For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Boost Pressure Actuator is an electrically operated DC motor designed to regulate the boost pressure output of the Turbocharger. The Boost Pressure Actuator is mounted to the side of the Turbocharger assembly. The Boost Pressure Actuator receives 12 Volts from the Totally Integrated Power Module (TIPM) and a duty-cycle control signal from the Powertrain Control Module (PCM). When this fault is active the EGR System, DPF Regeneration, and Boost Pressure Actuator are disabled. The engine will also experience a torque reduction.
When Monitored:
With the ignition on and the Boost Pressure Actuator command off.
Set Condition:
The Powertrain Control Module (PCM) detects that the (X635) Boost Pressure Actuator Control circuit voltage is low for 0.5 second.
Repair the (F344) Fused ASD Relay 2 Output circuit for an open or high resistance. Inspect the related fuse, an open fuse may indicate a short to ground in the circuit.
4.
CHECK THE (X635) BOOST PRESSURE ACTUATOR CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1.
Measure the resistance of the (X635) Boost Pressure Actuator Control circuit between the Boost Pressure Actuator harness connector and the PCM C1 harness connector.
Reconnect the Boost Pressure Actuator harness connector.
2.
Reconnect the PCM C1 harness connector.
3.
Turn the ignition on.
4.
With the scan tool, erase DTCs.
5.
Turn the ignition off.
6.
Disconnect the Boost Pressure Actuator harness connector.
7.
Connect a jumper between the (X635) Boost Pressure Actuator Control circuit and the (F342) Fused Ignition Switch Output circuit at the Boost Pressure Actuator harness connector.
8.
Turn the ignition on.
9.
With the scan tool, view DTCs.
NOTE:
The scan tool should display a P0048-Turbocharger Boost Control Circuit High DTC with the jumper in place.
Did the scan tool display the DTC as described above?
Yes
Replace the Turbocharger Assembly in accordance with the service information.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Boost Pressure Actuator and the Powertrain Control Module (PCM).
2.
Look for any chafed, pierced, pinched, or partially broken wires.
3.
Look for broken, bent, pushed out or corroded terminals.
4.
Perform any Technical Service Bulletins that may apply.
