CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – 019-390   Turbocharger Speed Sensor

The turbocharger speed sensor is located on the top of the turbocharger between the compressor and the turbine housings. The electronic service tool can be used to monitor the sensor for proper operation.

CAUTION  When removing the turbocharger speed sensor, use a twisting motion while pulling upward. Prying on the sensor body with a screwdriver can lead to broken sensors and could result in unwarranted turbocharger replacement. Pliers are recommended for turbocharger speed sensor removal.

Lift up on the locking tab and pull the electrical connectors apart. Remove the mounting capscrew.

Use pliers to remove the turbocharger speed sensor, use a twisting motion while pulling upward.

Inspect the turbocharger speed sensor body for signs of melting or damage. If signs of melting or damage are found on the sensor, inspect turbocharger coolant supply for restriction.

If the turbocharger speed sensor is being removed due to an oil leak, inspect the turbocharger speed sensor o-ring for signs of damage.  If the o-ring is cut or damaged, the o-ring must be replaced.

If there are no cuts or damage evident to the o-ring, it is possible to reseal and prevent oil leaks.  To do this, apply Loctite™ 5699, or equivalent, to the o-ring and the area where the o-ring sits on the speed sensor, prior to assembly.

If installing a new turbocharger speed sensor, make sure the new turbocharger speed sensor has a new o-ring installed.

If the turbocharger speed sensor was removed due to an oil leak, it is possible to reuse the turbocharger speed sensor and either replace or inspect the o-ring for reuse (as described in the Inspection section above).

Apply Loctite™ 5699, or equivalent, to the o-ring.  This helps seal and prevent oil leaks.

Install the turbocharger speed sensor into the engine.

Apply Loctite™, Part Number 3824040, onto the capscrew.

Install the capscrew and tighten.

CAUTION  The turbocharger speed sensor harness must be tied up and away from any heat sources and hard or sharp surfaces. Failure to do so will cause damage to the harness.

CAUTION  Do not install cable ties directly over the sensor connector. Doing so can damage the connector. Tie the speed sensor wiring harness on either side of the connectors.

Use cable ties to secure the harness to the turbocharger actuator harness.

Be sure to p-clip the turbocharger speed sensor wiring harness to the stud located on the bottom of the ISM air compressor inlet connection at the mixer.

Push the connectors together until they lock.

The connector must be fully engaged.

Start the engine and verify with the electronic service tool that the turbocharger speed sensor is working properly.