ISM, ISMe, and QSM11 – 011-009   Exhaust Restriction

For CM871 and CM876 engine remove the aftertreatment diesel oxidation catalyst inlet temperature sensor from the aftertreatment inlet and disconnect it from the wiring harness. Install the pressure gauge adapter, Part Number 4918576. Connect a manometer or pressure gauge, Part Number ST-1273, to the pressure gauge adapter.

Protect the hose from heat by using a 305 mm [12 in] minimum length of metal tubing leading from the exhaust pipe connection.

NOTE: Disconnecting the aftertreatment diesel oxidation catalyst inlet temperature sensor will trigger Fault Code 1666. Do not troubleshoot this fault code during this exhaust restriction measurement.

Operate the engine at rated rpm and load. Record the reading on the manometer.

Exhaust Restriction

If the exhaust pressure exceeds the specifications, inspect the exhaust piping for damage. Refer to the OEM troubleshooting and repair manual.

If the vehicle is equipped with an aftertreatment system, inspect the aftertreatment system for a plugged aftertreatment diesel particulate filter and/or a plugged aftertreatment diesel oxidation catalyst.

Extended engine operation with high exhaust restriction can lead to damaged turbocharger oil seals. Refer to Procedure 010-033 to inspect the turbocharger for progressive damage.

Remove the test equipment and install the aftertreatment diesel oxidation catalyst inlet temperature sensor. Operate the engine and verify that all fault codes are inactive.