P0046 - TURBOCHARGER BOOST CONTROL CIRCUIT/EXCESSIVE CURRENT

For a complete wiring diagram Refer to Section 8W

Theory of Operation


The 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.



Possible Causes
INTERMITTENT DTC
TURBOCHARGER MECHANICAL PROBLEM
(Z906) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
(F344) FUSED ASD RELAY OUTPUT CIRCUIT OPEN OR HIGH RESISTANCE
BOOST PRESSURE SERVO MOTOR

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)


1. (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.

NOTE: 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?

Yes


No

2. (Z906) GROUND CIRCUIT OPEN OR HIGH RESISTANCE

Turn the ignition off.
Using a 12 volt test light connected to 12 volts, check the (Z906) Ground circuit in the Boost Pressure Servo Motor harness connector.

NOTE: 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?

Yes


No

3. TURBOCHARGER MECHANICAL PROBLEM

Ensure the ignition is off.
Inspect the Turbocharger and Boost Pressure Servo Motor linkage for damage, debri and other problems that could effect Turbocharger vane movement.

Were any problems found?

Yes


No