust manifold. This causes the hose to burn or rub open.
- * The inlet air hose fittings are not tight from the truck manufacturer or after repair.
- * The air filter service indicator hose is rubbed open on the vehicle hood. This hose is teed into the inlet air hose that leads to the transducer module.
- * The air filter service indicator is cracked.
- * There are damaged or missing O-ring seals on the personality module or transducer module.
- * The inlet air hose is routed near the exhaust manifold. This causes the hose to burn or rub open.
NOTE: The previously listed failure modes are common problems found in the field. However, any damaged component in the inlet air hose system or in a connecting system may allow moisture entry. See the illustration.
Typical inlet air hose and components. (1) Air Filter Service Indicator. (2) Air Filter/Air Piping. (3) Air Filter Service Indicator Hose. (4) ECM. (5) Transducer Module. (6) Personality Module. (7) Inlet Air Hose. (8) Boost Hose (routed to top of inlet manifold).
The previously listed failure modes can allow water, corrosive spray wash, etc. to collect inside the hose. From there, the moisture can pass into the transducer module, ECM, and personality module. Moisture entry into the electronic controls may cause intermittent engine shutdown and/or erroneous fault codes.
Proper inspection and maintenance of the inlet air hose, air filter service indicator hose, air filter service indicator, hose connections, and other connected components is a MUST.
If moisture entry is suspected, remove the personality module and/or transducer module and inspect for moisture entry. Signs of moisture are beads of water, rust on screw heads, white residue buildup, or corrosion of the transduce module-to-ECM 5 pin connector.
If moisture entry has occurred FIND THE ROOT CAUSE and REPAIR. Refer to the previously listed possible causes and the illustration. After the root cause is repaired, the ECM, personality module, and transducer should be replaced.
NOTE: Failures due to moisture entry are NOT the responsibility of Caterpillar. Caterpillar is responsible for proper personality module/transducer module O-ring installation. The truck manufacturer is responsible for hose and service indicator installation. Customers are responsible for proper system maintenance.