For a complete wiring diagram Refer to Section 8WThe Boost Pressure Servo Motor is a electrically operated DC motor designed to regulate the boost pressure output of the turbocharger. The BPSM is mounted to the side of the turbocharger assembly. The BPSM receives 12–volt power, ground and a duty-cycle ground signal from the ECM. When Monitored:With the ignition on and the Boost Pressure Servo Motor command off.Set Condition:The ECM detects that the (K137) Boost Pressure Servo Motor Control circuit is open for 0.5 second.Possible CausesINTERMITTENT DTC(F344) FUSED ASD RELAY OUTPUT CIRCUIT OPEN OR HIGH RESISTANCE(K137) BOOST PRESSURE SERVO MOTOR CONTROL CIRCUIT SHORTED TO GROUND(K137) BOOST PRESSURE SERVO MOTOR CONTROL CIRCUIT OPEN OR HIGH RESISTANCEBOOST PRESSURE SERVO MOTORENGINE CONTROL MODULE (ECM)Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)1. DTC IS ACTIVEIgnition on, engine not running.With the scan tool, Clear DTCs in the Engine Control Module (ECM).With the scan tool, actuate the Boost Pressure Servo Motor at 100%.Monitor the scan tool for at least two minutes.With the scan tool, select View DTCs.Is the status Active for this DTC?YesGo To 2 NoRefer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)2. (F344) FUSED ASD RELAY OUTPUT CIRCUIT OPEN OR HIGH RESISTANCE

Turn the ignition off.Disconnect the Boost Pressure Servo Motor harness connector.Turn the ignition on.Using a 12 volt test light connected to ground, check the (F344) Fused ASD Relay Output circuit in the Boost Pressure Servo Motor harness connector.The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.Is the test light illuminated and bright?YesGo to 3NoRepair the (F344) Fused ASD Relay Output circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)3. (K137) BOOST PRESSURE SERVO MOTOR CONTROL CIRCUIT SHORTED TO GROUND

Turn the ignition off.Disconnect the Engine Control Module (ECM) harness connector.Measure the resistance between ground and the (K137) Boost Pressure Servo Motor Control circuit in the Boost Pressure Servo Motor harness connector.Is the resistance above 1000 ohms?YesGo to 4NoRepair the (K137) Boost Pressure Servo Motor Control circuit for a short to ground.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)4. (K137) BOOST PRESSURE SERVO MOTOR CONTROL CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K137) Boost Pressure Servo Motor Control circuit between the Boost Pressure Servo Motor harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms?YesGo to 5NoRepair the (K137) Boost Pressure Servo Motor Control circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)5. BOOST PRESSURE SERVO MOTOR

Turn the ignition off.Connect the Engine Control Module (ECM) harness connector.Turn the ignition on.With the scan tool, actuate the Boost Pressure Servo Motor (Boost Pressure Actuator) to 100%.Using a 12 volt test light connected to 12 volts, check the (K137) Boost Pressure Servo Motor Control circuit in the Boost Pressure Servo Motor harness connector.The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.The circuit will remain actuated by the controller for 30 seconds. Be certain the actuation is active when checking the circuit.With the scan tool, actuate the Boost Pressure Servo Motor (Boost Pressure Actuator) to 0%.Using a 12 volt test light connected to 12 volts, check the (K137) Boost Pressure Servo Motor Control circuit in the Boost Pressure Servo Motor harness connector.The test light should not be illuminated.The circuit will remain actuated by the controller for 30 seconds. Be certain the actuation is active when checking the circuit.Is the test light illuminated and bright with the actuation at 100% and not illuminated with the actuation at 0%?YesReplace the Boost Pressure Servo Motor in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 66. ENGINE CONTROL MODULE (ECM)Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Boost Pressure Servo Motor and the Engine Control Module (ECM).Look for any chafed, pierced, pinched, or partially broken wires.Look for broken, bent, pushed out or corroded terminals.Refer to any Technical Service Bulletins that may apply.Were any problems found?YesRepair as necessary.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace the Engine Control Module (ECM) in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)