Diagnostic Aids

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

If any service has been performed on the turbocharger or on the turbocharger components, a turbocharger relearn must be performed. Failure to perform the turbocharger learn procedure may cause this DTC to set. Refer to Turbocharger Learn Procedure .
For an intermittent condition, refer to Intermittent Conditions .

DTC P0046

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check - Engine Controls?	-	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	Turn ON the ignition, with the engine OFF. Monitor the Diagnostic Trouble Code (DTC) Information with a scan tool. Is DTC P0652, P0653, P2563, P2564, or P2565 also set?	-	Go to Diagnostic Trouble Code (DTC) List	Go to Step 3
3	Perform the Turbocharger Learn Procedure. Refer to Turbocharger Learn Procedure . Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Clear the DTCs with the scan tool. Is the procedure complete?	-	Go to Step 4	-
4	Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 5	Go to Diagnostic Aids
5	Turn OFF the ignition for 30 seconds. Disconnect the turbocharger vane position sensor. Test for an intermittent and for a poor connection at the vane position sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 18	Go to Step 6
6	Disconnect the engine control module (ECM). Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 18	Go to Step 7
7	Measure the resistance of the 5-volt reference circuit between the vane position sensor and the ECM, with a DMM. Is the resistance more than the specified value?	5 ohm	Go to Step 16	Go to Step 8
8	Measure the resistance of the signal circuit between the vane position sensor and the ECM, with a DMM. Is the resistance more than the specified value?	5 ohm	Go to Step 16	Go to Step 9
9	Connect the vane position sensor. Disconnect the turbocharger vane position control solenoid valve. Test the turbocharger vane position control solenoid valve high control circuit for a short to voltage. Did you find and correct the condition?	-	Go to Step 18	Go to Step 10
10	Test for an intermittent and for a poor connection at the vane control solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 18	Go to Step 11
11	Measure the resistance of the control circuit between the solenoid valve and the ECM, with a DMM. Is the resistance more than the specified value?	3 ohm	Go to Step 16	Go to Step 12
12	Measure the resistance of the low reference circuit between the solenoid valve and the ECM, with a DMM. Is the resistance more than the specified value?	3 ohm	Go to Step 16	Go to Step 13
13	Remove the turbocharger vane position control solenoid valve. Refer toTurbocharger Vane Position Control Solenoid Valve Replacement . IMPORTANT: The solenoid valve may be in 3 different positions: Open-Light is visible through the slot. Closed-The surface of the valve in the slot is smooth. At Rest-The surface of the valve in the slot is serrated. Observe both sets of slots on the side of the valve. A serrated surface, which is part of the sliding piece visible through the slots, should be fully visible in both slots. Is the serrated surface visible through the solenoid valve slots?	-	Go to Step 14	Go to Step 17
14	Connect the ECM. Connect the turbocharger vane control solenoid valve connector. Turn ON the ignition, with the engine OFF. Depress and hold the button at the tip of the control solenoid valve. Command the control solenoid valve ON with the scan tool. Observe the slot closest to the button when commanding the solenoid valve ON. Does the spool valve move and open the slot on the vane control solenoid valve when commanded ON?	-	Go to Step 15	Go to Step 17
15	Inspect the turbocharger for debris or damage. Refer to Turbocharger Cleaning and Inspection in Engine Mechanical. If required, replace the turbocharger. Refer to Turbocharger Replacement in Engine Mechanical. Is the procedure complete?	-	Go to Step 18	-
16	Repair the high resistance in the circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	-	Go to Step 18	-
17	Replace the turbocharger vane control solenoid valve. Refer to Turbocharger Vane Position Control Solenoid Valve Replacement . Did you complete the replacement?	-	Go to Step 18	-
18	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Perform the turbocharger learn procedure. Refer to Turbocharger Learn Procedure . Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 2	Go to Step 19
19	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List	System OK