Turbocharger Boost Control Circuit Low

2526 - TURBOCHARGER BOOST CONTROL CIRCUIT LOW





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on and the Boost Pressure Servo Motor command off.

- Set Condition:
The ECM detects that the Boost Pressure Servo Motor Control circuit is shorted to ground for 5.3 seconds.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. DTC IS ACTIVE
Ignition 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.
Monitor the scan tool for at least two minutes.
With the scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go To 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Component Tests and General Diagnostics

2. 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 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

- Go to 3

No

- Repair the Fused ASD Relay Output circuit for an open circuit or high resistance.
- Perform the ECM Verification Test Ver. 1. Powertrain Verification Test

3. 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 Boost Pressure Servo Motor Control circuit in the Boost Pressure Servo Motor harness connector.
Is the resistance above 1000 ohms?

Yes

- Go to 4

No

- Repair the Boost Pressure Servo Motor Control circuit for a short to ground.
- Perform the ECM Verification Test Ver. 1. Powertrain Verification Test

4. BOOST PRESSURE SERVO MOTOR CONTROL CIRCUIT OPEN OR HIGH RESISTANCE
Measure the resistance of the 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?

Yes

- Go to 5

No

- Repair the Boost Pressure Servo Motor Control circuit for an open circuit or high resistance.
- Perform the ECM Verification Test Ver. 1. Powertrain Verification Test

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 Boost Pressure Servo Motor Control 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.

NOTE: 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 Boost Pressure Servo Motor Control circuit in the Boost Pressure Servo Motor harness connector.

NOTE: The test light should not be illuminated.

NOTE: 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%?

Yes

- Replace the Boost Pressure Servo Motor.
- Perform the ECM Verification Test Ver. 1. Powertrain Verification Test

No

- Go to 6

6. 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.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. Powertrain Verification Test

No

- Replace the Engine Control Module (ECM).
- Perform the ECM Verification Test Ver. 1. Powertrain Verification Test